hadoop/CHANGES.txt

Hadoop Change Log

Trunk (unreleased changes)

  INCOMPATIBLE CHANGES

    HADOOP-3595. Remove deprecated methods for mapred.combine.once 
    functionality, which was necessary to providing backwards
    compatible combiner semantics for 0.18. (cdouglas via omalley)

    HADOOP-3667. Remove the following deprecated methods from JobConf:
      addInputPath(Path)
      getInputPaths()
      getMapOutputCompressionType()
      getOutputPath()
      getSystemDir()
      setInputPath(Path)
      setMapOutputCompressionType(CompressionType style)
      setOutputPath(Path)
    (Amareshwari Sriramadasu via omalley)

    HADOOP-3652. Remove deprecated class OutputFormatBase.
    (Amareshwari Sriramadasu via cdouglas)

    HADOOP-2885. Break the hadoop.dfs package into separate packages under
    hadoop.hdfs that reflect whether they are client, server, protocol, 
    etc. DistributedFileSystem and DFSClient have moved and are now 
    considered package private. (Sanjay Radia via omalley)

    HADOOP-2325.  Require Java 6. (cutting)

    HADOOP-372.  Add support for multiple input paths with a different
    InputFormat and Mapper for each path.  (Chris Smith via tomwhite)

    HADOOP-1700.  Support appending to file in HDFS. (dhruba)

    HADOOP-3792. Make FsShell -test consistent with unix semantics, returning
    zero for true and non-zero for false. (Ben Slusky via cdouglas)

    HADOOP-3664. Remove the deprecated method InputFormat.validateInput,
    which is no longer needed. (tomwhite via omalley)

  NEW FEATURES

    HADOOP-3341. Allow streaming jobs to specify the field separator for map
    and reduce input and output. The new configuration values are:
      stream.map.input.field.separator
      stream.map.output.field.separator
      stream.reduce.input.field.separator
      stream.reduce.output.field.separator
    All of them default to "\t". (Zheng Shao via omalley)

    HADOOP-3479. Defines the configuration file for the resource manager in 
    Hadoop. You can configure various parameters related to scheduling, such 
    as queues and queue properties here. The properties for a queue follow a
    naming convention,such as, hadoop.rm.queue.queue-name.property-name.
    (Hemanth Yamijala via ddas)

    HADOOP-3149. Adds a way in which map/reducetasks can create multiple 
    outputs. (Alejandro Abdelnur via ddas)

    HADOOP-3714.  Add a new contrib, bash-tab-completion, which enables 
    bash tab completion for the bin/hadoop script. See the README file
    in the contrib directory for the installation. (Chris Smith via enis)

    HADOOP-3730. Adds a new JobConf constructor that disables loading
    default configurations. (Alejandro Abdelnur via ddas)

    HADOOP-3772. Add a new Hadoop Instrumentation api for the JobTracker and
    the TaskTracker, refactor Hadoop Metrics as an implementation of the api.
    (Ari Rabkin via acmurthy) 

    HADOOP-2302. Provides a comparator for numerical sorting of key fields.
    (ddas)

    HADOOP-153. Provides a way to skip bad records. (Sharad Agarwal via ddas)

    HADOOP-657. Free disk space should be modelled and used by the scheduler
    to make scheduling decisions. (Ari Rabkin via omalley)

    HADOOP-3719. Initial checkin of Chukwa, which is a data collection and 
    analysis framework. (Jerome Boulon, Andy Konwinski, Ari Rabkin, 
    and Eric Yang)

    HADOOP-3873. Add -filelimit and -sizelimit options to distcp to cap the
    number of files/bytes copied in a particular run to support incremental
    updates and mirroring. (TszWo (Nicholas), SZE via cdouglas)

    HADOOP-3585. FailMon package for hardware failure monitoring and 
    analysis of anomalies. (Ioannis Koltsidas via dhruba)

  IMPROVEMENTS

    HADOOP-3732. Delay intialization of datanode block verification till
    the verification thread is started. (rangadi)

    HADOOP-1627. Various small improvements to 'dfsadmin -report' output.
    (rangadi)

    HADOOP-3577. Tools to inject blocks into name node and simulated
    data nodes for testing. (Sanjay Radia via hairong)

    HADOOP-2664. Add a lzop compatible codec, so that files compressed by lzop
    may be processed by map/reduce. (cdouglas via omalley)

    HADOOP-3655. Add additional ant properties to control junit. (Steve 
    Loughran via omalley)

    HADOOP-3543. Update the copyright year to 2008. (cdouglas via omalley)

    HADOOP-3587. Add a unit test for the contrib/data_join framework.
    (cdouglas)

    HADOOP-3402. Add terasort example program (omalley)

    HADOOP-3660. Add replication factor for injecting blocks in simulated
    datanodes. (Sanjay Radia via cdouglas)

    HADOOP-3684. Add a cloning function to the contrib/data_join framework
    permitting users to define a more efficient method for cloning values from
    the reduce than serialization/deserialization. (Runping Qi via cdouglas)

    HADOOP-3478. Improves the handling of map output fetching. Now the
    randomization is by the hosts (and not the map outputs themselves). 
    (Jothi Padmanabhan via ddas)

    HADOOP-3617. Removed redundant checks of accounting space in MapTask and
    makes the spill thread persistent so as to avoid creating a new one for
    each spill. (Chris Douglas via acmurthy)  

    HADOOP-3412. Factor the scheduler out of the JobTracker and make
    it pluggable. (Tom White and Brice Arnould via omalley)

    HADOOP-3756. Minor. Remove unused dfs.client.buffer.dir from 
    hadoop-default.xml. (rangadi)

    HADOOP-3327. Treats connection and read timeouts differently in the 
    shuffle and the backoff logic is dependent on the type of timeout.
    (Jothi Padmanabhan via ddas)

    HADOOP-3747. Adds counter suport for MultipleOutputs. 
    (Alejandro Abdelnur via ddas)

    HADOOP-3169. LeaseChecker daemon should not be started in DFSClient
    constructor. (TszWo (Nicholas), SZE via hairong)

    HADOOP-3824. Move base functionality of StatusHttpServer to a core
    package. (TszWo (Nicholas), SZE via cdouglas)

    HADOOP-3646. Add a bzip2 compatible codec, so bzip compressed data
    may be processed by map/reduce. (Abdul Qadeer via cdouglas)

    HADOOP-3861. MapFile.Reader and Writer should implement Closeable.
    (tomwhite via omalley)

    HADOOP-3791. Introduce generics into ReflectionUtils. (Chris Smith via
    cdouglas)

    HADOOP-3694. Improve unit test performance by changing
    MiniDFSCluster to listen only on 127.0.0.1.  (cutting)

    HADOOP-3620. Namenode should synchronously resolve a datanode's network
    location when the datanode registers. (hairong)

    HADOOP-3860. NNThroughputBenchmark is extended with rename and delete 
    benchmarks. (shv)
    
    HADOOP-3892. Include unix group name in JobConf. (Matei Zaharia via johan)

    HADOOP-3875. Change the time period between heartbeats to be relative to
    the end of the heartbeat rpc, rather than the start. This causes better
    behavior if the JobTracker is overloaded. (acmurthy via omalley)

    HADOOP-3853. Move multiple input format (HADOOP-372) extension to 
    library package. (tomwhite via johan)

    HADOOP-9. Use roulette scheduling for temporary space when the size
    is not known. (Ari Rabkin via omalley)

    HADOOP-3202. Use recursive delete rather than FileUtil.fullyDelete.
    (Amareshwari Sriramadasu via omalley)

    HADOOP-3368. Remove common-logging.properties from conf. (Steve Loughran 
    via omalley)

    HADOOP-3851. Fix spelling mistake in FSNamesystemMetrics. (Steve Loughran 
    via omalley)

    HADOOP-3780. Remove asynchronous resolution of network topology in the 
    JobTracker (Amar Kamat via omalley)

    HADOOP-3852. Add ShellCommandExecutor.toString method to make nicer
    error messages. (Steve Loughran via omalley)

    HADOOP-3844. Include message of local exception in RPC client failures.
    (Steve Loughran via omalley)

    HADOOP-3935. Split out inner classes from DataNode.java. (johan)

    HADOOP-3905. Create generic interfaces for edit log streams. (shv)

  OPTIMIZATIONS

    HADOOP-3556. Removed lock contention in MD5Hash by changing the 
    singleton MessageDigester by an instance per Thread using 
    ThreadLocal. (Iv?n de Prado via omalley)

    HADOOP-3328. When client is writing data to DFS, only the last 
    datanode in the pipeline needs to verify the checksum. Saves around
    30% CPU on intermediate datanodes. (rangadi)

    HADOOP-3863. Use a thread-local string encoder rather than a static one
    that is protected by a lock. (acmurthy via omalley)

    HADOOP-3864. Prevent the JobTracker from locking up when a job is being
    initialized. (acmurthy via omalley)

    HADOOP-3816. Faster directory listing in KFS. (Sriram Rao via omalley)

  BUG FIXES

    HADOOP-3563.  Refactor the distributed upgrade code so that it is 
    easier to identify datanode and namenode related code. (dhruba)

    HADOOP-3640. Fix the read method in the NativeS3InputStream. (tomwhite via
    omalley)

    HADOOP-3711. Fixes the Streaming input parsing to properly find the 
    separator. (Amareshwari Sriramadasu via ddas)

    HADOOP-3725. Prevent TestMiniMRMapDebugScript from swallowing exceptions.
    (Steve Loughran via cdouglas)

    HADOOP-3726. Throw exceptions from TestCLI setup and teardown instead of
    swallowing them. (Steve Loughran via cdouglas)

    HADOOP-3721. Refactor CompositeRecordReader and related mapred.join classes
    to make them clearer. (cdouglas)

    HADOOP-3720. Re-read the config file when dfsadmin -refreshNodes is invoked
    so dfs.hosts and dfs.hosts.exclude are observed. (lohit vijayarenu via
    cdouglas)

    HADOOP-3485. Allow writing to files over fuse.
    (Pete Wyckoff via dhruba)

    HADOOP-3723. The flags to the libhdfs.create call can be treated as
    a bitmask. (Pete Wyckoff via dhruba)

    HADOOP-3643. Filter out completed tasks when asking for running tasks in
    the JobTracker web/ui. (Amar Kamat via omalley)

    HADOOP-3777. Ensure that Lzo compressors/decompressors correctly handle the
    case where native libraries aren't available. (Chris Douglas via acmurthy) 

    HADOOP-3728. Fix SleepJob so that it doesn't depend on temporary files,
    this ensures we can now run more than one instance of SleepJob
    simultaneously. (Chris Douglas via acmurthy) 

    HADOOP-3795. Fix saving image files on Namenode with different checkpoint
    stamps. (Lohit Vijayarenu via mahadev)
   
    HADOOP-3624. Improving createeditslog to create tree directory structure.
    (Lohit Vijayarenu via mahadev)

    HADOOP-3778. DFSInputStream.seek() did not retry in case of some errors.
    (LN via rangadi)

    HADOOP-3661. The handling of moving files deleted through fuse-dfs to
    Trash made similar to the behaviour from dfs shell.
    (Pete Wyckoff via dhruba)

    HADOOP-3819. Unset LANG and LC_CTYPE in saveVersion.sh to make it
    compatible with non-English locales. (Rong-En Fan via cdouglas)

    HADOOP-3848. Cache calls to getSystemDir in the TaskTracker instead of
    calling it for each task start. (acmurthy via omalley)

    HADOOP-3131. Fix reduce progress reporting for compressed intermediate
    data. (Matei Zaharia via acmurthy) 

    HADOOP-3796. fuse-dfs configuration is implemented as file system
    mount options. (Pete Wyckoff via dhruba)

    HADOOP-3836. Fix TestMultipleOutputs to correctly clean up. (Alejandro 
    Abdelnur via acmurthy)

    HADOOP-3805. Improve fuse-dfs write performance.
    (Pete Wyckoff via zshao)

    HADOOP-3846. Fix unit test CreateEditsLog to generate paths correctly. 
    (Lohit Vjayarenu via cdouglas)
    
    HADOOP-3904. Fix unit tests using the old dfs package name.
    (TszWo (Nicholas), SZE via johan)

    HADOOP-3319. Fix some HOD error messages to go stderr instead of
    stdout. (Vinod Kumar Vavilapalli via omalley)

    HADOOP-3907. Move INodeDirectoryWithQuota to its own .java file.
    (Tsz Wo (Nicholas), SZE via hairong)

    HADOOP-3919. Fix attribute name in hadoop-default for 
    mapred.jobtracker.instrumentation. (Ari Rabkin via omalley)

    HADOOP-3903. Change the package name for the servlets to be hdfs instead of
    dfs. (Tsz Wo (Nicholas) Sze via omalley)

    HADOOP-3773. Change Pipes to set the default map output key and value 
    types correctly. (Koji Noguchi via omalley)

    HADOOP-3940. Fix in-memory merge condition to wait when there are no map
    outputs or when the final map outputs are being fetched without contention.
    (cdouglas)

    HADOOP-3952. Fix compilation error in TestDataJoin referencing dfs package.
    (omalley)

    HADOOP-3951. Fix package name for FSNamesystem logs and modify other
    hard-coded Logs to use the class name. (cdouglas)

    HADOOP-3889. Improve error reporting from HftpFileSystem, handling in
    DistCp. (Tsz Wo (Nicholas), SZE via cdouglas)

    HADOOP-3946. Fix TestMapRed after hadoop-3664. (tomwhite via omalley)

    HADOOP-3949. Remove duplicate jars from Chukwa. (Jerome Boulon via omalley)

    HADOOP-3933. DataNode sometimes sends up to io.byte.per.checksum bytes 
    more than required to client. (Ning Li via rangadi)

    HADOOP-3962. Shell command "fs -count" should support paths with different
    file systems. (Tsz Wo (Nicholas), SZE via mahadev)

    HADOOP-3957. Fix javac warnings in DistCp and TestCopyFiles. (Tsz Wo
    (Nicholas), SZE via cdouglas)

Release 0.18.0 - 2008-08-19

  INCOMPATIBLE CHANGES

    HADOOP-2703.  The default options to fsck skips checking files
    that are being written to. The output of fsck is incompatible
    with previous release. (lohit vijayarenu via dhruba) 

    HADOOP-2865. FsShell.ls() printout format changed to print file names
    in the end of the line. (Edward J. Yoon via shv)

    HADOOP-3283. The Datanode has a RPC server. It currently supports
    two RPCs: the first RPC retrives the metadata about a block and the
    second RPC sets the generation stamp of an existing block.
    (Tsz Wo (Nicholas), SZE via dhruba)

    HADOOP-2797. Code related to upgrading to 0.14 (Block CRCs) is 
    removed. As result, upgrade to 0.18 or later from 0.13 or earlier
    is not supported. If upgrading from 0.13 or earlier is required,
    please upgrade to an intermediate version (0.14-0.17) and then
    to this version. (rangadi)

    HADOOP-544. This issue introduces new classes JobID, TaskID and 
    TaskAttemptID, which should be used instead of their string counterparts.
    Functions in JobClient, TaskReport, RunningJob, jobcontrol.Job and 
    TaskCompletionEvent that use string arguments are deprecated in favor 
    of the corresponding ones that use ID objects. Applications can use 
    xxxID.toString() and xxxID.forName() methods to convert/restore objects 
    to/from strings. (Enis Soztutar via ddas)

    HADOOP-2188. RPC client sends a ping rather than throw timeouts.
    RPC server does not throw away old RPCs. If clients and the server are on
    different versions, they are not able to function well. In addition,
    The property ipc.client.timeout is removed from the default hadoop
    configuration. It also removes metrics RpcOpsDiscardedOPsNum. (hairong)

    HADOOP-2181. This issue adds logging for input splits in Jobtracker log 
    and jobHistory log. Also adds web UI for viewing input splits in job UI 
    and history UI. (Amareshwari Sriramadasu via ddas)

    HADOOP-3226. Run combiners multiple times over map outputs as they
    are merged in both the map and the reduce tasks. (cdouglas via omalley)

    HADOOP-3329.  DatanodeDescriptor objects should not be stored in the
    fsimage. (dhruba)

    HADOOP-2656.  The Block object has a generation stamp inside it.
    Existing blocks get a generation stamp of 0. This is needed to support
    appends. (dhruba)

    HADOOP-3390. Removed deprecated ClientProtocol.abandonFileInProgress().
    (Tsz Wo (Nicholas), SZE via rangadi)

    HADOOP-3405. Made some map/reduce internal classes non-public:
    MapTaskStatus, ReduceTaskStatus, JobSubmissionProtocol, 
    CompletedJobStatusStore. (enis via omaley)

    HADOOP-3265. Removed depcrecated API getFileCacheHints().
    (Lohit Vijayarenu via rangadi)

    HADOOP-3310. The namenode instructs the primary datanode to do lease
    recovery. The block gets a new  generation stamp.
    (Tsz Wo (Nicholas), SZE via dhruba)

    HADOOP-2909. Improve IPC idle connection management. Property
    ipc.client.maxidletime is removed from the default configuration,
    instead it is defined as twice of the ipc.client.connection.maxidletime.
    A connection with outstanding requests won't be treated as idle.
    (hairong)

    HADOOP-3459. Change in the output format of dfs -ls to more closely match
    /bin/ls. New format is: perm repl owner group size date name
    (Mukund Madhugiri via omally)

    HADOOP-3113. An fsync invoked on a HDFS file really really
    persists data! The datanode moves blocks in the tmp directory to 
    the real block directory on a datanode-restart. (dhruba)

    HADOOP-3452. Change fsck to return non-zero status for a corrupt
    FileSystem. (lohit vijayarenu via cdouglas)

    HADOOP-3193. Include the address of the client that found the corrupted
    block in the log. Also include a CorruptedBlocks metric to track the size
    of the corrupted block map. (cdouglas)

    HADOOP-3512. Separate out the tools into a tools jar. (omalley)

    HADOOP-3598. Ensure that temporary task-output directories are not created
    if they are not necessary e.g. for Maps with no side-effect files.
    (acmurthy)

    HADOOP-3665. Modify WritableComparator so that it only creates instances
    of the keytype if the type does not define a WritableComparator. Calling
    the superclass compare will throw a NullPointerException. Also define
    a RawComparator for NullWritable and permit it to be written as a key
    to SequenceFiles. (cdouglas)

    HADOOP-3673. Avoid deadlock caused by DataNode RPC receoverBlock().
    (Tsz Wo (Nicholas), SZE via rangadi)

  NEW FEATURES

    HADOOP-3074. Provides a UrlStreamHandler for DFS and other FS,
    relying on FileSystem (taton)

    HADOOP-2585. Name-node imports namespace data from a recent checkpoint
    accessible via a NFS mount. (shv)

    HADOOP-3061. Writable types for doubles and bytes. (Andrzej
    Bialecki via omalley)

    HADOOP-2857. Allow libhdfs to set jvm options. (Craig Macdonald
    via omalley)

    HADOOP-3317. Add default port for HDFS namenode.  The port in
    "hdfs:" URIs now defaults to 8020, so that one may simply use URIs
    of the form "hdfs://example.com/dir/file". (cutting)

    HADOOP-2019. Adds support for .tar, .tgz and .tar.gz files in 
    DistributedCache (Amareshwari Sriramadasu via ddas)

    HADOOP-3058. Add FSNamesystem status metrics. 
    (Lohit Vjayarenu via rangadi)

    HADOOP-1915. Allow users to specify counters via strings instead
    of enumerations. (tomwhite via omalley)

    HADOOP-2065. Delay invalidating corrupt replicas of block until its 
    is removed from under replicated state. If all replicas are found to 
    be corrupt, retain all copies and mark the block as corrupt.
    (Lohit Vjayarenu via rangadi)

    HADOOP-3221. Adds org.apache.hadoop.mapred.lib.NLineInputFormat, which 
    splits files into splits each of N lines. N can be specified by 
    configuration property "mapred.line.input.format.linespermap", which
    defaults to 1. (Amareshwari Sriramadasu via ddas) 

    HADOOP-3336. Direct a subset of annotated FSNamesystem calls for audit
    logging. (cdouglas)

    HADOOP-3400. A new API FileSystem.deleteOnExit() that facilitates
    handling of temporary files in HDFS. (dhruba)

    HADOOP-4.  Add fuse-dfs to contrib, permitting one to mount an
    HDFS filesystem on systems that support FUSE, e.g., Linux.
    (Pete Wyckoff via cutting)

    HADOOP-3246. Add FTPFileSystem.  (Ankur Goel via cutting)

    HADOOP-3250. Extend FileSystem API to allow appending to files.
    (Tsz Wo (Nicholas), SZE via cdouglas)

    HADOOP-3177. Implement Syncable interface for FileSystem.
    (Tsz Wo (Nicholas), SZE via dhruba)

    HADOOP-1328. Implement user counters in streaming. (tomwhite via
    omalley)

    HADOOP-3187. Quotas for namespace management. (Hairong Kuang via ddas)

    HADOOP-3307. Support for Archives in Hadoop. (Mahadev Konar via ddas)

    HADOOP-3460. Add SequenceFileAsBinaryOutputFormat to permit direct
    writes of serialized data. (Koji Noguchi via cdouglas)

    HADOOP-3230. Add ability to get counter values from command
    line. (tomwhite via omalley)

    HADOOP-930. Add support for native S3 files.  (tomwhite via cutting)

    HADOOP-3502. Quota API needs documentation in Forrest. (hairong)

    HADOOP-3413. Allow SequenceFile.Reader to use serialization
    framework. (tomwhite via omalley)

    HADOOP-3541. Import of the namespace from a checkpoint documented 
    in hadoop user guide. (shv)

  IMPROVEMENTS

    HADOOP-3677. Simplify generation stamp upgrade by making is a 
    local upgrade on datandodes. Deleted distributed upgrade.
    (rangadi)
   
    HADOOP-2928. Remove deprecated FileSystem.getContentLength().
    (Lohit Vjayarenu via rangadi)

    HADOOP-3130. Make the connect timeout smaller for getFile.
    (Amar Ramesh Kamat via ddas)

    HADOOP-3160. Remove deprecated exists() from ClientProtocol and 
    FSNamesystem (Lohit Vjayarenu via rangadi)

    HADOOP-2910. Throttle IPC Clients during bursts of requests or
    server slowdown. Clients retry connection for up to 15 minutes
    when socket connection times out. (hairong)

    HADOOP-3295. Allow TextOutputFormat to use configurable spearators.
    (Zheng Shao via cdouglas).

    HADOOP-3308. Improve QuickSort by excluding values eq the pivot from the
    partition. (cdouglas)

    HADOOP-2461. Trim property names in configuration.
    (Tsz Wo (Nicholas), SZE via shv)

    HADOOP-2799. Deprecate o.a.h.io.Closable in favor of java.io.Closable.
    (Tsz Wo (Nicholas), SZE via cdouglas)

    HADOOP-3345. Enhance the hudson-test-patch target to cleanup messages,
    fix minor defects, and add eclipse plugin and python unit tests. (nigel)

    HADOOP-3144. Improve robustness of LineRecordReader by defining a maximum
    line length (mapred.linerecordreader.maxlength), thereby avoiding reading
    too far into the following split. (Zheng Shao via cdouglas)

    HADOOP-3334. Move lease handling from FSNamesystem into a seperate class.
    (Tsz Wo (Nicholas), SZE via rangadi)

    HADOOP-3332. Reduces the amount of logging in Reducer's shuffle phase.
    (Devaraj Das)

    HADOOP-3355. Enhances Configuration class to accept hex numbers for getInt
    and getLong. (Amareshwari Sriramadasu via ddas)

    HADOOP-3350. Add an argument to distcp to permit the user to limit the
    number of maps. (cdouglas)

    HADOOP-3013. Add corrupt block reporting to fsck.
    (lohit vijayarenu via cdouglas)

    HADOOP-3377. Remove TaskRunner::replaceAll and replace with equivalent
    String::replace. (Brice Arnould via cdouglas)

    HADOOP-3398. Minor improvement to a utility function in that participates
    in backoff calculation. (cdouglas)

    HADOOP-3381. Clear referenced when directories are deleted so that 
    effect of memory leaks are not multiplied. (rangadi)

    HADOOP-2867. Adds the task's CWD to its LD_LIBRARY_PATH. 
    (Amareshwari Sriramadasu via ddas)

    HADOOP-3232. DU class runs the 'du' command in a seperate thread so
    that it does not block user. DataNode misses heartbeats in large
    nodes otherwise. (Johan Oskarsson via rangadi)

    HADOOP-3035. During block transfers between datanodes, the receiving
    datanode, now can report corrupt replicas received from src node to
    the namenode. (Lohit Vijayarenu via rangadi)

    HADOOP-3434. Retain the cause of the bind failure in Server::bind.
    (Steve Loughran via cdouglas)

    HADOOP-3429. Increases the size of the buffers used for the communication
    for Streaming jobs. (Amareshwari Sriramadasu via ddas)

    HADOOP-3486. Change default for initial block report to 0 seconds
    and document it. (Sanjay Radia via omalley)

    HADOOP-3448. Improve the text in the assertion making sure the
    layout versions are consistent in the data node. (Steve Loughran
    via omalley)

    HADOOP-2095. Improve the Map-Reduce shuffle/merge by cutting down
    buffer-copies; changed intermediate sort/merge to use the new IFile format
    rather than SequenceFiles and compression of map-outputs is now
    implemented by compressing the entire file rather than SequenceFile
    compression. Shuffle also has been changed to use a simple byte-buffer
    manager rather than the InMemoryFileSystem. 
    Configuration changes to hadoop-default.xml:
      deprecated mapred.map.output.compression.type 
    (acmurthy)

    HADOOP-236. JobTacker now refuses connection from a task tracker with a 
    different version number. (Sharad Agarwal via ddas)

    HADOOP-3427. Improves the shuffle scheduler. It now waits for notifications
    from shuffle threads when it has scheduled enough, before scheduling more.
    (ddas)

    HADOOP-2393. Moves the handling of dir deletions in the tasktracker to
    a separate thread. (Amareshwari Sriramadasu via ddas)

    HADOOP-3501. Deprecate InMemoryFileSystem. (cutting via omalley)

    HADOOP-3366. Stall the shuffle while in-memory merge is in progress.
    (acmurthy) 

    HADOOP-2916. Refactor src structure, but leave package structure alone.
    (Raghu Angadi via mukund) 

    HADOOP-3492. Add forrest documentation for user archives.
    (Mahadev Konar via hairong)

    HADOOP-3467. Improve documentation for FileSystem::deleteOnExit.
    (Tsz Wo (Nicholas), SZE via cdouglas)

    HADOOP-3379. Documents stream.non.zero.exit.status.is.failure for Streaming.
    (Amareshwari Sriramadasu via ddas)

    HADOOP-3096. Improves documentation about the Task Execution Environment in 
    the Map-Reduce tutorial. (Amareshwari Sriramadasu via ddas)

    HADOOP-2984. Add forrest documentation for DistCp. (cdouglas)

    HADOOP-3406. Add forrest documentation for Profiling.
    (Amareshwari Sriramadasu via ddas)

    HADOOP-2762. Add forrest documentation for controls of memory limits on 
    hadoop daemons and Map-Reduce tasks. (Amareshwari Sriramadasu via ddas)

    HADOOP-3535. Fix documentation and name of IOUtils.close to
    reflect that it should only be used in cleanup contexts. (omalley)

    HADOOP-3593. Updates the mapred tutorial. (ddas)

    HADOOP-3547. Documents the way in which native libraries can be distributed
    via the DistributedCache. (Amareshwari Sriramadasu via ddas)

    HADOOP-3606. Updates the Streaming doc. (Amareshwari Sriramadasu via ddas) 

    HADOOP-3532. Add jdiff reports to the build scripts. (omalley)

    HADOOP-3100. Develop tests to test the DFS command line interface. (mukund)

    HADOOP-3688. Fix up HDFS docs. (Robert Chansler via hairong)

  OPTIMIZATIONS

    HADOOP-3274. The default constructor of BytesWritable creates empty 
    byte array. (Tsz Wo (Nicholas), SZE via shv)

    HADOOP-3272. Remove redundant copy of Block object in BlocksMap.
    (Lohit Vjayarenu via shv)

    HADOOP-3164. Reduce DataNode CPU usage by using FileChannel.tranferTo().
    On Linux DataNode takes 5 times less CPU while serving data. Results may
    vary on other platforms. (rangadi)

    HADOOP-3248. Optimization of saveFSImage. (Dhruba via shv)

    HADOOP-3297. Fetch more task completion events from the job
    tracker and task tracker. (ddas via omalley)

    HADOOP-3364. Faster image and log edits loading. (shv)

    HADOOP-3369. Fast block processing during name-node startup. (shv)

    HADOOP-1702. Reduce buffer copies when data is written to DFS. 
    DataNodes take 30% less CPU while writing data. (rangadi)

    HADOOP-3095. Speed up split generation in the FileInputSplit,
    especially for non-HDFS file systems. Deprecates
    InputFormat.validateInput. (tomwhite via omalley)

    HADOOP-3552. Add forrest documentation for Hadoop commands.
    (Sharad Agarwal via cdouglas)

  BUG FIXES

    HADOOP-2905. 'fsck -move' triggers NPE in NameNode. 
    (Lohit Vjayarenu via rangadi)

    Increment ClientProtocol.versionID missed by HADOOP-2585. (shv)

    HADOOP-3254. Restructure internal namenode methods that process
    heartbeats to use well-defined BlockCommand object(s) instead of 
    using the base java Object. (Tsz Wo (Nicholas), SZE via dhruba)

    HADOOP-3176.  Change lease record when a open-for-write-file 
    gets renamed. (dhruba)

    HADOOP-3269.  Fix a case when namenode fails to restart
    while processing a lease record.  ((Tsz Wo (Nicholas), SZE via dhruba)

    HADOOP-3282. Port issues in TestCheckpoint resolved. (shv)

    HADOOP-3268. file:// URLs issue in TestUrlStreamHandler under Windows.
    (taton)

    HADOOP-3127. Deleting files in trash should really remove them.
    (Brice Arnould via omalley)

    HADOOP-3300. Fix locking of explicit locks in NetworkTopology.
    (tomwhite via omalley)

    HADOOP-3270. Constant DatanodeCommands are stored in static final
    immutable variables for better code clarity.  
    (Tsz Wo (Nicholas), SZE via dhruba)

    HADOOP-2793. Fix broken links for worst performing shuffle tasks in
    the job history page. (Amareshwari Sriramadasu via ddas)

    HADOOP-3313. Avoid unnecessary calls to System.currentTimeMillis
    in RPC::Invoker. (cdouglas)

    HADOOP-3318. Recognize "Darwin" as an alias for "Mac OS X" to
    support Soylatte. (Sam Pullara via omalley)

    HADOOP-3301. Fix misleading error message when S3 URI hostname
    contains an underscore. (tomwhite via omalley)

    HADOOP-3338. Fix Eclipse plugin to compile after HADOOP-544 was
    committed. Updated all references to use the new JobID representation.
    (taton via nigel)

    HADOOP-3337. Loading FSEditLog was broken by HADOOP-3283 since it 
    changed Writable serialization of DatanodeInfo. This patch handles it.
    (Tsz Wo (Nicholas), SZE via rangadi)

    HADOOP-3101. Prevent JobClient from throwing an exception when printing
    usage. (Edward J. Yoon via cdouglas)

    HADOOP-3119. Update javadoc for Text::getBytes to better describe its
    behavior. (Tim Nelson via cdouglas)

    HADOOP-2294. Fix documentation in libhdfs to refer to the correct free
    function. (Craig Macdonald via cdouglas)

    HADOOP-3335. Prevent the libhdfs build from deleting the wrong
    files on make clean. (cutting via omalley)

    HADOOP-2930. Make {start,stop}-balancer.sh work even if hadoop-daemon.sh
    is not in the PATH. (Spiros Papadimitriou via hairong)

    HADOOP-3085. Catch Exception in metrics util classes to ensure that
    misconfigured metrics don't prevent others from updating. (cdouglas)

    HADOOP-3299. CompositeInputFormat should configure the sub-input
    formats. (cdouglas via omalley)

    HADOOP-3309. Lower io.sort.mb and fs.inmemory.size.mb for MiniMRDFSSort
    unit test so it passes on Windows. (lohit vijayarenu via cdouglas)

    HADOOP-3348. TestUrlStreamHandler should set URLStreamFactory after
    DataNodes are initialized. (Lohit Vijayarenu via rangadi)

    HADOOP-3371. Ignore InstanceAlreadyExistsException from
    MBeanUtil::registerMBean. (lohit vijayarenu via cdouglas)

    HADOOP-3349. A file rename was incorrectly changing the name inside a
    lease record. (Tsz Wo (Nicholas), SZE via dhruba)

    HADOOP-3365. Removes an unnecessary copy of the key from SegmentDescriptor
    to MergeQueue. (Devaraj Das)

    HADOOP-3388. Fix for TestDatanodeBlockScanner to handle blocks with
    generation stamps in them.  (dhruba)

    HADOOP-3203. Fixes TaskTracker::localizeJob to pass correct file sizes
    for the jarfile and the jobfile. (Amareshwari Sriramadasu via ddas)

    HADOOP-3391. Fix a findbugs warning introduced by HADOOP-3248 (rangadi)

    HADOOP-3393. Fix datanode shutdown to call DataBlockScanner::shutdown and
    close its log, even if the scanner thread is not running. (lohit vijayarenu
    via cdouglas)

    HADOOP-3399. A debug message was logged at info level. (rangadi)

    HADOOP-3396. TestDatanodeBlockScanner occationally fails. 
    (Lohit Vijayarenu via rangadi)

    HADOOP-3339. Some of the failures on 3rd datanode in DFS write pipelie 
    are not detected properly. This could lead to hard failure of client's
    write operation. (rangadi)

    HADOOP-3409. Namenode should save the root inode into fsimage. (hairong)

    HADOOP-3296. Fix task cache to work for more than two levels in the cache
    hierarchy. This also adds a new counter to track cache hits at levels
    greater than two. (Amar Kamat via cdouglas)

    HADOOP-3375. Lease paths were sometimes not removed from 
    LeaseManager.sortedLeasesByPath. (Tsz Wo (Nicholas), SZE via dhruba)

    HADOOP-3424. Values returned by getPartition should be checked to
    make sure they are in the range 0 to #reduces - 1 (cdouglas via
    omalley)

    HADOOP-3408. Change FSNamesystem to send its metrics as integers to
    accommodate collectors that don't support long values. (lohit vijayarenu
    via cdouglas)

    HADOOP-3403. Fixes a problem in the JobTracker to do with handling of lost
    tasktrackers. (Arun Murthy via ddas)

    HADOOP-1318. Completed maps are not failed if the number of reducers are
    zero. (Amareshwari Sriramadasu via ddas).

    HADOOP-3351. Fixes the history viewer tool to not do huge StringBuffer
    allocations. (Amareshwari Sriramadasu via ddas)

    HADOOP-3419. Fixes TestFsck to wait for updates to happen before
    checking results to make the test more reliable. (Lohit Vijaya
    Renu via omalley)

    HADOOP-3259. Makes failure to read system properties due to a
    security manager non-fatal. (Edward Yoon via omalley)

    HADOOP-3451. Update libhdfs to use FileSystem::getFileBlockLocations
    instead of removed getFileCacheHints. (lohit vijayarenu via cdouglas)

    HADOOP-3401. Update FileBench to set the new
    "mapred.work.output.dir" property to work post-3041. (cdouglas via omalley)

    HADOOP-2669. DFSClient locks pendingCreates appropriately. (dhruba)
 
    HADOOP-3410. Fix KFS implemenation to return correct file
    modification time.  (Sriram Rao via cutting)

    HADOOP-3340. Fix DFS metrics for BlocksReplicated, HeartbeatsNum, and
    BlockReportsAverageTime. (lohit vijayarenu via cdouglas)

    HADOOP-3435. Remove the assuption in the scripts that bash is at
    /bin/bash and fix the test patch to require bash instead of sh.
    (Brice Arnould via omalley)

    HADOOP-3471. Fix spurious errors from TestIndexedSort and add additional
    logging to let failures be reproducible. (cdouglas)

    HADOOP-3443. Avoid copying map output across partitions when renaming a
    single spill. (omalley via cdouglas)

    HADOOP-3454. Fix Text::find to search only valid byte ranges. (Chad Whipkey
    via cdouglas)

    HADOOP-3417. Removes the static configuration variable,
    commandLineConfig from JobClient. Moves the cli parsing from
    JobShell to GenericOptionsParser.  Thus removes the class
    org.apache.hadoop.mapred.JobShell.  (Amareshwari Sriramadasu via
    ddas)

    HADOOP-2132. Only RUNNING/PREP jobs can be killed. (Jothi Padmanabhan 
    via ddas)

    HADOOP-3476. Code cleanup in fuse-dfs.
    (Peter Wyckoff via dhruba)

    HADOOP-2427. Ensure that the cwd of completed tasks is cleaned-up
    correctly on task-completion. (Amareshwari Sri Ramadasu via acmurthy) 

    HADOOP-2565. Remove DFSPath cache of FileStatus. 
    (Tsz Wo (Nicholas), SZE via hairong)

    HADOOP-3326. Cleanup the local-fs and in-memory merge in the ReduceTask by
    spawing only one thread each for the on-disk and in-memory merge.
    (Sharad Agarwal via acmurthy)

    HADOOP-3493. Fix TestStreamingFailure to use FileUtil.fullyDelete to
    ensure correct cleanup. (Lohit Vijayarenu via acmurthy) 

    HADOOP-3455. Fix NPE in ipc.Client in case of connection failure and
    improve its synchronization. (hairong)

    HADOOP-3240. Fix a testcase to not create files in the current directory.
    Instead the file is created in the test directory (Mahadev Konar via ddas)

    HADOOP-3496.  Fix failure in TestHarFileSystem.testArchives due to change
    in HADOOP-3095.  (tomwhite)

    HADOOP-3135. Get the system directory from the JobTracker instead of from
    the conf. (Subramaniam Krishnan via ddas)

    HADOOP-3503. Fix a race condition when client and namenode start
    simultaneous recovery of the same block.  (dhruba & Tsz Wo
    (Nicholas), SZE)

    HADOOP-3440. Fixes DistributedCache to not create symlinks for paths which
    don't have fragments even when createSymLink is true. 
    (Abhijit Bagri via ddas) 

    HADOOP-3463. Hadoop-daemons script should cd to $HADOOP_HOME. (omalley)

    HADOOP-3489. Fix NPE in SafeModeMonitor. (Lohit Vijayarenu via shv)

    HADOOP-3509. Fix NPE in FSNamesystem.close. (Tsz Wo (Nicholas), SZE via 
    shv)

    HADOOP-3491. Name-node shutdown causes InterruptedException in 
    ResolutionMonitor. (Lohit Vijayarenu via shv)

    HADOOP-3511. Fixes namenode image to not set the root's quota to an
    invalid value when the quota was not saved in the image. (hairong)

    HADOOP-3516. Ensure the JobClient in HadoopArchives is initialized
    with a configuration. (Subramaniam Krishnan via omalley)

    HADOOP-3513. Improve NNThroughputBenchmark log messages. (shv)

    HADOOP-3519.  Fix NPE in DFS FileSystem rename.  (hairong via tomwhite)
    
    HADOOP-3528. Metrics FilesCreated and files_deleted metrics
    do not match. (Lohit via Mahadev)

    HADOOP-3418. When a directory is deleted, any leases that point to files
    in the subdirectory are removed. ((Tsz Wo (Nicholas), SZE via dhruba)

    HADOOP-3542. Diables the creation of _logs directory for the archives
    directory. (Mahadev Konar via ddas)

    HADOOP-3544. Fixes a documentation issue for hadoop archives.
    (Mahadev Konar via ddas)

    HADOOP-3517. Fixes a problem in the reducer due to which the last InMemory
    merge may be missed. (Arun Murthy via ddas)

    HADOOP-3548. Fixes build.xml to copy all *.jar files to the dist.
    (Owen O'Malley via ddas)

    HADOOP-3363. Fix unformatted storage detection in FSImage. (shv)

    HADOOP-3560. Fixes a problem to do with split creation in archives.
    (Mahadev Konar via ddas)

    HADOOP-3545. Fixes a overflow problem in archives.
    (Mahadev Konar via ddas)

    HADOOP-3561. Prevent the trash from deleting its parent directories.
    (cdouglas)

    HADOOP-3575. Fix the clover ant target after package refactoring.
    (Nigel Daley via cdouglas)

    HADOOP-3539.  Fix the tool path in the bin/hadoop script under
    cygwin. (Tsz Wo (Nicholas), Sze via omalley)

    HADOOP-3520.  TestDFSUpgradeFromImage triggers a race condition in the
    Upgrade Manager. Fixed. (dhruba)

    HADOOP-3586. Provide deprecated, backwards compatibile semantics for the
    combiner to be run once and only once on each record. (cdouglas)

    HADOOP-3533. Add deprecated methods to provide API compatibility
    between 0.18 and 0.17. Remove the deprecated methods in trunk. (omalley)

    HADOOP-3580. Fixes a problem to do with specifying a har as an input to 
    a job. (Mahadev Konar via ddas)

    HADOOP-3333. Don't assign a task to a tasktracker that it failed to  
    execute earlier (used to happen in the case of lost tasktrackers where
    the tasktracker would reinitialize and bind to a different port). 
    (Jothi Padmanabhan and Arun Murthy via ddas)

    HADOOP-3534. Log IOExceptions that happen in closing the name
    system when the NameNode shuts down. (Tsz Wo (Nicholas) Sze via omalley)

    HADOOP-3546. TaskTracker re-initialization gets stuck in cleaning up.
    (Amareshwari Sriramadasu via ddas)

    HADOOP-3576. Fix NullPointerException when renaming a directory
    to its subdirectory. (Tse Wo (Nicholas), SZE via hairong)

    HADOOP-3320. Fix NullPointerException in NetworkTopology.getDistance().
    (hairong)

    HADOOP-3569. KFS input stream read() now correctly reads 1 byte
    instead of 4. (Sriram Rao via omalley)

    HADOOP-3599. Fix JobConf::setCombineOnceOnly to modify the instance rather
    than a parameter. (Owen O'Malley via cdouglas)

    HADOOP-3590. Null pointer exception in JobTracker when the task tracker is 
    not yet resolved. (Amar Ramesh Kamat via ddas)

    HADOOP-3603. Fix MapOutputCollector to spill when io.sort.spill.percent is
    1.0 and to detect spills when emitted records write no data. (cdouglas)

    HADOOP-3615. Set DatanodeProtocol.versionID to the correct value.
    (Tsz Wo (Nicholas), SZE via cdouglas)

    HADOOP-3559. Fix the libhdfs test script and config to work with the
    current semantics. (lohit vijayarenu via cdouglas)

    HADOOP-3480.  Need to update Eclipse template to reflect current trunk.
    (Brice Arnould via tomwhite)
  
    HADOOP-3588. Fixed usability issues with archives. (mahadev)

    HADOOP-3635. Uncaught exception in DataBlockScanner.
    (Tsz Wo (Nicholas), SZE via hairong)

    HADOOP-3639. Exception when closing DFSClient while multiple files are
    open. (Benjamin Gufler via hairong)

    HADOOP-3572. SetQuotas usage interface has some minor bugs. (hairong)

    HADOOP-3649. Fix bug in removing blocks from the corrupted block map.
    (Lohit Vijayarenu via shv)

    HADOOP-3604. Work around a JVM synchronization problem observed while
    retrieving the address of direct buffers from compression code by obtaining
    a lock during this call. (Arun C Murthy via cdouglas)

    HADOOP-3683. Fix dfs metrics to count file listings rather than files
    listed. (lohit vijayarenu via cdouglas)

    HADOOP-3597. Fix SortValidator to use filesystems other than the default as
    input. Validation job still runs on default fs.
    (Jothi Padmanabhan via cdouglas)

    HADOOP-3693. Fix archives, distcp and native library documentation to
    conform to style guidelines. (Amareshwari Sriramadasu via cdouglas)

    HADOOP-3653. Fix test-patch target to properly account for Eclipse
    classpath jars. (Brice Arnould via nigel)

    HADOOP-3692. Fix documentation for Cluster setup and Quick start guides. 
    (Amareshwari Sriramadasu via ddas)

    HADOOP-3691. Fix streaming and tutorial docs. (Jothi Padmanabhan via ddas)

    HADOOP-3630. Fix NullPointerException in CompositeRecordReader from empty
    sources (cdouglas)

    HADOOP-3706. Fix a ClassLoader issue in the mapred.join Parser that
    prevents it from loading user-specified InputFormats.
    (Jingkei Ly via cdouglas)

    HADOOP-3718. Fix KFSOutputStream::write(int) to output a byte instead of
    an int, per the OutputStream contract. (Sriram Rao via cdouglas)

    HADOOP-3647. Add debug logs to help track down a very occassional,
    hard-to-reproduce, bug in shuffle/merge on the reducer. (acmurthy) 

    HADOOP-3716. Prevent listStatus in KosmosFileSystem from returning
    null for valid, empty directories. (Sriram Rao via cdouglas)

    HADOOP-3752. Fix audit logging to record rename events. (cdouglas)

    HADOOP-3737. Fix CompressedWritable to call Deflater::end to release
    compressor memory. (Grant Glouser via cdouglas)

    HADOOP-3670. Fixes JobTracker to clear out split bytes when no longer 
    required. (Amareshwari Sriramadasu via ddas)

    HADOOP-3755. Update gridmix to work with HOD 0.4 (Runping Qi via cdouglas)
  
    HADOOP-3743. Fix -libjars, -files, -archives options to work even if 
    user code does not implement tools. (Amareshwari Sriramadasu via mahadev)

    HADOOP-3774. Fix typos in shell output. (Tsz Wo (Nicholas), SZE via
    cdouglas)

    HADOOP-3762. Fixed FileSystem cache to work with the default port. (cutting
    via omalley)

    HADOOP-3798. Fix tests compilation. (Mukund Madhugiri via omalley)

    HADOOP-3794. Return modification time instead of zero for KosmosFileSystem.
    (Sriram Rao via cdouglas)

    HADOOP-3806. Remove debug statement to stdout from QuickSort. (cdouglas)

    HADOOP-3776. Fix NPE at NameNode when datanode reports a block after it is
    deleted at NameNode. (rangadi)

    HADOOP-3537. Disallow adding a datanode to a network topology when its
    network location is not resolved. (hairong)

    HADOOP-3571. Fix bug in block removal used in lease recovery. (shv)

    HADOOP-3645. MetricsTimeVaryingRate returns wrong value for
    metric_avg_time. (Lohit Vijayarenu via hairong)

    HADOOP-3521. Reverted the missing cast to float for sending Counters' values
    to Hadoop metrics which was removed by HADOOP-544. (acmurthy)   

    HADOOP-3820. Fixes two problems in the gridmix-env - a syntax error, and a 
    wrong definition of USE_REAL_DATASET by default. (Arun Murthy via ddas)

    HADOOP-3724. Fixes two problems related to storing and recovering lease
    in the fsimage. (dhruba)
    
    HADOOP-3827.  Fixed compression of empty map-outputs. (acmurthy) 

    HADOOP-3865. Remove reference to FSNamesystem from metrics preventing
    garbage collection. (Lohit Vijayarenu via cdouglas)

    HADOOP-3884.  Fix so that Eclipse plugin builds against recent
    Eclipse releases.  (cutting)

    HADOOP-3837. Streaming jobs report progress status. (dhruba)

    HADOOP-3897. Fix a NPE in secondary namenode. (Lohit Vijayarenu via 
    cdouglas)

    HADOOP-3901. Fix bin/hadoop to correctly set classpath under cygwin.
    (Tsz Wo (Nicholas) Sze via omalley)

    HADOOP-3947. Fix a problem in tasktracker reinitialization. 
    (Amareshwari Sriramadasu via ddas)

Release 0.17.2 - 2008-08-11

  BUG FIXES

    HADOOP-3678. Avoid spurious exceptions logged at DataNode when clients
    read from DFS. (rangadi)

    HADOOP-3707. NameNode keeps a count of number of blocks scheduled
    to be written to a datanode and uses it to avoid allocating more
    blocks than a datanode can hold. (rangadi)

    HADOOP-3760. Fix a bug with HDFS file close() mistakenly introduced
    by HADOOP-3681. (Lohit Vijayarenu via rangadi)

    HADOOP-3681. DFSClient can get into an infinite loop while closing
    a file if there are some errors. (Lohit Vijayarenu via rangadi)

    HADOOP-3002. Hold off block removal while in safe mode. (shv)

    HADOOP-3685. Unbalanced replication target. (hairong)

    HADOOP-3758. Shutdown datanode on version mismatch instead of retrying
    continuously, preventing excessive logging at the namenode.
    (lohit vijayarenu via cdouglas)

    HADOOP-3633. Correct exception handling in DataXceiveServer, and throttle
    the number of xceiver threads in a data-node. (shv)

    HADOOP-3370. Ensure that the TaskTracker.runningJobs data-structure is
    correctly cleaned-up on task completion. (Zheng Shao via acmurthy) 

    HADOOP-3813. Fix task-output clean-up on HDFS to use the recursive 
    FileSystem.delete rather than the FileUtil.fullyDelete. (Amareshwari
    Sri Ramadasu via acmurthy)  

    HADOOP-3859. Allow the maximum number of xceivers in the data node to
    be configurable. (Johan Oskarsson via omalley)

    HADOOP-3931. Fix corner case in the map-side sort that causes some values 
    to be counted as too large and cause pre-mature spills to disk. Some values
    will also bypass the combiner incorrectly. (cdouglas via omalley)

Release 0.17.1 - 2008-06-23

  INCOMPATIBLE CHANGES

    HADOOP-3565. Fix the Java serialization, which is not enabled by
    default, to clear the state of the serializer between objects.
    (tomwhite via omalley)

  IMPROVEMENTS

    HADOOP-3522. Improve documentation on reduce pointing out that
    input keys and values will be reused. (omalley)

    HADOOP-3487. Balancer uses thread pools for managing its threads;
    therefore provides better resource management. (hairong)

  BUG FIXES

    HADOOP-2159 Namenode stuck in safemode. The counter blockSafe should
    not be decremented for invalid blocks. (hairong)

    HADOOP-3472 MapFile.Reader getClosest() function returns incorrect results
    when before is true (Todd Lipcon via Stack)

    HADOOP-3442. Limit recursion depth on the stack for QuickSort to prevent
    StackOverflowErrors. To avoid O(n*n) cases, when partitioning depth exceeds
    a multiple of log(n), change to HeapSort. (cdouglas)

    HADOOP-3477. Fix build to not package contrib/*/bin twice in
    distributions.  (Adam Heath via cutting)

    HADOOP-3475. Fix MapTask to correctly size the accounting allocation of
    io.sort.mb. (cdouglas)

    HADOOP-3550. Fix the serialization data structures in MapTask where the
    value lengths are incorrectly calculated. (cdouglas)

    HADOOP-3526. Fix contrib/data_join framework by cloning values retained
    in the reduce. (Spyros Blanas via cdouglas)

    HADOOP-1979. Speed up fsck by adding a buffered stream. (Lohit
    Vijaya Renu via omalley)

Release 0.17.0 - 2008-05-18

  INCOMPATIBLE CHANGES

    HADOOP-2786.  Move hbase out of hadoop core

    HADOOP-2345.  New HDFS transactions to support appending 
    to files.  Disk layout version changed from -11 to -12. (dhruba)

    HADOOP-2192. Error messages from "dfs mv" command improved.
    (Mahadev Konar via dhruba)

    HADOOP-1902. "dfs du" command without any arguments operates on the
    current working directory.  (Mahadev Konar via dhruba)

    HADOOP-2873.  Fixed bad disk format introduced by HADOOP-2345.
    Disk layout version changed from -12 to -13. See changelist 630992
    (dhruba)

    HADOOP-1985.  This addresses rack-awareness for Map tasks and for 
    HDFS in a uniform way. (ddas)

    HADOOP-1986.  Add support for a general serialization mechanism for
    Map Reduce. (tomwhite)

    HADOOP-771. FileSystem.delete() takes an explicit parameter that
    specifies whether a recursive delete is intended.
    (Mahadev Konar via dhruba)

    HADOOP-2470. Remove getContentLength(String), open(String, long, long)
    and isDir(String) from ClientProtocol. ClientProtocol version changed
    from 26 to 27. (Tsz Wo (Nicholas), SZE via cdouglas)

    HADOOP-2822. Remove deprecated code for classes InputFormatBase and 
    PhasedFileSystem. (Amareshwari Sriramadasu via enis)

    HADOOP-2116. Changes the layout of the task execution directory. 
    (Amareshwari Sriramadasu via ddas)

    HADOOP-2828. The following deprecated methods in Configuration.java
    have been removed
        getObject(String name)
        setObject(String name, Object value)
        get(String name, Object defaultValue)
        set(String name, Object value)
        Iterator entries()
    (Amareshwari Sriramadasu via ddas)

    HADOOP-2824. Removes one deprecated constructor from MiniMRCluster.
    (Amareshwari Sriramadasu via ddas)

    HADOOP-2823. Removes deprecated methods getColumn(), getLine() from
    org.apache.hadoop.record.compiler.generated.SimpleCharStream. 
    (Amareshwari Sriramadasu via ddas)

    HADOOP-3060. Removes one unused constructor argument from MiniMRCluster.
    (Amareshwari Sriramadasu via ddas)

    HADOOP-2854. Remove deprecated o.a.h.ipc.Server::getUserInfo().
    (lohit vijayarenu via cdouglas)

    HADOOP-2563. Remove deprecated FileSystem::listPaths.
    (lohit vijayarenu via cdouglas)

    HADOOP-2818.  Remove deprecated methods in Counters.
    (Amareshwari Sriramadasu via tomwhite)

    HADOOP-2831. Remove deprecated o.a.h.dfs.INode::getAbsoluteName()
    (lohit vijayarenu via cdouglas)

    HADOOP-2839. Remove deprecated FileSystem::globPaths.
    (lohit vijayarenu via cdouglas)

    HADOOP-2634. Deprecate ClientProtocol::exists.
    (lohit vijayarenu via cdouglas)

    HADOOP-2410.  Make EC2 cluster nodes more independent of each other.
    Multiple concurrent EC2 clusters are now supported, and nodes may be
    added to a cluster on the fly with new nodes starting in the same EC2
    availability zone as the cluster.  Ganglia monitoring and large
    instance sizes have also been added.  (Chris K Wensel via tomwhite)

    HADOOP-2826. Deprecated FileSplit.getFile(), LineRecordReader.readLine().
    (Amareshwari Sriramadasu via ddas)

    HADOOP-3239. getFileInfo() returns null for non-existing files instead
    of throwing FileNotFoundException. (Lohit Vijayarenu via shv)

    HADOOP-3266. Removed HOD changes from CHANGES.txt, as they are now inside 
    src/contrib/hod  (Hemanth Yamijala via ddas)

    HADOOP-3280. Separate the configuration of the virtual memory size
    (mapred.child.ulimit) from the jvm heap size, so that 64 bit
    streaming applications are supported even when running with 32 bit
    jvms. (acmurthy via omalley)

  NEW FEATURES

    HADOOP-1398.  Add HBase in-memory block cache.  (tomwhite)

    HADOOP-2178.  Job History on DFS. (Amareshwari Sri Ramadasu via ddas)

    HADOOP-2063. A new parameter to dfs -get command to fetch a file 
    even if it is corrupted.  (Tsz Wo (Nicholas), SZE via dhruba)

    HADOOP-2219. A new command "df -count" that counts the number of
    files and directories.  (Tsz Wo (Nicholas), SZE via dhruba)

    HADOOP-2906. Add an OutputFormat capable of using keys, values, and
    config params to map records to different output files.
    (Runping Qi via cdouglas)

    HADOOP-2346. Utilities to support timeout while writing to sockets.
    DFSClient and DataNode sockets have 10min write timeout. (rangadi)
    
    HADOOP-2951.  Add a contrib module that provides a utility to
    build or update Lucene indexes using Map/Reduce.  (Ning Li via cutting)

    HADOOP-1622.  Allow multiple jar files for map reduce.
    (Mahadev Konar via dhruba)

    HADOOP-2055. Allows users to set PathFilter on the FileInputFormat.
    (Alejandro Abdelnur via ddas)

    HADOOP-2551. More environment variables like HADOOP_NAMENODE_OPTS
    for better control of HADOOP_OPTS for each component. (rangadi)

    HADOOP-3001. Add job counters that measure the number of bytes
    read and written to HDFS, S3, KFS, and local file systems. (omalley)

    HADOOP-3048.  A new Interface and a default implementation to convert 
    and restore serializations of objects to/from strings. (enis)

  IMPROVEMENTS

    HADOOP-2655. Copy on write for data and metadata files in the 
    presence of snapshots. Needed for supporting appends to HDFS
    files. (dhruba) 

    HADOOP-1967.  When a Path specifies the same scheme as the default
    FileSystem but no authority, the default FileSystem's authority is
    used.  Also add warnings for old-format FileSystem names, accessor
    methods for fs.default.name, and check for null authority in HDFS.
    (cutting)

    HADOOP-2895. Let the profiling string be configurable.
    (Martin Traverso via cdouglas)

    HADOOP-910. Enables Reduces to do merges for the on-disk map output files 
    in parallel with their copying. (Amar Kamat via ddas)

    HADOOP-730. Use rename rather than copy for local renames. (cdouglas)

    HADOOP-2810. Updated the Hadoop Core logo. (nigel)

    HADOOP-2057.  Streaming should optionally treat a non-zero exit status
    of a child process as a failed task.  (Rick Cox via tomwhite)

    HADOOP-2765. Enables specifying ulimits for streaming/pipes tasks (ddas)

    HADOOP-2888. Make gridmix scripts more readily configurable and amenable
    to automated execution. (Mukund Madhugiri via cdouglas)

    HADOOP-2908.  A document that describes the DFS Shell command. 
    (Mahadev Konar via dhruba)

    HADOOP-2981.  Update README.txt to reflect the upcoming use of
    cryptography. (omalley)

    HADOOP-2804.  Add support to publish CHANGES.txt as HTML when running
    the Ant 'docs' target. (nigel)

    HADOOP-2559. Change DFS block placement to allocate the first replica
    locally, the second off-rack, and the third intra-rack from the
    second. (lohit vijayarenu via cdouglas)

    HADOOP-2939. Make the automated patch testing process an executable 
    Ant target, test-patch. (nigel)

    HADOOP-2239. Add HsftpFileSystem to permit transferring files over ssl.
    (cdouglas)

    HADOOP-2886.  Track individual RPC metrics.
    (girish vaitheeswaran via dhruba)

    HADOOP-2373. Improvement in safe-mode reporting. (shv)

    HADOOP-3091. Modify FsShell command -put to accept multiple sources.
    (Lohit Vijaya Renu via cdouglas)

    HADOOP-3092. Show counter values from job -status command.
    (Tom White via ddas)

    HADOOP-1228.  Ant task to generate Eclipse project files.  (tomwhite)

    HADOOP-3093. Adds Configuration.getStrings(name, default-value) and
    the corresponding setStrings. (Amareshwari Sriramadasu via ddas)

    HADOOP-3106. Adds documentation in forrest for debugging.
    (Amareshwari Sriramadasu via ddas)

    HADOOP-3099. Add an option to distcp to preserve user, group, and
    permission information. (Tsz Wo (Nicholas), SZE via cdouglas)

    HADOOP-2841. Unwrap AccessControlException and FileNotFoundException
    from RemoteException for DFSClient. (shv)

    HADOOP-3152.  Make index interval configuable when using
    MapFileOutputFormat for map-reduce job.  (Rong-En Fan via cutting)

    HADOOP-3143. Decrease number of slaves from 4 to 3 in TestMiniMRDFSSort,
    as Hudson generates false negatives under the current load.
    (Nigel Daley via cdouglas)

    HADOOP-3174. Illustrative example for MultipleFileInputFormat. (Enis
    Soztutar via acmurthy)  

    HADOOP-2993. Clarify the usage of JAVA_HOME in the Quick Start guide.
    (acmurthy via nigel)

    HADOOP-3124. Make DataNode socket write timeout configurable. (rangadi)

  OPTIMIZATIONS

    HADOOP-2790.  Fixed inefficient method hasSpeculativeTask by removing
    repetitive calls to get the current time and late checking to see if
    we want speculation on at all. (omalley)

    HADOOP-2758. Reduce buffer copies in DataNode when data is read from
    HDFS, without negatively affecting read throughput. (rangadi)

    HADOOP-2399. Input key and value to combiner and reducer is reused.
    (Owen O'Malley via ddas). 

    HADOOP-2423.  Code optimization in FSNamesystem.mkdirs.
    (Tsz Wo (Nicholas), SZE via dhruba)

    HADOOP-2606. ReplicationMonitor selects data-nodes to replicate directly
    from needed replication blocks instead of looking up for the blocks for 
    each live data-node. (shv)

    HADOOP-2148. Eliminate redundant data-node blockMap lookups. (shv)

    HADOOP-2027. Return the number of bytes in each block in a file
    via a single rpc to the namenode to speed up job planning. 
    (Lohit Vijaya Renu via omalley)

    HADOOP-2902.  Replace uses of "fs.default.name" with calls to the
    accessor methods added in HADOOP-1967.  (cutting)

    HADOOP-2119.  Optimize scheduling of jobs with large numbers of
    tasks by replacing static arrays with lists of runnable tasks. 
    (Amar Kamat via omalley)

    HADOOP-2919.  Reduce the number of memory copies done during the
    map output sorting. Also adds two config variables:
    io.sort.spill.percent - the percentages of io.sort.mb that should
                            cause a spill (default 80%)
    io.sort.record.percent - the percent of io.sort.mb that should
                             hold key/value indexes (default 5%)
    (cdouglas via omalley)

    HADOOP-3140. Doesn't add a task in the commit queue if the task hadn't
    generated any output. (Amar Kamat via ddas)

    HADOOP-3168. Reduce the amount of logging in streaming to an
    exponentially increasing number of records (up to 10,000
    records/log). (Zheng Shao via omalley)
 
  BUG FIXES

    HADOOP-2195. '-mkdir' behaviour is now closer to Linux shell in case of
    errors. (Mahadev Konar via rangadi)
    
    HADOOP-2190. bring behaviour '-ls' and '-du' closer to Linux shell 
    commands in case of errors. (Mahadev Konar via rangadi)
    
    HADOOP-2193. 'fs -rm' and 'fs -rmr' show error message when the target
    file does not exist. (Mahadev Konar via rangadi)
            
    HADOOP-2738 Text is not subclassable because set(Text) and compareTo(Object)
    access the other instance's private members directly. (jimk)

    HADOOP-2779.  Remove the references to HBase in the build.xml. (omalley)

    HADOOP-2194. dfs cat on a non-existent file throws FileNotFoundException.
    (Mahadev Konar via dhruba)

    HADOOP-2767. Fix for NetworkTopology erroneously skipping the last leaf 
    node on a rack. (Hairong Kuang and Mark Butler via dhruba)

    HADOOP-1593. FsShell works with paths in non-default FileSystem.
    (Mahadev Konar via dhruba)

    HADOOP-2191. du and dus command on non-existent directory gives 
    appropriate error message.  (Mahadev Konar via dhruba)

    HADOOP-2832. Remove tabs from code of DFSClient for better
    indentation. (dhruba)

    HADOOP-2844. distcp closes file handles for sequence files.
    (Tsz Wo (Nicholas), SZE via dhruba)

    HADOOP-2727. Fix links in Web UI of the hadoop daemons and some docs
    (Amareshwari Sri Ramadasu via ddas)

    HADOOP-2871. Fixes a problem to do with file: URI in the JobHistory init.
    (Amareshwari Sri Ramadasu via ddas)

    HADOOP-2800.  Deprecate SetFile.Writer constructor not the whole class.
    (Johan Oskarsson via tomwhite)

    HADOOP-2891.  DFSClient.close() closes all open files. (dhruba)

    HADOOP-2845.  Fix dfsadmin disk utilization report on Solaris.
    (Martin Traverso via tomwhite)

    HADOOP-2912. MiniDFSCluster restart should wait for namenode to exit
    safemode. This was causing TestFsck to fail.  (Mahadev Konar via dhruba)

    HADOOP-2820. The following classes in streaming are removed : 
    StreamLineRecordReader StreamOutputFormat StreamSequenceRecordReader.
    (Amareshwari Sri Ramadasu via ddas)

    HADOOP-2819. The following methods in JobConf are removed:
    getInputKeyClass() setInputKeyClass getInputValueClass()
    setInputValueClass(Class theClass) setSpeculativeExecution
    getSpeculativeExecution() (Amareshwari Sri Ramadasu via ddas)

    HADOOP-2817. Removes deprecated mapred.tasktracker.tasks.maximum and 
    ClusterStatus.getMaxTasks(). (Amareshwari Sri Ramadasu via ddas) 

    HADOOP-2821. Removes deprecated ShellUtil and ToolBase classes from
    the util package. (Amareshwari Sri Ramadasu via ddas) 

    HADOOP-2934. The namenode was encountreing a NPE while loading
    leases from the fsimage. Fixed. (dhruba)

    HADOOP-2938. Some fs commands did not glob paths.
    (Tsz Wo (Nicholas), SZE via rangadi)

    HADOOP-2943. Compression of intermediate map output causes failures
    in the merge. (cdouglas)

    HADOOP-2870.  DataNode and NameNode closes all connections while
    shutting down. (Hairong Kuang via dhruba)

    HADOOP-2973. Fix TestLocalDFS for Windows platform.
    (Tsz Wo (Nicholas), SZE via dhruba)

    HADOOP-2971. select multiple times if it returns early in 
    SocketIOWithTimeout. (rangadi)

    HADOOP-2955. Fix TestCrcCorruption test failures caused by HADOOP-2758
    (rangadi)

    HADOOP-2657. A flush call on the DFSOutputStream flushes the last
    partial CRC chunk too.  (dhruba)

    HADOOP-2974. IPC unit tests used "0.0.0.0" to connect to server, which
    is not always supported. (rangadi)

    HADOOP-2996. Fixes uses of StringBuffer in StreamUtils class.
    (Dave Brosius via ddas)

    HADOOP-2995. Fixes StreamBaseRecordReader's getProgress to return a 
    floating point number. (Dave Brosius via ddas)

    HADOOP-2972. Fix for a NPE in FSDataset.invalidate.
    (Mahadev Konar via dhruba)

    HADOOP-2994. Code cleanup for DFSClient: remove redundant 
    conversions from string to string.  (Dave Brosius via dhruba)

    HADOOP-3009. TestFileCreation sometimes fails because restarting
    minidfscluster sometimes creates datanodes with ports that are
    different from their original instance. (dhruba)

    HADOOP-2992. Distributed Upgrade framework works correctly with
    more than one upgrade object.  (Konstantin Shvachko via dhruba)

    HADOOP-2679. Fix a typo in libhdfs.  (Jason via dhruba)

    HADOOP-2976. When a lease expires, the Namenode ensures that 
    blocks of the file are adequately replicated. (dhruba)

    HADOOP-2901. Fixes the creation of info servers in the JobClient
    and JobTracker. Removes the creation from JobClient and removes
    additional info server from the JobTracker. Also adds the command
    line utility to view the history files (HADOOP-2896), and fixes
    bugs in JSPs to do with analysis - HADOOP-2742, HADOOP-2792.
    (Amareshwari Sri Ramadasu via ddas)

    HADOOP-2890. If different datanodes report the same block but
    with different sizes to the namenode, the namenode picks the
    replica(s) with the largest size as the only valid replica(s). (dhruba)

    HADOOP-2825. Deprecated MapOutputLocation.getFile() is removed.
    (Amareshwari Sri Ramadasu via ddas)

    HADOOP-2806. Fixes a streaming document.
    (Amareshwari Sriramadasu via ddas)

    HADOOP-3008. SocketIOWithTimeout throws InterruptedIOException if the
    thread is interrupted while it is waiting. (rangadi)
    
    HADOOP-3006. Fix wrong packet size reported by DataNode when a block
    is being replicated. (rangadi)

    HADOOP-3029. Datanode prints log message "firstbadlink" only if 
    it detects a bad connection to another datanode in the pipeline. (dhruba)

    HADOOP-3030. Release reserved space for file in InMemoryFileSystem if
    checksum reservation fails. (Devaraj Das via cdouglas)

    HADOOP-3036. Fix findbugs warnings in UpgradeUtilities. (Konstantin
    Shvachko via cdouglas)

    HADOOP-3025. ChecksumFileSystem supports the delete method with 
    the recursive flag. (Mahadev Konar via dhruba)

    HADOOP-3012. dfs -mv file to user home directory throws exception if 
    the user home directory does not exist. (Mahadev Konar via dhruba)
    
    HADOOP-3066. Should not require superuser privilege to query if hdfs is in
    safe mode (jimk)

    HADOOP-3040. If the input line starts with the separator char, the key
    is set as empty. (Amareshwari Sriramadasu via ddas) 

    HADOOP-3080. Removes flush calls from JobHistory.
    (Amareshwari Sriramadasu via ddas) 

    HADOOP-3086. Adds the testcase missed during commit of hadoop-3040.
    (Amareshwari Sriramadasu via ddas)

    HADOOP-3046. Fix the raw comparators for Text and BytesWritables
    to use the provided length rather than recompute it. (omalley)

    HADOOP-3094. Fix BytesWritable.toString to avoid extending the sign bit
    (Owen O'Malley via cdouglas)

    HADOOP-3067. DFSInputStream's position read does not close the sockets.
    (rangadi)

    HADOOP-3073. close() on SocketInputStream or SocketOutputStream should
    close the underlying channel. (rangadi)

    HADOOP-3087. Fixes a problem to do with refreshing of loadHistory.jsp.
    (Amareshwari Sriramadasu via ddas)

    HADOOP-3065. Better logging message if the rack location of a datanode
    cannot be determined.  (Devaraj Das via dhruba)

    HADOOP-3064. Commas in a file path should not be treated as delimiters.
    (Hairong Kuang via shv)

    HADOOP-2997. Adds test for non-writable serialier. Also fixes a problem 
    introduced by HADOOP-2399. (Tom White via ddas)

    HADOOP-3114. Fix TestDFSShell on Windows. (Lohit Vijaya Renu via cdouglas)

    HADOOP-3118.  Fix Namenode NPE while loading fsimage after a cluster 
    upgrade from older disk format. (dhruba)

    HADOOP-3161. Fix FIleUtil.HardLink.getLinkCount on Mac OS. (nigel
    via omalley)

    HADOOP-2927. Fix TestDU to acurately calculate the expected file size.
    (shv via nigel)

    HADOOP-3123. Fix the native library build scripts to work on Solaris.
    (tomwhite via omalley)

    HADOOP-3089.  Streaming should accept stderr from task before
    first key arrives.  (Rick Cox via tomwhite)

    HADOOP-3146. A DFSOutputStream.flush method is renamed as
    DFSOutputStream.fsync.  (dhruba)

    HADOOP-3165. -put/-copyFromLocal did not treat input file "-" as stdin.
    (Lohit Vijayarenu via rangadi)

    HADOOP-3041. Deprecate JobConf.setOutputPath and JobConf.getOutputPath.
    Deprecate OutputFormatBase. Add FileOutputFormat. Existing output formats
    extending OutputFormatBase, now extend FileOutputFormat. Add the following
    APIs in FileOutputFormat: setOutputPath, getOutputPath, getWorkOutputPath.
    (Amareshwari Sriramadasu via nigel)

    HADOOP-3083. The fsimage does not store leases. This would have to be
    reworked in the next release to support appends. (dhruba)

    HADOOP-3166. Fix an ArrayIndexOutOfBoundsException in the spill thread
    and make exception handling more promiscuous to catch this condition.
    (cdouglas)

    HADOOP-3050. DataNode sends one and only one block report after
    it registers with the namenode. (Hairong Kuang)

    HADOOP-3044. NNBench sets the right configuration for the mapper.
    (Hairong Kuang)

    HADOOP-3178. Fix GridMix scripts for small and medium jobs
    to handle input paths differently. (Mukund Madhugiri via nigel)

    HADOOP-1911. Fix an infinite loop in DFSClient when all replicas of a
    block are bad (cdouglas)

    HADOOP-3157. Fix path handling in DistributedCache and TestMiniMRLocalFS.
    (Doug Cutting via rangadi) 

    HADOOP-3018. Fix the eclipse plug-in contrib wrt removed deprecated
    methods (taton)

    HADOOP-3183. Fix TestJobShell to use 'ls' instead of java.io.File::exists
    since cygwin symlinks are unsupported.
    (Mahadev konar via cdouglas)

    HADOOP-3175. Fix FsShell.CommandFormat to handle "-" in arguments.
    (Edward J. Yoon via rangadi)

    HADOOP-3220. Safemode message corrected. (shv)

    HADOOP-3208. Fix WritableDeserializer to set the Configuration on
    deserialized Writables. (Enis Soztutar via cdouglas)

   HADOOP-3224. 'dfs -du /dir' does not return correct size.
   (Lohit Vjayarenu via rangadi)

   HADOOP-3223. Fix typo in help message for -chmod. (rangadi)

   HADOOP-1373. checkPath() should ignore case when it compares authoriy.
   (Edward J. Yoon via rangadi)

   HADOOP-3204. Fixes a problem to do with ReduceTask's LocalFSMerger not
   catching Throwable.  (Amar Ramesh Kamat via ddas)

    HADOOP-3229. Report progress when collecting records from the mapper and
    the combiner. (Doug Cutting via cdouglas)

    HADOOP-3225. Unwrapping methods of RemoteException should initialize
    detailedMassage field. (Mahadev Konar, shv, cdouglas)

    HADOOP-3247. Fix gridmix scripts to use the correct globbing syntax and
    change maxentToSameCluster to run the correct number of jobs.
    (Runping Qi via cdouglas)

    HADOOP-3242. Fix the RecordReader of SequenceFileAsBinaryInputFormat to
    correctly read from the start of the split and not the beginning of the
    file. (cdouglas via acmurthy) 

    HADOOP-3256. Encodes the job name used in the filename for history files.
    (Arun Murthy via ddas)

    HADOOP-3162. Ensure that comma-separated input paths are treated correctly
    as multiple input paths. (Amareshwari Sri Ramadasu via acmurthy)

    HADOOP-3263. Ensure that the job-history log file always follows the
    pattern of hostname_timestamp_jobid_username_jobname even if username
    and/or jobname are not specfied. This helps to avoid wrong assumptions
    made about the job-history log filename in jobhistory.jsp. (acmurthy) 

    HADOOP-3251. Fixes getFilesystemName in JobTracker and LocalJobRunner to
    use FileSystem.getUri instead of FileSystem.getName. (Arun Murthy via ddas)

    HADOOP-3237. Fixes TestDFSShell.testErrOutPut on Windows platform.
    (Mahadev Konar via ddas)

    HADOOP-3279. TaskTracker checks for SUCCEEDED task status in addition to 
    COMMIT_PENDING status when it fails maps due to lost map.
    (Devaraj Das)

    HADOOP-3286. Prevent collisions in gridmix output dirs by increasing the
    granularity of the timestamp. (Runping Qi via cdouglas)

    HADOOP-3285. Fix input split locality when the splits align to
    fs blocks. (omalley)

    HADOOP-3372. Fix heap management in streaming tests. (Arun Murthy via
    cdouglas)

    HADOOP-3031. Fix javac warnings in test classes. (cdouglas)

    HADOOP-3382. Fix memory leak when files are not cleanly closed (rangadi)

    HADOOP-3322. Fix to push MetricsRecord for rpc metrics. (Eric Yang via
    mukund)

Release 0.16.4 - 2008-05-05

  BUG FIXES

    HADOOP-3138. DFS mkdirs() should not throw an exception if the directory
    already exists. (rangadi via mukund)

    HADOOP-3294. Fix distcp to check the destination length and retry the copy
    if it doesn't match the src length. (Tsz Wo (Nicholas), SZE via mukund)

    HADOOP-3186. Fix incorrect permission checkding for mv and renameTo
    in HDFS. (Tsz Wo (Nicholas), SZE via mukund)

Release 0.16.3 - 2008-04-16

  BUG FIXES

    HADOOP-3010. Fix ConcurrentModificationException in ipc.Server.Responder.
    (rangadi)

    HADOOP-3154. Catch all Throwables from the SpillThread in MapTask, rather
    than IOExceptions only. (ddas via cdouglas)

    HADOOP-3159. Avoid file system cache being overwritten whenever
    configuration is modified. (Tsz Wo (Nicholas), SZE via hairong)

    HADOOP-3139. Remove the consistency check for the FileSystem cache in
    closeAll() that causes spurious warnings and a deadlock.
    (Tsz Wo (Nicholas), SZE via cdouglas)

    HADOOP-3195. Fix TestFileSystem to be deterministic.
    (Tsz Wo (Nicholas), SZE via cdouglas)

    HADOOP-3069. Primary name-node should not truncate image when transferring
    it from the secondary. (shv)

    HADOOP-3182. Change permissions of the job-submission directory to 777
    from 733 to ensure sharing of HOD clusters works correctly. (Tsz Wo
    (Nicholas), Sze and Amareshwari Sri Ramadasu via acmurthy) 

Release 0.16.2 - 2008-04-02

  BUG FIXES

    HADOOP-3011. Prohibit distcp from overwriting directories on the
    destination filesystem with files. (cdouglas)

    HADOOP-3033. The BlockReceiver thread in the datanode writes data to 
    the block file, changes file position (if needed) and flushes all by
    itself. The PacketResponder thread does not flush block file. (dhruba)

    HADOOP-2978. Fixes the JobHistory log format for counters.
    (Runping Qi via ddas)

    HADOOP-2985. Fixes LocalJobRunner to tolerate null job output path.
    Also makes the _temporary a constant in MRConstants.java.
    (Amareshwari Sriramadasu via ddas)

    HADOOP-3003. FileSystem cache key is updated after a 
    FileSystem object is created. (Tsz Wo (Nicholas), SZE via dhruba)

    HADOOP-3042. Updates the Javadoc in JobConf.getOutputPath to reflect 
    the actual temporary path. (Amareshwari Sriramadasu via ddas)

    HADOOP-3007. Tolerate mirror failures while DataNode is replicating
    blocks as it used to before. (rangadi)

    HADOOP-2944. Fixes a "Run on Hadoop" wizard NPE when creating a
    Location from the wizard. (taton)

    HADOOP-3049. Fixes a problem in MultiThreadedMapRunner to do with
    catching RuntimeExceptions. (Alejandro Abdelnur via ddas)

    HADOOP-3039. Fixes a problem to do with exceptions in tasks not
    killing jobs. (Amareshwari Sriramadasu via ddas)

    HADOOP-3027. Fixes a problem to do with adding a shutdown hook in
    FileSystem.  (Amareshwari Sriramadasu via ddas)

    HADOOP-3056. Fix distcp when the target is an empty directory by
    making sure the directory is created first. (cdouglas and acmurthy 
    via omalley)

    HADOOP-3070. Protect the trash emptier thread from null pointer
    exceptions. (Koji Noguchi via omalley)

    HADOOP-3084. Fix HftpFileSystem to work for zero-lenghth files.
    (cdouglas)

    HADOOP-3107. Fix NPE when fsck invokes getListings. (dhruba)

    HADOOP-3104. Limit MultithreadedMapRunner to have a fixed length queue
    between the RecordReader and the map threads. (Alejandro Abdelnur via
    omalley)

    HADOOP-2833. Do not use "Dr. Who" as the default user in JobClient. 
    A valid user name is required. (Tsz Wo (Nicholas), SZE via rangadi)

    HADOOP-3128. Throw RemoteException in setPermissions and setOwner of 
    DistributedFileSystem.  (shv via nigel)

Release 0.16.1 - 2008-03-13

  INCOMPATIBLE CHANGES

    HADOOP-2869. Deprecate SequenceFile.setCompressionType in favor of
    SequenceFile.createWriter, SequenceFileOutputFormat.setCompressionType,
    and JobConf.setMapOutputCompressionType. (Arun C Murthy via cdouglas)
    Configuration changes to hadoop-default.xml:
      deprecated io.seqfile.compression.type

  IMPROVEMENTS

    HADOOP-2371. User guide for file permissions in HDFS.
    (Robert Chansler via rangadi)

    HADOOP-3098. Allow more characters in user and group names while
    using -chown and -chgrp commands. (rangadi)
    
  BUG FIXES

    HADOOP-2789. Race condition in IPC Server Responder that could close
    connections early. (Raghu Angadi)
    
    HADOOP-2785. minor. Fix a typo in Datanode block verification 
    (Raghu Angadi)
    
    HADOOP-2788. minor. Fix help message for chgrp shell command (Raghu Angadi).
    
    HADOOP-1188. fstime file is updated when a storage directory containing
    namespace image becomes inaccessible. (shv)

    HADOOP-2787. An application can set a configuration variable named
    dfs.umask to set the umask that is used by DFS.
    (Tsz Wo (Nicholas), SZE via dhruba)

    HADOOP-2780. The default socket buffer size for DataNodes is 128K.
    (dhruba)

    HADOOP-2716. Superuser privileges for the Balancer.
    (Tsz Wo (Nicholas), SZE via shv)

    HADOOP-2754. Filter out .crc files from local file system listing.
    (Hairong Kuang via shv)

    HADOOP-2733. Fix compiler warnings in test code.
    (Tsz Wo (Nicholas), SZE via cdouglas)

    HADOOP-2725. Modify distcp to avoid leaving partially copied files at
    the destination after encountering an error. (Tsz Wo (Nicholas), SZE
    via cdouglas)

    HADOOP-2391. Cleanup job output directory before declaring a job as
    SUCCESSFUL. (Amareshwari Sri Ramadasu via ddas)

    HADOOP-2808. Minor fix to FileUtil::copy to mind the overwrite
    formal. (cdouglas)

    HADOOP-2683. Moving UGI out of the RPC Server.
    (Tsz Wo (Nicholas), SZE via shv)

    HADOOP-2814. Fix for NPE in datanode in unit test TestDataTransferProtocol.
    (Raghu Angadi via dhruba)

    HADOOP-2811. Dump of counters in job history does not add comma between
    groups. (runping via omalley)

    HADOOP-2735. Enables setting TMPDIR for tasks. 
    (Amareshwari Sri Ramadasu via ddas)

    HADOOP-2843. Fix protections on map-side join classes to enable derivation.
    (cdouglas via omalley)

    HADOOP-2840. Fix gridmix scripts to correctly invoke the java sort through
    the proper jar. (Mukund Madhugiri via cdouglas)

    HADOOP-2769.  TestNNThroughputBnechmark should not use a fixed port for
    the namenode http port. (omalley)

    HADOOP-2852. Update gridmix benchmark to avoid an artifically long tail.
    (cdouglas)

    HADOOP-2894. Fix a problem to do with tasktrackers failing to connect to
    JobTracker upon reinitialization. (Owen O'Malley via ddas).

    HADOOP-2903.  Fix exception generated by Metrics while using pushMetric().
    (girish vaitheeswaran via dhruba)

    HADOOP-2904.  Fix to RPC metrics to log the correct host name. 
    (girish vaitheeswaran via dhruba)

    HADOOP-2918.  Improve error logging so that dfs writes failure with
    "No lease on file" can be diagnosed. (dhruba)

    HADOOP-2923.  Add SequenceFileAsBinaryInputFormat, which was
    missed in the commit for HADOOP-2603. (cdouglas via omalley)

    HADOOP-2931. IOException thrown by DFSOutputStream had wrong stack
    trace in some cases. (Michael Bieniosek via rangadi)

    HADOOP-2883. Write failures and data corruptions on HDFS files.
    The write timeout is back to what it was on 0.15 release. Also, the
    datnodes flushes the block file buffered output stream before
    sending a positive ack for the packet back to the client. (dhruba)

    HADOOP-2756. NPE in DFSClient while closing DFSOutputStreams 
    under load. (rangadi)

    HADOOP-2958. Fixed FileBench which broke due to HADOOP-2391 which performs
    a check for existence of the output directory and a trivial bug in
    GenericMRLoadGenerator where min/max word lenghts were identical since
    they were looking at the same config variables (Chris Douglas via
    acmurthy) 

    HADOOP-2915. Fixed FileSystem.CACHE so that a username is included
    in the cache key. (Tsz Wo (Nicholas), SZE via nigel)

    HADOOP-2813. TestDU unit test uses its own directory to run its 
    sequence of tests.  (Mahadev Konar via dhruba)

Release 0.16.0 - 2008-02-07

  INCOMPATIBLE CHANGES

    HADOOP-1245.  Use the mapred.tasktracker.tasks.maximum value
    configured on each tasktracker when allocating tasks, instead of
    the value configured on the jobtracker. InterTrackerProtocol
    version changed from 5 to 6. (Michael Bieniosek via omalley)

    HADOOP-1843. Removed code from Configuration and JobConf deprecated by 
    HADOOP-785 and a minor fix to Configuration.toString. Specifically the 
    important change is that mapred-default.xml is no longer supported and 
    Configuration no longer supports the notion of default/final resources.
    (acmurthy) 

    HADOOP-1302.  Remove deprecated abacus code from the contrib directory.
    This also fixes a configuration bug in AggregateWordCount, so that the
    job now works.  (enis)

    HADOOP-2288.  Enhance FileSystem API to support access control.
    (Tsz Wo (Nicholas), SZE via dhruba)

    HADOOP-2184.  RPC Support for user permissions and authentication.
    (Raghu Angadi via dhruba)

    HADOOP-2185.  RPC Server uses any available port if the specified
    port is zero. Otherwise it uses the specified port. Also combines
    the configuration attributes for the servers' bind address and
    port from "x.x.x.x" and "y" to "x.x.x.x:y". 
    Deprecated configuration variables:
      dfs.info.bindAddress
      dfs.info.port
      dfs.datanode.bindAddress
      dfs.datanode.port
      dfs.datanode.info.bindAdress
      dfs.datanode.info.port
      dfs.secondary.info.bindAddress
      dfs.secondary.info.port
      mapred.job.tracker.info.bindAddress
      mapred.job.tracker.info.port
      mapred.task.tracker.report.bindAddress
      tasktracker.http.bindAddress
      tasktracker.http.port
    New configuration variables (post HADOOP-2404):
      dfs.secondary.http.address
      dfs.datanode.address
      dfs.datanode.http.address
      dfs.http.address
      mapred.job.tracker.http.address
      mapred.task.tracker.report.address
      mapred.task.tracker.http.address
    (Konstantin Shvachko via dhruba)

    HADOOP-2401.  Only the current leaseholder can abandon a block for
    a HDFS file.  ClientProtocol version changed from 20 to 21.
    (Tsz Wo (Nicholas), SZE via dhruba)

    HADOOP-2381.  Support permission information in FileStatus. Client
    Protocol version changed from 21 to 22.  (Raghu Angadi via dhruba)

    HADOOP-2110. Block report processing creates fewer transient objects.
    Datanode Protocol version changed from 10 to 11.  
    (Sanjay Radia via dhruba)
    
    HADOOP-2567.  Add FileSystem#getHomeDirectory(), which returns the
    user's home directory in a FileSystem as a fully-qualified path.
    FileSystem#getWorkingDirectory() is also changed to return a
    fully-qualified path, which can break applications that attempt
    to, e.g., pass LocalFileSystem#getWorkingDir().toString() directly
    to java.io methods that accept file names. (cutting)

    HADOOP-2514.  Change trash feature to maintain a per-user trash
    directory, named ".Trash" in the user's home directory.  The
    "fs.trash.root" parameter is no longer used.  Full source paths
    are also no longer reproduced within the trash.

    HADOOP-2012. Periodic data verification on Datanodes.
    (Raghu Angadi via dhruba)

    HADOOP-1707. The DFSClient does not use a local disk file to cache
    writes to a HDFS file. Changed Data Transfer Version from 7 to 8.
    (dhruba)

    HADOOP-2652. Fix permission issues for HftpFileSystem. This is an 
    incompatible change since distcp may not be able to copy files 
    from cluster A (compiled with this patch) to cluster B (compiled 
    with previous versions). (Tsz Wo (Nicholas), SZE via dhruba)

  NEW FEATURES

    HADOOP-1857.  Ability to run a script when a task fails to capture stack
    traces. (Amareshwari Sri Ramadasu via ddas)

    HADOOP-2299.  Defination of a login interface.  A simple implementation for
    Unix users and groups. (Hairong Kuang via dhruba)

    HADOOP-1652.  A utility to balance data among datanodes in a HDFS cluster.
    (Hairong Kuang via dhruba)

    HADOOP-2085.  A library to support map-side joins of consistently 
    partitioned and sorted data sets. (Chris Douglas via omalley)

    HADOOP-2336. Shell commands to modify file permissions. (rangadi)

    HADOOP-1298. Implement file permissions for HDFS.
    (Tsz Wo (Nicholas) & taton via cutting)

    HADOOP-2447. HDFS can be configured to limit the total number of 
    objects (inodes and blocks) in the file system. (dhruba)

    HADOOP-2487. Added an option to get statuses for all submitted/run jobs.
    This information can be used to develop tools for analysing jobs.
    (Amareshwari Sri Ramadasu via acmurthy)

    HADOOP-1873. Implement user permissions for Map/Reduce framework.
    (Hairong Kuang via shv)

    HADOOP-2532.  Add to MapFile a getClosest method that returns the key
    that comes just before if the key is not present.  (stack via tomwhite)
   
    HADOOP-1883. Add versioning to Record I/O. (Vivek Ratan via ddas)

    HADOOP-2603.  Add SeqeunceFileAsBinaryInputFormat, which reads
    sequence files as BytesWritable/BytesWritable regardless of the
    key and value types used to write the file. (cdouglas via omalley)

    HADOOP-2367. Add ability to profile a subset of map/reduce tasks and fetch
    the result to the local filesystem of the submitting application. Also
    includes a general IntegerRanges extension to Configuration for setting
    positive, ranged parameters. (Owen O'Malley via cdouglas)

  IMPROVEMENTS

    HADOOP-2045.  Change committer list on website to a table, so that
    folks can list their organization, timezone, etc.  (cutting)

    HADOOP-2058.  Facilitate creating new datanodes dynamically in
    MiniDFSCluster. (Hairong Kuang via dhruba)

    HADOOP-1855.  fsck verifies block placement policies and reports
    violations.  (Konstantin Shvachko via dhruba)

    HADOOP-1604.  An system administrator can finalize namenode upgrades 
    without running the cluster. (Konstantin Shvachko via dhruba)

    HADOOP-1839.  Link-ify the Pending/Running/Complete/Killed grid in
    jobdetails.jsp to help quickly narrow down and see categorized TIPs' 
    details via jobtasks.jsp. (Amar Kamat via acmurthy)

    HADOOP-1210.  Log counters in job history. (Owen O'Malley via ddas)

    HADOOP-1912. Datanode has two new commands COPY and REPLACE. These are
    needed for supporting data rebalance.  (Hairong Kuang via dhruba)

    HADOOP-2086. This patch adds the ability to add dependencies to a job
    (run via JobControl) after construction.  (Adrian Woodhead via ddas)

    HADOOP-1185. Support changing the logging level of a server without 
    restarting the server.  (Tsz Wo (Nicholas), SZE via dhruba)

    HADOOP-2134.  Remove developer-centric requirements from overview.html and
    keep it end-user focussed, specifically sections related to subversion and
    building Hadoop. (Jim Kellerman via acmurthy)

    HADOOP-1989. Support simulated DataNodes. This helps creating large virtual
    clusters for testing purposes.  (Sanjay Radia via dhruba)
    
    HADOOP-1274. Support different number of mappers and reducers per
    TaskTracker to  allow administrators to better configure and utilize
    heterogenous clusters. 
    Configuration changes to hadoop-default.xml:
      add mapred.tasktracker.map.tasks.maximum (default value of 2)
      add mapred.tasktracker.reduce.tasks.maximum (default value of 2)
      remove mapred.tasktracker.tasks.maximum (deprecated for 0.16.0)
    (Amareshwari Sri Ramadasu via acmurthy) 

    HADOOP-2104. Adds a description to the ant targets. This makes the 
    output of "ant -projecthelp" sensible. (Chris Douglas via ddas)

    HADOOP-2127. Added a pipes sort example to benchmark trivial pipes
    application versus trivial java application. (omalley via acmurthy)

    HADOOP-2113. A new shell command "dfs -text" to view the contents of
    a gziped or SequenceFile. (Chris Douglas via dhruba)

    HADOOP-2207.  Add a "package" target for contrib modules that
    permits each to determine what files are copied into release
    builds.  (stack via cutting)

    HADOOP-1984. Makes the backoff for failed fetches exponential. 
    Earlier, it was a random backoff from an interval. 
    (Amar Kamat via ddas)

    HADOOP-1327.  Include website documentation for streaming. (Rob Weltman
    via omalley)

    HADOOP-2000.  Rewrite NNBench to measure namenode performance accurately.
    It now uses the map-reduce framework for load generation.
    (Mukund Madhugiri via dhruba)

    HADOOP-2248. Speeds up the framework w.r.t Counters. Also has API
    updates to the Counters part. (Owen O'Malley via ddas)

    HADOOP-2326. The initial block report at Datanode startup time has
    a random backoff period.  (Sanjay Radia via dhruba)

    HADOOP-2432. HDFS includes the name of the file while throwing 
    "File does not exist"  exception. (Jim Kellerman via dhruba)

    HADOOP-2457. Added a 'forrest.home' property to the 'docs' target in
    build.xml. (acmurthy) 

    HADOOP-2149.  A new benchmark for three name-node operation: file create, 
    open, and block report, to evaluate the name-node performance 
    for optimizations or new features. (Konstantin Shvachko via shv)

    HADOOP-2466. Change FileInputFormat.computeSplitSize to a protected
    non-static method to allow sub-classes to provide alternate
    implementations. (Alejandro Abdelnur via acmurthy) 

    HADOOP-2425. Change TextOutputFormat to handle Text specifically for better
    performance. Make NullWritable implement Comparable. Make TextOutputFormat
    treat NullWritable like null. (omalley)

    HADOOP-1719. Improves the utilization of shuffle copier threads.
    (Amar Kamat via ddas)
 
    HADOOP-2390. Added documentation for user-controls for intermediate
    map-outputs & final job-outputs and native-hadoop libraries. (acmurthy) 
 
    HADOOP-1660. Add the cwd of the map/reduce task to the java.library.path
    of the child-jvm to support loading of native libraries distributed via
    the DistributedCache. (acmurthy)
 
    HADOOP-2285. Speeds up TextInputFormat. Also includes updates to the
    Text API. (Owen O'Malley via cdouglas)

    HADOOP-2233. Adds a generic load generator for modeling MR jobs. (cdouglas)

    HADOOP-2369. Adds a set of scripts for simulating a mix of user map/reduce
    workloads. (Runping Qi via cdouglas)

    HADOOP-2547. Removes use of a 'magic number' in build.xml. 
    (Hrishikesh via nigel)

    HADOOP-2268. Fix org.apache.hadoop.mapred.jobcontrol classes to use the
    List/Map interfaces rather than concrete ArrayList/HashMap classes
    internally. (Adrian Woodhead via acmurthy)

    HADOOP-2406. Add a benchmark for measuring read/write performance through
    the InputFormat interface, particularly with compression. (cdouglas)

    HADOOP-2131. Allow finer-grained control over speculative-execution. Now
    users can set it for maps and reduces independently.
    Configuration changes to hadoop-default.xml:
      deprecated mapred.speculative.execution
      add mapred.map.tasks.speculative.execution
      add mapred.reduce.tasks.speculative.execution
    (Amareshwari Sri Ramadasu via acmurthy) 
      
    HADOOP-1965. Interleave sort/spill in teh map-task along with calls to the
    Mapper.map method. This is done by splitting the 'io.sort.mb' buffer into
    two and using one half for collecting map-outputs and the other half for
    sort/spill. (Amar Kamat via acmurthy)
    
    HADOOP-2464. Unit tests for chmod, chown, and chgrp using DFS.
    (Raghu Angadi)

    HADOOP-1876. Persist statuses of completed jobs in HDFS so that the
    JobClient can query and get information about decommissioned jobs and also
    across JobTracker restarts.
    Configuration changes to hadoop-default.xml:
      add mapred.job.tracker.persist.jobstatus.active (default value of false)
      add mapred.job.tracker.persist.jobstatus.hours (default value of 0)
      add mapred.job.tracker.persist.jobstatus.dir (default value of
                                                    /jobtracker/jobsInfo)
    (Alejandro Abdelnur via acmurthy) 

    HADOOP-2077. Added version and build information to STARTUP_MSG for all
    hadoop daemons to aid error-reporting, debugging etc. (acmurthy) 

    HADOOP-2398. Additional instrumentation for NameNode and RPC server.
    Add support for accessing instrumentation statistics via JMX.
    (Sanjay radia via dhruba)

    HADOOP-2449. A return of the non-MR version of NNBench.
    (Sanjay Radia via shv)

    HADOOP-1989. Remove 'datanodecluster' command from bin/hadoop.
    (Sanjay Radia via shv)

    HADOOP-1742. Improve JavaDoc documentation for ClientProtocol, DFSClient,
    and FSNamesystem. (Konstantin Shvachko)

    HADOOP-2298. Add Ant target for a binary-only distribution.
    (Hrishikesh via nigel)

    HADOOP-2509. Add Ant target for Rat report (Apache license header
    reports).  (Hrishikesh via nigel)

    HADOOP-2469.  WritableUtils.clone should take a Configuration
    instead of a JobConf. (stack via omalley)

    HADOOP-2659. Introduce superuser permissions for admin operations.
    (Tsz Wo (Nicholas), SZE via shv)

    HADOOP-2596. Added a SequenceFile.createWriter api which allows the user
    to specify the blocksize, replication factor and the buffersize to be
    used for the underlying HDFS file. (Alejandro Abdelnur via acmurthy) 

    HADOOP-2431. Test HDFS File Permissions. (Hairong Kuang via shv)

    HADOOP-2232. Add an option to disable Nagle's algorithm in the IPC stack.
    (Clint Morgan via cdouglas)

    HADOOP-2342. Created a micro-benchmark for measuring 
    local-file versus hdfs reads. (Owen O'Malley via nigel)

    HADOOP-2529. First version of HDFS User Guide. (Raghu Angadi)

    HADOOP-2690. Add jar-test target to build.xml, separating compilation
    and packaging of the test classes. (Enis Soztutar via cdouglas)

  OPTIMIZATIONS

    HADOOP-1898.  Release the lock protecting the last time of the last stack
    dump while the dump is happening. (Amareshwari Sri Ramadasu via omalley)

    HADOOP-1900. Makes the heartbeat and task event queries interval 
    dependent on the cluster size.  (Amareshwari Sri Ramadasu via ddas)

    HADOOP-2208. Counter update frequency (from TaskTracker to JobTracker) is 
    capped at 1 minute.  (Amareshwari Sri Ramadasu via ddas)

    HADOOP-2284. Reduce the number of progress updates during the sorting in 
    the map task. (Amar Kamat via ddas)

  BUG FIXES

    HADOOP-2583.  Fixes a bug in the Eclipse plug-in UI to edit locations.
    Plug-in version is now synchronized with Hadoop version.

    HADOOP-2100.  Remove faulty check for existence of $HADOOP_PID_DIR and let
    'mkdir -p' check & create it. (Michael Bieniosek via acmurthy)

    HADOOP-1642.  Ensure jobids generated by LocalJobRunner are unique to
    avoid collissions and hence job-failures. (Doug Cutting via acmurthy) 

    HADOOP-2096.  Close open file-descriptors held by streams while localizing
    job.xml in the JobTracker and while displaying it on the webui in 
    jobconf.jsp. (Amar Kamat via acmurthy)

    HADOOP-2098.  Log start & completion of empty jobs to JobHistory, which
    also ensures that we close the file-descriptor of the job's history log 
    opened during job-submission. (Amar Kamat via acmurthy)

    HADOOP-2112.  Adding back changes to build.xml lost while reverting
    HADOOP-1622 i.e. http://svn.apache.org/viewvc?view=rev&revision=588771.
    (acmurthy)

    HADOOP-2089.  Fixes the command line argument handling to handle multiple
    -cacheArchive in Hadoop streaming.  (Lohit Vijayarenu via ddas)

    HADOOP-2071.  Fix StreamXmlRecordReader to use a BufferedInputStream
    wrapped over the DFSInputStream since mark/reset aren't supported by
    DFSInputStream anymore. (Lohit Vijayarenu via acmurthy)

    HADOOP-1348.  Allow XML comments inside configuration files. 
    (Rajagopal Natarajan and Enis Soztutar via enis)

    HADOOP-1952.  Improve handling of invalid, user-specified classes while
    configuring streaming jobs such as combiner, input/output formats etc.
    Now invalid options are caught, logged and jobs are failed early. (Lohit
    Vijayarenu via acmurthy)

    HADOOP-2151. FileSystem.globPaths validates the list of Paths that
    it returns.  (Lohit Vijayarenu via dhruba)

    HADOOP-2121. Cleanup DFSOutputStream when the stream encountered errors
    when Datanodes became full.  (Raghu Angadi via dhruba)

    HADOOP-1130. The FileSystem.closeAll() method closes all existing
    DFSClients.  (Chris Douglas via dhruba)

    HADOOP-2204. DFSTestUtil.waitReplication was not waiting for all replicas
    to get created, thus causing unit test failure.
    (Raghu Angadi via dhruba)

    HADOOP-2078. An zero size file may have no blocks associated with it.
    (Konstantin Shvachko via dhruba)

    HADOOP-2212. ChecksumFileSystem.getSumBufferSize might throw 
    java.lang.ArithmeticException. The fix is to initialize bytesPerChecksum
    to 0.  (Michael Bieniosek via ddas)

    HADOOP-2216.  Fix jobtasks.jsp to ensure that it first collects the
    taskids which satisfy the filtering criteria and then use that list to
    print out only the required task-reports, previously it was oblivious to
    the filtering and hence used the wrong index into the array of task-reports. 
    (Amar Kamat via acmurthy)

    HADOOP-2272.  Fix findbugs target to reflect changes made to the location
    of the streaming jar file by HADOOP-2207.  (Adrian Woodhead via nigel)

    HADOOP-2244.  Fixes the MapWritable.readFields to clear the instance 
    field variable every time readFields is called. (Michael Stack via ddas).

    HADOOP-2245.  Fixes LocalJobRunner to include a jobId in the mapId. Also,  
    adds a testcase for JobControl. (Adrian Woodhead via ddas).

    HADOOP-2275. Fix erroneous detection of corrupted file when namenode 
    fails to allocate any datanodes for newly allocated block.
    (Dhruba Borthakur via dhruba)

    HADOOP-2256. Fix a buf in the namenode that could cause it to encounter
    an infinite loop while deleting excess replicas that were created by 
    block rebalancing.  (Hairong Kuang via dhruba)

    HADOOP-2209. SecondaryNamenode process exits if it encounters exceptions 
    that it cannot handle.  (Dhruba Borthakur via dhruba)

    HADOOP-2314. Prevent TestBlockReplacement from occasionally getting
    into an infinite loop.  (Hairong Kuang via dhruba)

    HADOOP-2300. This fixes a bug where mapred.tasktracker.tasks.maximum
    would be ignored even if it was set in hadoop-site.xml.
    (Amareshwari Sri Ramadasu via ddas)

    HADOOP-2349.  Improve code layout in file system transaction logging code.
    (Tsz Wo (Nicholas), SZE via dhruba)

    HADOOP-2368.  Fix unit tests on Windows.
    (Tsz Wo (Nicholas), SZE via dhruba)

    HADOOP-2363.  This fix allows running multiple instances of the unit test
    in parallel. The bug was introduced in HADOOP-2185 that changed
    port-rolling behaviour.  (Konstantin Shvachko via dhruba)

    HADOOP-2271.  Fix chmod task to be non-parallel. (Adrian Woodhead via
    omalley)

    HADOOP-2313.  Fail the build if building libhdfs fails. (nigel via omalley)

    HADOOP-2359.  Remove warning for interruptted exception when closing down
    minidfs. (dhruba via omalley)

    HADOOP-1841. Prevent slow clients from consuming threads in the NameNode. 
    (dhruba)
    
    HADOOP-2323. JobTracker.close() should not print stack traces for
    normal exit.  (jimk via cutting)

    HADOOP-2376. Prevents sort example from overriding the number of maps.
    (Owen O'Malley via ddas)

    HADOOP-2434. FSDatasetInterface read interface causes HDFS reads to occur 
    in 1 byte chunks, causing performance degradation.
    (Raghu Angadi via dhruba)

    HADOOP-2459. Fix package target so that src/docs/build files are not
    included in the release.  (nigel)

    HADOOP-2215.  Fix documentation in cluster_setup.html &
    mapred_tutorial.html reflect that mapred.tasktracker.tasks.maximum has
    been superceeded by mapred.tasktracker.{map|reduce}.tasks.maximum. 
    (Amareshwari Sri Ramadasu via acmurthy)

    HADOOP-2459. Fix package target so that src/docs/build files are not
    included in the release.  (nigel)

    HADOOP-2352. Remove AC_CHECK_LIB for libz and liblzo to ensure that
    libhadoop.so doesn't have a dependency on them. (acmurthy) 

    HADOOP-2453. Fix the configuration for wordcount-simple example in Hadoop 
    Pipes which currently produces an XML parsing error. (Amareshwari Sri
    Ramadasu via acmurthy)

    HADOOP-2476. Unit test failure while reading permission bits of local
    file system (on Windows) fixed.  (Raghu Angadi via dhruba)

    HADOOP-2247.  Fine-tune the strategies for killing mappers and reducers
    due to failures while fetching map-outputs. Now the map-completion times
    and number of currently running reduces are taken into account by the
    JobTracker before  killing the mappers, while the progress made by the
    reducer and the number of fetch-failures vis-a-vis total number of
    fetch-attempts are taken into account before teh reducer kills itself.
    (Amar Kamat via acmurthy)
    
    HADOOP-2452. Fix eclipse plug-in build.xml to refers to the right
    location where hadoop-*-core.jar is generated. (taton)

    HADOOP-2492. Additional debugging in the rpc server to better 
    diagnose ConcurrentModificationException. (dhruba)

    HADOOP-2344. Enhance the utility for executing shell commands to read the
    stdout/stderr streams while waiting for the command to finish (to free up
    the buffers). Also, this patch throws away stderr of the DF utility.
    @deprecated 
      org.apache.hadoop.fs.ShellCommand for org.apache.hadoop.util.Shell
      org.apache.hadoop.util.ShellUtil for 
        org.apache.hadoop.util.Shell.ShellCommandExecutor
    (Amar Kamat via acmurthy)

    HADOOP-2511. Fix a javadoc warning in org.apache.hadoop.util.Shell
    introduced by HADOOP-2344. (acmurthy) 

    HADOOP-2442. Fix TestLocalFileSystemPermission.testLocalFSsetOwner
    to work on more platforms. (Raghu Angadi via nigel)

    HADOOP-2488. Fix a regression in random read performance.
    (Michael Stack via rangadi)

    HADOOP-2523. Fix TestDFSShell.testFilePermissions on Windows.
    (Raghu Angadi via nigel)

    HADOOP-2535. Removed support for deprecated mapred.child.heap.size and
    fixed some indentation issues in TaskRunner. (acmurthy)
    Configuration changes to hadoop-default.xml:
      remove mapred.child.heap.size

    HADOOP-2512. Fix error stream handling in Shell. Use exit code to
    detect shell command errors in RawLocalFileSystem. (Raghu Angadi)

    HADOOP-2446. Fixes TestHDFSServerPorts and TestMRServerPorts so they
    do not rely on statically configured ports and cleanup better. (nigel)

    HADOOP-2537. Make build process compatible with Ant 1.7.0.
    (Hrishikesh via nigel)

    HADOOP-1281. Ensure running tasks of completed map TIPs (e.g. speculative
    tasks) are killed as soon as the TIP completed. (acmurthy)

    HADOOP-2571. Suppress a suprious warning in test code. (cdouglas)

    HADOOP-2481. NNBench report its progress periodically.
    (Hairong Kuang via dhruba)

    HADOOP-2601. Start name-node on a free port for TestNNThroughputBenchmark.
    (Konstantin Shvachko)

    HADOOP-2494.  Set +x on contrib/*/bin/* in packaged tar bundle.
    (stack via tomwhite)

    HADOOP-2605. Remove bogus leading slash in task-tracker report bindAddress.
    (Konstantin Shvachko)
    
    HADOOP-2620. Trivial. 'bin/hadoop fs -help' did not list chmod, chown, and
    chgrp. (Raghu Angadi)

    HADOOP-2614. The DFS WebUI accesses are configured to be from the user
    specified by dfs.web.ugi.  (Tsz Wo (Nicholas), SZE via dhruba)

    HADOOP-2543. Implement a "no-permission-checking" mode for smooth
    upgrade from a pre-0.16 install of HDFS.
    (Hairong Kuang via dhruba)

    HADOOP-290. A DataNode log message now prints the target of a replication
    request correctly. (dhruba)

    HADOOP-2538. Redirect to a warning, if plaintext parameter is true but 
    the filter parameter is not given in TaskLogServlet.  
    (Michael Bieniosek via enis)

    HADOOP-2582. Prevent 'bin/hadoop fs -copyToLocal' from creating
    zero-length files when the src does not exist.
    (Lohit Vijayarenu via cdouglas)

    HADOOP-2189. Incrementing user counters should count as progress. (ddas)

    HADOOP-2649. The NameNode periodically computes replication work for
    the datanodes. The periodicity of this computation is now configurable.
    (dhruba)

    HADOOP-2549. Correct disk size computation so that data-nodes could switch 
    to other local drives if current is full. (Hairong Kuang via shv)

    HADOOP-2633. Fsck should call name-node methods directly rather than 
    through rpc. (Tsz Wo (Nicholas), SZE via shv)

    HADOOP-2687. Modify a few log message generated by dfs client to be
    logged only at INFO level. (stack via dhruba)

    HADOOP-2402. Fix BlockCompressorStream to ensure it buffers data before
    sending it down to the compressor so that each write call doesn't
    compress. (Chris Douglas via acmurthy) 

    HADOOP-2645. The Metrics initialization code does not throw
    exceptions when servers are restarted by MiniDFSCluster.
    (Sanjay Radia via dhruba)

    HADOOP-2691. Fix a race condition that was causing the DFSClient
    to erroneously remove a good datanode from a pipeline that actually
    had another datanode that was bad. (dhruba)

    HADOOP-1195. All code in FSNamesystem checks the return value
    of getDataNode for null before using it. (dhruba)

    HADOOP-2640. Fix a bug in MultiFileSplitInputFormat that was always
    returning 1 split in some circumstances. (Enis Soztutar via nigel)

    HADOOP-2626. Fix paths with special characters to work correctly
    with the local filesystem.  (Thomas Friol via cutting)

    HADOOP-2646. Fix SortValidator to work with fully-qualified 
    working directories.  (Arun C Murthy via nigel)

    HADOOP-2092. Added a ping mechanism to the pipes' task to periodically
    check if the parent Java task is running, and exit if the parent isn't
    alive and responding. (Amareshwari Sri Ramadasu via acmurthy) 

    HADOOP-2714. TestDecommission failed on windows because the replication
    request was timing out. (dhruba)

    HADOOP-2576. Namenode performance degradation over time triggered by
    large heartbeat interval. (Raghu Angadi)

    HADOOP-2713. TestDatanodeDeath failed on windows because the replication
    request was timing out. (dhruba)

    HADOOP-2639. Fixes a problem to do with incorrect maintenance of values 
    for runningMapTasks/runningReduceTasks. (Amar Kamat and Arun Murthy 
    via ddas)

    HADOOP-2723. Fixed the check for checking whether to do user task
    profiling. (Amareshwari Sri Ramadasu via omalley)

    HADOOP-2734. Link forrest docs to new http://hadoop.apache.org
    (Doug Cutting via nigel)

    HADOOP-2641. Added Apache license headers to 95 files. (nigel)

    HADOOP-2732. Fix bug in path globbing.  (Hairong Kuang via nigel)

    HADOOP-2404. Fix backwards compatability with hadoop-0.15 configuration
    files that was broken by HADOOP-2185. (omalley)

    HADOOP-2755. Fix fsck performance degradation because of permissions 
    issue.  (Tsz Wo (Nicholas), SZE via dhruba)

    HADOOP-2768. Fix performance regression caused by HADOOP-1707.
    (dhruba borthakur via nigel)

    HADOOP-3108. Fix NPE in setPermission and setOwner. (shv)

Release 0.15.3 - 2008-01-18

  BUG FIXES

    HADOOP-2562. globPaths supports {ab,cd}.  (Hairong Kuang via dhruba)

    HADOOP-2540. fsck reports missing blocks incorrectly. (dhruba)

    HADOOP-2570. "work" directory created unconditionally, and symlinks
    created from the task cwds.

    HADOOP-2574. Fixed mapred_tutorial.xml to correct minor errors with the
    WordCount examples. (acmurthy) 

Release 0.15.2 - 2008-01-02

  BUG FIXES

    HADOOP-2246.  Moved the changelog for HADOOP-1851 from the NEW FEATURES 
    section to the INCOMPATIBLE CHANGES section. (acmurthy)

    HADOOP-2238.  Fix TaskGraphServlet so that it sets the content type of 
    the response appropriately.  (Paul Saab via enis)

    HADOOP-2129.  Fix so that distcp works correctly when source is
    HDFS but not the default filesystem.  HDFS paths returned by the
    listStatus() method are now fully-qualified.  (cutting)

    HADOOP-2378.  Fixes a problem where the last task completion event would
    get created after the job completes. (Alejandro Abdelnur via ddas)

    HADOOP-2228.  Checks whether a job with a certain jobId is already running
    and then tries to create the JobInProgress object. 
    (Johan Oskarsson via ddas)

    HADOOP-2422.  dfs -cat multiple files fail with 'Unable to write to 
    output stream'.  (Raghu Angadi via dhruba)

    HADOOP-2460.  When the namenode encounters ioerrors on writing a
    transaction log, it stops writing new transactions to that one.
    (Raghu Angadi via dhruba)

    HADOOP-2227.  Use the LocalDirAllocator uniformly for handling all of the
    temporary storage required for a given task. It also implies that
    mapred.local.dir.minspacestart is handled by checking if there is enough
    free-space on any one of the available disks. (Amareshwari Sri Ramadasu
    via acmurthy)

    HADOOP-2437.  Fix the LocalDirAllocator to choose the seed for the
    round-robin disk selections randomly. This helps in spreading data across
    multiple partitions much better. (acmurhty)

    HADOOP-2486. When the list of files from the InMemoryFileSystem is obtained
    for merging, this patch will ensure that only those files whose checksums
    have also got created (renamed) are returned. (ddas)

    HADOOP-2456. Hardcode English locale to prevent NumberFormatException
    from occurring when starting the NameNode with certain locales.
    (Matthias Friedrich via nigel)

  IMPROVEMENTS

    HADOOP-2160.  Remove project-level, non-user documentation from
    releases, since it's now maintained in a separate tree.  (cutting)

    HADOOP-1327.  Add user documentation for streaming.  (cutting)

    HADOOP-2382.  Add hadoop-default.html to subversion. (cutting)

    HADOOP-2158. hdfsListDirectory calls FileSystem.listStatus instead
    of FileSystem.listPaths. This reduces the number of RPC calls on the
    namenode, thereby improving scalability.  (Christian Kunz via dhruba)

Release 0.15.1 - 2007-11-27

  INCOMPATIBLE CHANGES

    HADOOP-713.  Reduce CPU usage on namenode while listing directories.
    FileSystem.listPaths does not return the size of the entire subtree.
    Introduced a new API ClientProtocol.getContentLength that returns the
    size of the subtree. (Dhruba Borthakur via dhruba)

  IMPROVEMENTS

    HADOOP-1917.  Addition of guides/tutorial for better overall
    documentation for Hadoop. Specifically: 
    * quickstart.html is targetted towards first-time users and helps them 
      setup a single-node cluster and play with Hadoop. 
    * cluster_setup.html helps admins to configure and setup non-trivial
      hadoop clusters.
    * mapred_tutorial.html is a comprehensive Map-Reduce tutorial. 
    (acmurthy) 

  BUG FIXES

    HADOOP-2174.  Removed the unnecessary Reporter.setStatus call from
    FSCopyFilesMapper.close which led to a NPE since the reporter isn't valid
    in the close method. (Chris Douglas via acmurthy) 

    HADOOP-2172.  Restore performance of random access to local files
    by caching positions of local input streams, avoiding a system
    call. (cutting)

    HADOOP-2205.  Regenerate the Hadoop website since some of the changes made
    by HADOOP-1917 weren't correctly copied over to the trunk/docs directory. 
    Also fixed a couple of minor typos and broken links. (acmurthy)

Release 0.15.0 - 2007-11-2

  INCOMPATIBLE CHANGES

    HADOOP-1708.  Make files appear in namespace as soon as they are
    created.  (Dhruba Borthakur via dhruba)

    HADOOP-999.  A HDFS Client immediately informs the NameNode of a new
    file creation.  ClientProtocol version changed from 14 to 15.
    (Tsz Wo (Nicholas), SZE via dhruba)

    HADOOP-932.  File locking interfaces and implementations (that were
    earlier deprecated) are removed.  Client Protocol version changed 
    from 15 to 16.  (Raghu Angadi via dhruba)

    HADOOP-1621.  FileStatus is now a concrete class and FileSystem.listPaths
    is deprecated and replaced with listStatus. (Chris Douglas via omalley)

    HADOOP-1656.  The blockSize of a file is stored persistently in the file
    inode. (Dhruba Borthakur via dhruba)

    HADOOP-1838.  The blocksize of files created with an earlier release is
    set to the default block size.  (Dhruba Borthakur via dhruba)

    HADOOP-785.  Add support for 'final' Configuration parameters,
    removing support for 'mapred-default.xml', and changing
    'hadoop-site.xml' to not override other files.  Now folks should
    generally use 'hadoop-site.xml' for all configurations.  Values
    with a 'final' tag may not be overridden by subsequently loaded
    configuration files, e.g., by jobs.  (Arun C. Murthy via cutting)

    HADOOP-1846. DatanodeReport in ClientProtocol can report live 
    datanodes, dead datanodes or all datanodes. Client Protocol version
    changed from 17 to 18.  (Hairong Kuang via dhruba)

    HADOOP-1851.  Permit specification of map output compression type
    and codec, independent of the final output's compression
    parameters.  (Arun C Murthy via cutting)

    HADOOP-1819.  Jobtracker cleanups, including binding ports before
    clearing state directories, so that inadvertently starting a
    second jobtracker doesn't trash one that's already running. Removed
    method JobTracker.getTracker() because the static variable, which
    stored the value caused initialization problems.
    (omalley via cutting)

  NEW FEATURES

    HADOOP-89.  A client can access file data even before the creator
    has closed the file. Introduce a new command "tail" from dfs shell.
    (Dhruba Borthakur via dhruba)

    HADOOP-1636.  Allow configuration of the number of jobs kept in
    memory by the JobTracker.  (Michael Bieniosek via omalley)

    HADOOP-1667.  Reorganize CHANGES.txt into sections to make it
    easier to read.  Also remove numbering, to make merging easier.
    (cutting)

    HADOOP-1610.  Add metrics for failed tasks.
    (Devaraj Das via tomwhite)

    HADOOP-1767.  Add "bin/hadoop job -list" sub-command. (taton via cutting)

    HADOOP-1351.  Add "bin/hadoop job [-fail-task|-kill-task]" sub-commands
    to terminate a particular task-attempt. (Enis Soztutar via acmurthy)

    HADOOP-1880. SleepJob : An example job that sleeps at each map and 
    reduce task. (enis)

    HADOOP-1809. Add a link in web site to #hadoop IRC channel. (enis)

    HADOOP-1894. Add percentage graphs and mapred task completion graphs 
    to Web User Interface. Users not using Firefox may install a plugin to 
    their browsers to see svg graphics. (enis)

    HADOOP-1914. Introduce a new NamenodeProtocol to allow secondary 
    namenodes and rebalancing processes to communicate with a primary 
    namenode.  (Hairong Kuang via dhruba)

    HADOOP-1963.  Add a FileSystem implementation for the Kosmos
    Filesystem (KFS).  (Sriram Rao via cutting)

    HADOOP-1822.  Allow the specialization and configuration of socket
    factories. Provide a StandardSocketFactory, and a SocksSocketFactory to
    allow the use of SOCKS proxies. (taton).

    HADOOP-1968. FileSystem supports wildcard input syntax "{ }".
    (Hairong Kuang via dhruba)

    HADOOP-2566. Add globStatus method to the FileSystem interface
    and deprecate globPath and listPath. (Hairong Kuang via hairong)

  OPTIMIZATIONS

    HADOOP-1910.  Reduce the number of RPCs that DistributedFileSystem.create()
    makes to the namenode. (Raghu Angadi via dhruba)

    HADOOP-1565.  Reduce memory usage of NameNode by replacing 
    TreeMap in HDFS Namespace with ArrayList.  
    (Dhruba Borthakur via dhruba)

    HADOOP-1743.  Change DFS INode from a nested class to standalone
    class, with specialized subclasses for directories and files, to
    save memory on the namenode.  (Konstantin Shvachko via cutting)

    HADOOP-1759.  Change file name in INode from String to byte[],
    saving memory on the namenode. (Konstantin Shvachko via cutting)

    HADOOP-1766.  Save memory in namenode by having BlockInfo extend
    Block, and replace many uses of Block with BlockInfo.
    (Konstantin Shvachko via cutting)

    HADOOP-1687.  Save memory in namenode by optimizing BlockMap
    representation.  (Konstantin Shvachko via cutting)

    HADOOP-1774. Remove use of INode.parent in Block CRC upgrade.
    (Raghu Angadi via dhruba)

    HADOOP-1788.  Increase the buffer size on the Pipes command socket.
    (Amareshwari Sri Ramadasu and Christian Kunz via omalley)

  BUG FIXES

    HADOOP-1946.  The Datanode code does not need to invoke du on
    every heartbeat.  (Hairong Kuang via dhruba)

    HADOOP-1935. Fix a NullPointerException in internalReleaseCreate.
    (Dhruba Borthakur)

    HADOOP-1933. The nodes listed in include and exclude files 
    are always listed in the datanode report.
    (Raghu Angadi via dhruba)

    HADOOP-1953. The job tracker should wait beteween calls to try and delete 
    the system directory (Owen O'Malley via devaraj)

    HADOOP-1932. TestFileCreation fails with message saying filestatus.dat
    is of incorrect size.  (Dhruba Borthakur via dhruba)

    HADOOP-1573. Support for 0 reducers in PIPES. 
    (Owen O'Malley via devaraj)

    HADOOP-1500. Fix typographical errors in the DFS WebUI.
    (Nigel Daley via dhruba)

    HADOOP-1076. Periodic checkpoint can continue even if an earlier
    checkpoint encountered an error.  (Dhruba Borthakur via dhruba)

    HADOOP-1887. The Namenode encounters an ArrayIndexOutOfBoundsException
    while listing a directory that had a file that was
    being actively written to.  (Dhruba Borthakur via dhruba)

    HADOOP-1904. The Namenode encounters an exception because the
    list of blocks per datanode-descriptor was corrupted.
    (Konstantin Shvachko via dhruba)

    HADOOP-1762. The Namenode fsimage does not contain a list of
    Datanodes.  (Raghu Angadi via dhruba)

    HADOOP-1890. Removed debugging prints introduced by HADOOP-1774.
    (Raghu Angadi via dhruba)

    HADOOP-1763. Too many lost task trackers on large clusters due to
    insufficient number of RPC handler threads on the JobTracker.
    (Devaraj Das)

    HADOOP-1463.  HDFS report correct usage statistics for disk space
    used by HDFS.  (Hairong Kuang via dhruba)

    HADOOP-1692.  In DFS ant task, don't cache the Configuration.
    (Chris Douglas via cutting)

    HADOOP-1726.  Remove lib/jetty-ext/ant.jar. (omalley)

    HADOOP-1772.  Fix hadoop-daemon.sh script to get correct hostname
    under Cygwin.  (Tsz Wo (Nicholas), SZE via cutting)

    HADOOP-1749.  Change TestDFSUpgrade to sort files, fixing sporadic
    test failures.  (Enis Soztutar via cutting)

    HADOOP-1748.  Fix tasktracker to be able to launch tasks when log
    directory is relative.  (omalley via cutting)

    HADOOP-1775.  Fix a NullPointerException and an
    IllegalArgumentException in MapWritable.
    (Jim Kellerman via cutting)

    HADOOP-1795.  Fix so that jobs can generate output file names with
    special characters.  (Fr??d??ric Bertin via cutting)

    HADOOP-1810.  Fix incorrect value type in MRBench (SmallJobs)
    (Devaraj Das via tomwhite)

    HADOOP-1806.  Fix ant task to compile again, also fix default
    builds to compile ant tasks.  (Chris Douglas via cutting)

    HADOOP-1758.  Fix escape processing in librecordio to not be
    quadratic.  (Vivek Ratan via cutting)

    HADOOP-1817.  Fix MultiFileSplit to read and write the split
    length, so that it is not always zero in map tasks.
    (Thomas Friol via cutting)

    HADOOP-1853.  Fix contrib/streaming to accept multiple -cacheFile
    options.  (Prachi Gupta via cutting)

    HADOOP-1818. Fix MultiFileInputFormat so that it does not return 
    empty splits when numPaths < numSplits.  (Thomas Friol via enis)

    HADOOP-1840. Fix race condition which leads to task's diagnostic
    messages getting lost. (acmurthy) 

    HADOOP-1885. Fix race condition in MiniDFSCluster shutdown.
    (Chris Douglas via nigel)

    HADOOP-1889.  Fix path in EC2 scripts for building your own AMI.
    (tomwhite)

    HADOOP-1892.  Fix a NullPointerException in the JobTracker when
    trying to fetch a task's diagnostic messages from the JobClient.
    (Amar Kamat via acmurthy)

    HADOOP-1897.  Completely remove about.html page from the web site.
    (enis)

    HADOOP-1907.  Fix null pointer exception when getting task diagnostics
    in JobClient. (Christian Kunz via omalley)

    HADOOP-1882.  Remove spurious asterisks from decimal number displays.
    (Raghu Angadi via cutting)

    HADOOP-1783.  Make S3 FileSystem return Paths fully-qualified with
    scheme and host.  (tomwhite)

    HADOOP-1925.  Make pipes' autoconf script look for libsocket and libnsl, so
    that it can compile under Solaris. (omalley)

    HADOOP-1940.  TestDFSUpgradeFromImage must shut down its MiniDFSCluster.
    (Chris Douglas via nigel)

    HADOOP-1930.  Fix the blame for failed fetchs on the right host. (Arun C.
    Murthy via omalley)

    HADOOP-1934.  Fix the platform name on Mac to use underscores rather than
    spaces. (omalley)

    HADOOP-1959.  Use "/" instead of File.separator in the StatusHttpServer.
    (jimk via omalley)

    HADOOP-1626.  Improve dfsadmin help messages.
    (Lohit Vijayarenu via dhruba)

    HADOOP-1695.  The SecondaryNamenode waits for the Primary NameNode to
    start up.  (Dhruba Borthakur)

    HADOOP-1983.  Have Pipes flush the command socket when progress is sent
    to prevent timeouts during long computations. (omalley)

    HADOOP-1875.  Non-existant directories or read-only directories are
    filtered from dfs.client.buffer.dir.  (Hairong Kuang via dhruba)

    HADOOP-1992.  Fix the performance degradation in the sort validator. 
    (acmurthy via omalley)

    HADOOP-1874.  Move task-outputs' promotion/discard to a separate thread
    distinct from the main heartbeat-processing thread. The main upside being 
    that we do not lock-up the JobTracker during HDFS operations, which
    otherwise may lead to lost tasktrackers if the NameNode is unresponsive.
    (Devaraj Das via acmurthy)

    HADOOP-2026. Namenode prints out one log line for "Number of transactions"
    at most once every minute. (Dhruba Borthakur)

    HADOOP-2022.  Ensure that status information for successful tasks is correctly
    recorded at the JobTracker, so that, for example, one may view correct
    information via taskdetails.jsp. This bug was introduced by HADOOP-1874.
    (Amar Kamat via acmurthy)
                                
    HADOOP-2031.  Correctly maintain the taskid which takes the TIP to 
    completion, failing which the case of lost tasktrackers isn't handled
    properly i.e. the map TIP is incorrectly left marked as 'complete' and it
    is never rescheduled elsewhere, leading to hung reduces.
    (Devaraj Das via acmurthy)

    HADOOP-2018. The source datanode of a data transfer waits for
    a response from the target datanode before closing the data stream.
    (Hairong Kuang via dhruba)
                                
    HADOOP-2023. Disable TestLocalDirAllocator on Windows.
    (Hairong Kuang via nigel)

    HADOOP-2016.  Ignore status-updates from FAILED/KILLED tasks at the 
    TaskTracker. This fixes a race-condition which caused the tasks to wrongly 
    remain in the RUNNING state even after being killed by the JobTracker and
    thus handicap the cleanup of the task's output sub-directory. (acmurthy)

    HADOOP-1771. Fix a NullPointerException in streaming caused by an 
    IOException in MROutputThread. (lohit vijayarenu via nigel)

    HADOOP-2028. Fix distcp so that the log dir does not need to be 
    specified and the destination does not need to exist.
    (Chris Douglas via nigel)

    HADOOP-2044. The namenode protects all lease manipulations using a 
    sortedLease lock.  (Dhruba Borthakur)

    HADOOP-2051. The TaskCommit thread should not die for exceptions other
    than the InterruptedException. This behavior is there for the other long
    running threads in the JobTracker. (Arun C Murthy via ddas)

    HADOOP-1973. The FileSystem object would be accessed on the JobTracker
    through a RPC in the InterTrackerProtocol. The check for the object being
    null was missing and hence NPE would be thrown sometimes. This issue fixes
    that problem.  (Amareshwari Sri Ramadasu via ddas) 

    HADOOP-2033.  The SequenceFile.Writer.sync method was a no-op, which caused
    very uneven splits for applications like distcp that count on them.
    (omalley)

    HADOOP-2070.  Added a flush method to pipes' DownwardProtocol and call
    that before waiting for the application to finish to ensure all buffered
    data is flushed. (Owen O'Malley via acmurthy)

    HADOOP-2080.  Fixed calculation of the checksum file size when the values
    are large. (omalley)

    HADOOP-2048.  Change error handling in distcp so that each map copies
    as much as possible before reporting the error. Also report progress on
    every copy. (Chris Douglas via omalley)

    HADOOP-2073.  Change size of VERSION file after writing contents to it.
    (Konstantin Shvachko via dhruba)
 
    HADOOP-2102.  Fix the deprecated ToolBase to pass its Configuration object
    to the superceding ToolRunner to ensure it picks up the appropriate
    configuration resources. (Dennis Kubes and Enis Soztutar via acmurthy) 
 
    HADOOP-2103.  Fix minor javadoc bugs introduce by HADOOP-2046. (Nigel
    Daley via acmurthy) 

  IMPROVEMENTS

    HADOOP-1908. Restructure data node code so that block sending and 
    receiving are seperated from data transfer header handling.
    (Hairong Kuang via dhruba)

    HADOOP-1921. Save the configuration of completed/failed jobs and make them
    available via the web-ui. (Amar Kamat via devaraj)

    HADOOP-1266. Remove dependency of package org.apache.hadoop.net on 
    org.apache.hadoop.dfs.  (Hairong Kuang via dhruba)

    HADOOP-1779. Replace INodeDirectory.getINode() by a getExistingPathINodes()
    to allow the retrieval of all existing INodes along a given path in a
    single lookup. This facilitates removal of the 'parent' field in the
    inode. (Christophe Taton via dhruba)

    HADOOP-1756. Add toString() to some Writable-s. (ab)

    HADOOP-1727.  New classes: MapWritable and SortedMapWritable.
    (Jim Kellerman via ab)

    HADOOP-1651.  Improve progress reporting.
    (Devaraj Das via tomwhite)

    HADOOP-1595.  dfsshell can wait for a file to achieve its intended
    replication target. (Tsz Wo (Nicholas), SZE via dhruba)

    HADOOP-1693.  Remove un-needed log fields in DFS replication classes,
    since the log may be accessed statically. (Konstantin Shvachko via cutting)

    HADOOP-1231.  Add generics to Mapper and Reducer interfaces.
    (tomwhite via cutting)

    HADOOP-1436.  Improved command-line APIs, so that all tools need
    not subclass ToolBase, and generic parameter parser is public.
    (Enis Soztutar via cutting)

    HADOOP-1703.  DFS-internal code cleanups, removing several uses of
    the obsolete UTF8.  (Christophe Taton via cutting)

    HADOOP-1731.  Add Hadoop's version to contrib jar file names.
    (cutting)

    HADOOP-1689.  Make shell scripts more portable.  All shell scripts
    now explicitly depend on bash, but do not require that bash be
    installed in a particular location, as long as it is on $PATH.
    (cutting)

    HADOOP-1744.  Remove many uses of the deprecated UTF8 class from
    the HDFS namenode.  (Christophe Taton via cutting)

    HADOOP-1654.  Add IOUtils class, containing generic io-related
    utility methods.   (Enis Soztutar via cutting)

    HADOOP-1158.  Change JobTracker to record map-output transmission
    errors and use them to trigger speculative re-execution of tasks.
    (Arun C Murthy via cutting)

    HADOOP-1601.  Change GenericWritable to use ReflectionUtils for
    instance creation, avoiding classloader issues, and to implement
    Configurable.  (Enis Soztutar via cutting)

    HADOOP-1750.  Log standard output and standard error when forking
    task processes.  (omalley via cutting)

    HADOOP-1803.  Generalize build.xml to make files in all
    src/contrib/*/bin directories executable.  (stack via cutting)

    HADOOP-1739.  Let OS always choose the tasktracker's umbilical
    port.  Also switch default address for umbilical connections to
    loopback.  (cutting)

    HADOOP-1812. Let OS choose ports for IPC and RPC unit tests. (cutting)

    HADOOP-1825.  Create $HADOOP_PID_DIR when it does not exist.
    (Michael Bieniosek via cutting)

    HADOOP-1425.  Replace uses of ToolBase with the Tool interface.
    (Enis Soztutar via cutting)

    HADOOP-1569.  Reimplement DistCP to use the standard FileSystem/URI
    code in Hadoop so that you can copy from and to all of the supported file 
    systems.(Chris Douglas via omalley)

    HADOOP-1018.  Improve documentation w.r.t handling of lost hearbeats between 
    TaskTrackers and JobTracker. (acmurthy)

    HADOOP-1718.  Add ant targets for measuring code coverage with clover.
    (simonwillnauer via nigel)

    HADOOP-1592.  Log error messages to the client console when tasks
    fail.  (Amar Kamat via cutting)

    HADOOP-1879.  Remove some unneeded casts.  (Nilay Vaish via cutting)

    HADOOP-1878.  Add space between priority links on job details
    page. (Thomas Friol via cutting)

    HADOOP-120.  In ArrayWritable, prevent creation with null value
    class, and improve documentation.  (Cameron Pope via cutting)

    HADOOP-1926. Add a random text writer example/benchmark so that we can
    benchmark compression codecs on random data. (acmurthy via omalley)

    HADOOP-1906. Warn the user if they have an obsolete madred-default.xml
    file in their configuration directory. (acmurthy via omalley)

    HADOOP-1971.  Warn when job does not specify a jar. (enis via cutting)

    HADOOP-1942. Increase the concurrency of transaction logging to 
    edits log. Reduce the number of syncs by double-buffering the changes
    to the transaction log. (Dhruba Borthakur)

    HADOOP-2046.  Improve mapred javadoc.  (Arun C. Murthy via cutting)

    HADOOP-2105.  Improve overview.html to clarify supported platforms, 
    software pre-requisites for hadoop, how to install them on various 
    platforms and a better general description of hadoop and it's utility. 
    (Jim Kellerman via acmurthy) 


Release 0.14.4 - 2007-11-26

  BUG FIXES

    HADOOP-2140.  Add missing Apache Licensing text at the front of several
    C and C++ files.

    HADOOP-2169.  Fix the DT_SONAME field of libhdfs.so to set it to the
    correct value of 'libhdfs.so', currently it is set to the absolute path of
    libhdfs.so. (acmurthy) 

    HADOOP-2001.  Make the job priority updates and job kills synchronized on
    the JobTracker. Deadlock was seen in the JobTracker because of the lack of
    this synchronization.  (Arun C Murthy via ddas)


Release 0.14.3 - 2007-10-19

  BUG FIXES

    HADOOP-2053. Fixed a dangling reference to a memory buffer in the map 
    output sorter. (acmurthy via omalley)

    HADOOP-2036. Fix a NullPointerException in JvmMetrics class. (nigel)

    HADOOP-2043. Release 0.14.2 was compiled with Java 1.6 rather than
    Java 1.5.  (cutting)


Release 0.14.2 - 2007-10-09

  BUG FIXES

    HADOOP-1948. Removed spurious error message during block crc upgrade.
    (Raghu Angadi via dhruba)

    HADOOP-1862.  reduces are getting stuck trying to find map outputs. 
    (Arun C. Murthy via ddas)
 
    HADOOP-1977. Fixed handling of ToolBase cli options in JobClient.
    (enis via omalley)

    HADOOP-1972.  Fix LzoCompressor to ensure the user has actually asked
    to finish compression. (arun via omalley)

    HADOOP-1970.  Fix deadlock in progress reporting in the task. (Vivek
    Ratan via omalley)

    HADOOP-1978.  Name-node removes edits.new after a successful startup.
    (Konstantin Shvachko via dhruba)

    HADOOP-1955.  The Namenode tries to not pick the same source Datanode for
    a replication request if the earlier replication request for the same
    block and that source Datanode had failed.
    (Raghu Angadi via dhruba)

    HADOOP-1961.  The -get option to dfs-shell works when a single filename
    is specified.  (Raghu Angadi via dhruba)

    HADOOP-1997.  TestCheckpoint closes the edits file after writing to it,
    otherwise the rename of this file on Windows fails.
    (Konstantin Shvachko via dhruba)

Release 0.14.1 - 2007-09-04

  BUG FIXES

    HADOOP-1740.  Fix null pointer exception in sorting map outputs. (Devaraj
    Das via omalley)

    HADOOP-1790.  Fix tasktracker to work correctly on multi-homed
    boxes.  (Torsten Curdt via cutting)

    HADOOP-1798.  Fix jobtracker to correctly account for failed
    tasks.  (omalley via cutting)


Release 0.14.0 - 2007-08-17

  INCOMPATIBLE CHANGES

  1. HADOOP-1134.
     CONFIG/API - dfs.block.size must now be a multiple of
       io.byte.per.checksum, otherwise new files can not be written.
     LAYOUT - DFS layout version changed from -6 to -7, which will require an
       upgrade from previous versions.
     PROTOCOL - Datanode RPC protocol version changed from 7 to 8.

  2. HADOOP-1283
     API - deprecated file locking API.

  3. HADOOP-894
     PROTOCOL - changed ClientProtocol to fetch parts of block locations.

  4. HADOOP-1336
     CONFIG - Enable speculative execution by default.

  5. HADOOP-1197
     API - deprecated method for Configuration.getObject, because
       Configurations should only contain strings.

  6. HADOOP-1343
     API - deprecate Configuration.set(String,Object) so that only strings are
       put in Configrations.

  7. HADOOP-1207
     CLI - Fix FsShell 'rm' command to continue when a non-existent file is
       encountered.

  8. HADOOP-1473
     CLI/API - Job, TIP, and Task id formats have changed and are now unique
       across job tracker restarts.

  9. HADOOP-1400
     API - JobClient constructor now takes a JobConf object instead of a
       Configuration object.

  NEW FEATURES and BUG FIXES

  1. HADOOP-1197.  In Configuration, deprecate getObject() and add
     getRaw(), which skips variable expansion. (omalley via cutting)

  2. HADOOP-1343.  In Configuration, deprecate set(String,Object) and
     implement Iterable. (omalley via cutting)

  3. HADOOP-1344.  Add RunningJob#getJobName(). (Michael Bieniosek via cutting)

  4. HADOOP-1342.  In aggregators, permit one to limit the number of
     unique values per key.  (Runping Qi via cutting)

  5. HADOOP-1340.  Set the replication factor of the MD5 file in the filecache
     to be the same as the replication factor of the original file.
     (Dhruba Borthakur via tomwhite.)

  6. HADOOP-1355.  Fix null pointer dereference in 
     TaskLogAppender.append(LoggingEvent).  (Arun C Murthy via tomwhite.)

  7. HADOOP-1357.  Fix CopyFiles to correctly avoid removing "/".
     (Arun C Murthy via cutting)

  8. HADOOP-234.  Add pipes facility, which permits writing MapReduce
     programs in C++.

  9. HADOOP-1359.  Fix a potential NullPointerException in HDFS.
     (Hairong Kuang via cutting)

 10. HADOOP-1364.  Fix inconsistent synchronization in SequenceFile.
     (omalley via cutting)

 11. HADOOP-1379.  Add findbugs target to build.xml.
     (Nigel Daley via cutting)

 12. HADOOP-1364.  Fix various inconsistent synchronization issues.
     (Devaraj Das via cutting)

 13. HADOOP-1393.  Remove a potential unexpected negative number from
     uses of random number generator. (omalley via cutting)

 14. HADOOP-1387.  A number of "performance" code-cleanups suggested
     by findbugs.  (Arun C Murthy via cutting)

 15. HADOOP-1401.  Add contrib/hbase javadoc to tree.  (stack via cutting)

 16. HADOOP-894.  Change HDFS so that the client only retrieves a limited
     number of block locations per request from the namenode.
     (Konstantin Shvachko via cutting)

 17. HADOOP-1406.  Plug a leak in MapReduce's use of metrics.
     (David Bowen via cutting)

 18. HADOOP-1394.  Implement "performance" code-cleanups in HDFS
     suggested by findbugs.  (Raghu Angadi via cutting)

 19. HADOOP-1413.  Add example program that uses Knuth's dancing links
     algorithm to solve pentomino problems.  (omalley via cutting)

 20. HADOOP-1226.  Change HDFS so that paths it returns are always
     fully qualified.  (Dhruba Borthakur via cutting)

 21. HADOOP-800.  Improvements to HDFS web-based file browser.
     (Enis Soztutar via cutting)

 22. HADOOP-1408.  Fix a compiler warning by adding a class to replace
     a generic.  (omalley via cutting)

 23. HADOOP-1376.  Modify RandomWriter example so that it can generate
     data for the Terasort benchmark.  (Devaraj Das via cutting)

 24. HADOOP-1429.  Stop logging exceptions during normal IPC server
     shutdown.  (stack via cutting)

 25. HADOOP-1461.  Fix the synchronization of the task tracker to
     avoid lockups in job cleanup.  (Arun C Murthy via omalley)

 26. HADOOP-1446.  Update the TaskTracker metrics while the task is
     running. (Devaraj via omalley)

 27. HADOOP-1414.  Fix a number of issues identified by FindBugs as
     "Bad Practice".  (Dhruba Borthakur via cutting)

 28. HADOOP-1392.  Fix "correctness" bugs identified by FindBugs in
     fs and dfs packages.  (Raghu Angadi via cutting)

 29. HADOOP-1412.  Fix "dodgy" bugs identified by FindBugs in fs and
     io packages.  (Hairong Kuang via cutting)

 30. HADOOP-1261.  Remove redundant events from HDFS namenode's edit
     log when a datanode restarts.  (Raghu Angadi via cutting)

 31. HADOOP-1336.  Re-enable speculative execution by
     default. (omalley via cutting)

 32. HADOOP-1311.  Fix a bug in BytesWritable#set() where start offset
     was ignored.  (Dhruba Borthakur via cutting)

 33. HADOOP-1450.  Move checksumming closer to user code, so that
     checksums are created before data is stored in large buffers and
     verified after data is read from large buffers, to better catch
     memory errors.  (cutting)

 34. HADOOP-1447.  Add support in contrib/data_join for text inputs.
     (Senthil Subramanian via cutting)

 35. HADOOP-1456.  Fix TestDecommission assertion failure by setting
     the namenode to ignore the load on datanodes while allocating
     replicas.  (Dhruba Borthakur via tomwhite)

 36. HADOOP-1396.  Fix FileNotFoundException on DFS block.
     (Dhruba Borthakur via tomwhite)

 37. HADOOP-1467.  Remove redundant counters from WordCount example.
     (Owen O'Malley via tomwhite)

 38. HADOOP-1139.  Log HDFS block transitions at INFO level, to better
     enable diagnosis of problems.  (Dhruba Borthakur via cutting)

 39. HADOOP-1269.  Finer grained locking in HDFS namenode.
     (Dhruba Borthakur via cutting)

 40. HADOOP-1438.  Improve HDFS documentation, correcting typos and
     making images appear in PDF.  Also update copyright date for all
     docs.  (Luke Nezda via cutting)

 41. HADOOP-1457.  Add counters for monitoring task assignments.
     (Arun C Murthy via tomwhite)

 42. HADOOP-1472.  Fix so that timed-out tasks are counted as failures
     rather than as killed.  (Arun C Murthy via cutting)

 43. HADOOP-1234.  Fix a race condition in file cache that caused
     tasktracker to not be able to find cached files.
     (Arun C Murthy via cutting)

 44. HADOOP-1482.  Fix secondary namenode to roll info port.
     (Dhruba Borthakur via cutting)

 45. HADOOP-1300.  Improve removal of excess block replicas to be
     rack-aware.  Attempts are now made to keep replicas on more
     racks.  (Hairong Kuang via cutting)

 46. HADOOP-1417.  Disable a few FindBugs checks that generate a lot
     of spurious warnings.  (Nigel Daley via cutting)

 47. HADOOP-1320.  Rewrite RandomWriter example to bypass reduce.
     (Arun C Murthy via cutting)

 48. HADOOP-1449.  Add some examples to contrib/data_join.
     (Senthil Subramanian via cutting)

 49. HADOOP-1459.  Fix so that, in HDFS, getFileCacheHints() returns
     hostnames instead of IP addresses.  (Dhruba Borthakur via cutting)

 50. HADOOP-1493.  Permit specification of "java.library.path" system
     property in "mapred.child.java.opts" configuration property.
     (Enis Soztutar via cutting)

 51. HADOOP-1372.  Use LocalDirAllocator for HDFS temporary block
     files, so that disk space, writability, etc. is considered.
     (Dhruba Borthakur via cutting)

 52. HADOOP-1193.  Pool allocation of compression codecs.  This
     eliminates a memory leak that could cause OutOfMemoryException,
     and also substantially improves performance.
     (Arun C Murthy via cutting)

 53. HADOOP-1492.  Fix a NullPointerException handling version
     mismatch during datanode registration.
     (Konstantin Shvachko via cutting)

 54. HADOOP-1442.  Fix handling of zero-length input splits.
     (Senthil Subramanian via cutting)

 55. HADOOP-1444.  Fix HDFS block id generation to check pending
     blocks for duplicates. (Dhruba Borthakur via cutting)

 56. HADOOP-1207.  Fix FsShell's 'rm' command to not stop when one of
     the named files does not exist.  (Tsz Wo Sze via cutting)

 57. HADOOP-1475.  Clear tasktracker's file cache before it
     re-initializes, to avoid confusion.  (omalley via cutting)

 58. HADOOP-1505.  Remove spurious stacktrace in ZlibFactory
     introduced in HADOOP-1093.  (Michael Stack via tomwhite)

 59. HADOOP-1484.  Permit one to kill jobs from the web ui.  Note that
     this is disabled by default.  One must set
     "webinterface.private.actions" to enable this.
     (Enis Soztutar via cutting)

 60. HADOOP-1003.  Remove flushing of namenode edit log from primary
     namenode lock, increasing namenode throughput.
     (Dhruba Borthakur via cutting)

 61. HADOOP-1023.  Add links to searchable mail archives.
     (tomwhite via cutting)

 62. HADOOP-1504.  Fix terminate-hadoop-cluster script in contrib/ec2
     to only terminate Hadoop instances, and not other instances
     started by the same user.  (tomwhite via cutting)

 63. HADOOP-1462.  Improve task progress reporting.  Progress reports
     are no longer blocking since i/o is performed in a separate
     thread.  Reporting during sorting and more is also more
     consistent.  (Vivek Ratan via cutting)

 64. [ intentionally blank ]

 65. HADOOP-1453.  Remove some unneeded calls to FileSystem#exists()
     when opening files, reducing the namenode load somewhat.
     (Raghu Angadi via cutting)

 66. HADOOP-1489.  Fix text input truncation bug due to mark/reset.
     Add a unittest. (Bwolen Yang via cutting)

 67. HADOOP-1455.  Permit specification of arbitrary job options on
     pipes command line.  (Devaraj Das via cutting)

 68. HADOOP-1501.  Better randomize sending of block reports to
     namenode, so reduce load spikes.  (Dhruba Borthakur via cutting)

 69. HADOOP-1147.  Remove @author tags from Java source files.

 70. HADOOP-1283.  Convert most uses of UTF8 in the namenode to be
     String.  (Konstantin Shvachko via cutting)

 71. HADOOP-1511.  Speedup hbase unit tests.  (stack via cutting)

 72. HADOOP-1517.  Remove some synchronization in namenode to permit
     finer grained locking previously added.  (Konstantin Shvachko via cutting)

 73. HADOOP-1512.  Fix failing TestTextInputFormat on Windows.
     (Senthil Subramanian via nigel)

 74. HADOOP-1518.  Add a session id to job metrics, for use by HOD.
     (David Bowen via cutting)

 75. HADOOP-1292.  Change 'bin/hadoop fs -get' to first copy files to
     a temporary name, then rename them to their final name, so that
     failures don't leave partial files.  (Tsz Wo Sze via cutting)

 76. HADOOP-1377.  Add support for modification time to FileSystem and
     implement in HDFS and local implementations.  Also, alter access
     to file properties to be through a new FileStatus interface.
     (Dhruba Borthakur via cutting)

 77. HADOOP-1515.  Add MultiFileInputFormat, which can pack multiple,
     typically small, input files into each split.  (Enis Soztutar via cutting)

 78. HADOOP-1514.  Make reducers report progress while waiting for map
     outputs, so they're not killed.  (Vivek Ratan via cutting)

 79. HADOOP-1508.  Add an Ant task for FsShell operations.  Also add
     new FsShell commands "touchz", "test" and "stat".
     (Chris Douglas via cutting)

 80. HADOOP-1028.  Add log messages for server startup and shutdown.
     (Tsz Wo Sze via cutting)

 81. HADOOP-1485.  Add metrics for monitoring shuffle.
     (Devaraj Das via cutting)

 82. HADOOP-1536.  Remove file locks from libhdfs tests.
     (Dhruba Borthakur via nigel)

 83. HADOOP-1520.  Add appropriate synchronization to FSEditsLog.
     (Dhruba Borthakur via nigel)

 84. HADOOP-1513.  Fix a race condition in directory creation. 
     (Devaraj via omalley)

 85. HADOOP-1546.  Remove spurious column from HDFS web UI.
     (Dhruba Borthakur via cutting)

 86. HADOOP-1556.  Make LocalJobRunner delete working files at end of
     job run.  (Devaraj Das via tomwhite)

 87. HADOOP-1571.  Add contrib lib directories to root build.xml
     javadoc classpath.  (Michael Stack via tomwhite)

 88. HADOOP-1554.  Log killed tasks to the job history and display them on the
     web/ui. (Devaraj Das via omalley)

 89. HADOOP-1533.  Add persistent error logging for distcp. The logs are stored
    into a specified hdfs directory. (Senthil Subramanian via omalley)

 90. HADOOP-1286.  Add support to HDFS for distributed upgrades, which
     permits coordinated upgrade of datanode data.
     (Konstantin Shvachko via cutting)

 91. HADOOP-1580.  Improve contrib/streaming so that subprocess exit
     status is displayed for errors.  (John Heidemann via cutting)

 92. HADOOP-1448.  In HDFS, randomize lists of non-local block
     locations returned to client, so that load is better balanced.
     (Hairong Kuang via cutting)

 93. HADOOP-1578.  Fix datanode to send its storage id to namenode
     during registration.  (Konstantin Shvachko via cutting)

 94. HADOOP-1584.  Fix a bug in GenericWritable which limited it to
     128 types instead of 256.  (Espen Amble Kolstad via cutting)

 95. HADOOP-1473.  Make job ids unique across jobtracker restarts.
     (omalley via cutting)

 96. HADOOP-1582.  Fix hdfslib to return 0 instead of -1 at
     end-of-file, per C conventions.  (Christian Kunz via cutting)

 97. HADOOP-911.  Fix a multithreading bug in libhdfs.
     (Christian Kunz)

 98. HADOOP-1486.  Fix so that fatal exceptions in namenode cause it
     to exit.  (Dhruba Borthakur via cutting)

 99. HADOOP-1470.  Factor checksum generation and validation out of
     ChecksumFileSystem so that it can be reused by FileSystem's with
     built-in checksumming.  (Hairong Kuang via cutting)

100. HADOOP-1590.  Use relative urls in jobtracker jsp pages, so that
     webapp can be used in non-root contexts.  (Thomas Friol via cutting)

101. HADOOP-1596.  Fix the parsing of taskids by streaming and improve the
     error reporting. (omalley)

102. HADOOP-1535.  Fix the user-controlled grouping to the reduce function.
     (Vivek Ratan via omalley)

103. HADOOP-1585.  Modify GenericWritable to declare the classes as subtypes
     of Writable (Espen Amble Kolstad via omalley)

104. HADOOP-1576.  Fix errors in count of completed tasks when
     speculative execution is enabled.  (Arun C Murthy via cutting)

105. HADOOP-1598.  Fix license headers: adding missing; updating old.
     (Enis Soztutar via cutting)

106. HADOOP-1547.  Provide examples for aggregate library.
     (Runping Qi via tomwhite)

107. HADOOP-1570.  Permit jobs to enable and disable the use of
     hadoop's native library.  (Arun C Murthy via cutting)

108. HADOOP-1433.  Add job priority.  (Johan Oskarsson via tomwhite)

109. HADOOP-1597.  Add status reports and post-upgrade options to HDFS
     distributed upgrade.  (Konstantin Shvachko via cutting)

110. HADOOP-1524.  Permit user task logs to appear as they're
     created.  (Michael Bieniosek via cutting)

111. HADOOP-1599.  Fix distcp bug on Windows.  (Senthil Subramanian via cutting)

112. HADOOP-1562.  Add JVM metrics, including GC and logging stats.
     (David Bowen via cutting)

113. HADOOP-1613.  Fix "DFS Health" page to display correct time of
     last contact.  (Dhruba Borthakur via cutting)

114. HADOOP-1134.  Add optimized checksum support to HDFS.  Checksums
     are now stored with each block, rather than as parallel files.
     This reduces the namenode's memory requirements and increases
     data integrity.  (Raghu Angadi via cutting)

115. HADOOP-1400.  Make JobClient retry requests, so that clients can
     survive jobtracker problems.  (omalley via cutting)

116. HADOOP-1564.  Add unit tests for HDFS block-level checksums.
     (Dhruba Borthakur via cutting)

117. HADOOP-1620.  Reduce the number of abstract FileSystem methods,
     simplifying implementations.  (cutting)

118. HADOOP-1625.  Fix a "could not move files" exception in datanode.
     (Raghu Angadi via cutting)

119. HADOOP-1624.  Fix an infinite loop in datanode. (Raghu Angadi via cutting)

120. HADOOP-1084.  Switch mapred file cache to use file modification
     time instead of checksum to detect file changes, as checksums are
     no longer easily accessed.  (Arun C Murthy via cutting)

130. HADOOP-1623.  Fix an infinite loop when copying directories.
     (Dhruba Borthakur via cutting)

131. HADOOP-1603.  Fix a bug in namenode initialization where
     default replication is sometimes reset to one on restart.
     (Raghu Angadi via cutting)

132. HADOOP-1635.  Remove hardcoded keypair name and fix launch-hadoop-cluster
     to support later versions of ec2-api-tools.  (Stu Hood via tomwhite)

133. HADOOP-1638.  Fix contrib EC2 scripts to support NAT addressing.
     (Stu Hood via tomwhite) 

134. HADOOP-1632.  Fix an IllegalArgumentException in fsck.
     (Hairong Kuang via cutting)

135. HADOOP-1619.  Fix FSInputChecker to not attempt to read past EOF.
     (Hairong Kuang via cutting)

136. HADOOP-1640.  Fix TestDecommission on Windows.
     (Dhruba Borthakur via cutting)

137. HADOOP-1587.  Fix TestSymLink to get required system properties.
     (Devaraj Das via omalley)

138. HADOOP-1628.  Add block CRC protocol unit tests. (Raghu Angadi via omalley)

139. HADOOP-1653.  FSDirectory code-cleanups. FSDirectory.INode
     becomes a static class.  (Christophe Taton via dhruba)

140. HADOOP-1066.  Restructure documentation to make more user
     friendly.  (Connie Kleinjans and Jeff Hammerbacher via cutting)

141. HADOOP-1551.  libhdfs supports setting replication factor and
     retrieving modification time of files.  (Sameer Paranjpye via dhruba)

141. HADOOP-1647.  FileSystem.getFileStatus returns valid values for "/".
     (Dhruba Borthakur via dhruba)

142. HADOOP-1657.  Fix NNBench to ensure that the block size is a
     multiple of bytes.per.checksum. (Raghu Angadi via dhruba)

143. HADOOP-1553.  Replace user task output and log capture code to use shell
     redirection instead of copier threads in the TaskTracker. Capping the
     size of the output is now done via tail in memory and thus should not be 
     large. The output of the tasklog servlet is not forced into UTF8 and is
     not buffered entirely in memory. (omalley)
     Configuration changes to hadoop-default.xml:
       remove mapred.userlog.num.splits
       remove mapred.userlog.purge.splits
       change default mapred.userlog.limit.kb to 0 (no limit)
       change default mapred.userlog.retain.hours to 24
     Configuration changes to log4j.properties:
       remove log4j.appender.TLA.noKeepSplits
       remove log4j.appender.TLA.purgeLogSplits
       remove log4j.appender.TLA.logsRetainHours
     URL changes:
       http://<tasktracker>/tasklog.jsp -> http://<tasktracker>tasklog with
         parameters limited to start and end, which may be positive (from
         start) or negative (from end).
     Environment:
       require bash (v2 or later) and tail

144. HADOOP-1659.  Fix a job id/job name mixup. (Arun C. Murthy via omalley)

145. HADOOP-1665.  With HDFS Trash enabled and the same file was created
     and deleted more than once, the suceeding deletions creates Trash item
     names suffixed with a integer.  (Dhruba Borthakur via dhruba)

146. HADOOP-1666.  FsShell object can be used for multiple fs commands.
     (Dhruba Borthakur via dhruba)

147. HADOOP-1654.  Remove performance regression introduced by Block CRC.
     (Raghu Angadi via dhruba)

148. HADOOP-1680.  Improvements to Block CRC upgrade messages.
     (Raghu Angadi via dhruba)

149. HADOOP-71.  Allow Text and SequenceFile Map/Reduce inputs from non-default 
     filesystems. (omalley)

150. HADOOP-1568.  Expose HDFS as xml/http filesystem to provide cross-version
     compatability. (Chris Douglas via omalley)

151. HADOOP-1668.  Added an INCOMPATIBILITY section to CHANGES.txt. (nigel)

152. HADOOP-1629.  Added a upgrade test for HADOOP-1134.
     (Raghu Angadi via nigel)

153. HADOOP-1698.  Fix performance problems on map output sorting for jobs
     with large numbers of reduces. (Devaraj Das via omalley)

154. HADOOP-1716.  Fix a Pipes wordcount example to remove the 'file:'
     schema from its output path.  (omalley via cutting)

155. HADOOP-1714.  Fix TestDFSUpgradeFromImage to work on Windows.
     (Raghu Angadi via nigel)

156. HADOOP-1663.  Return a non-zero exit code if streaming fails. (Lohit Renu
     via omalley)

157. HADOOP-1712.  Fix an unhandled exception on datanode during block
     CRC upgrade. (Raghu Angadi via cutting)

158. HADOOP-1717.  Fix TestDFSUpgradeFromImage to work on Solaris.
     (nigel via cutting)

159. HADOOP-1437.  Add Eclipse plugin in contrib.
     (Eugene Hung and Christophe Taton via cutting)


Release 0.13.0 - 2007-06-08

 1. HADOOP-1047.  Fix TestReplication to succeed more reliably.
    (Hairong Kuang via cutting)

 2. HADOOP-1063.  Fix a race condition in MiniDFSCluster test code.
    (Hairong Kuang via cutting)

 3. HADOOP-1101.  In web ui, split shuffle statistics from reduce
    statistics, and add some task averages.  (Devaraj Das via cutting)

 4. HADOOP-1071.  Improve handling of protocol version mismatch in
    JobTracker.  (Tahir Hashmi via cutting)

 5. HADOOP-1116.  Increase heap size used for contrib unit tests.
    (Philippe Gassmann via cutting)

 6. HADOOP-1120.  Add contrib/data_join, tools to simplify joining
    data from multiple sources using MapReduce.  (Runping Qi via cutting)

 7. HADOOP-1064.  Reduce log level of some DFSClient messages.
    (Dhruba Borthakur via cutting)

 8. HADOOP-1137.  Fix StatusHttpServer to work correctly when
    resources are in a jar file.  (Benjamin Reed via cutting)

 9. HADOOP-1094.  Optimize generated Writable implementations for
    records to not allocate a new BinaryOutputArchive or
    BinaryInputArchive per call.  (Milind Bhandarkar via cutting)

10. HADOOP-1068.  Improve error message for clusters with 0 datanodes.
    (Dhruba Borthakur via tomwhite)

11. HADOOP-1122.  Fix divide-by-zero exception in FSNamesystem
    chooseTarget method.  (Dhruba Borthakur via tomwhite)

12. HADOOP-1131.  Add a closeAll() static method to FileSystem.
    (Philippe Gassmann via tomwhite)

13. HADOOP-1085.  Improve port selection in HDFS and MapReduce test
    code.  Ports are now selected by the OS during testing rather than
    by probing for free ports, improving test reliability.
    (Arun C Murthy via cutting)

14. HADOOP-1153.  Fix HDFS daemons to correctly stop their threads.
    (Konstantin Shvachko via cutting)

15. HADOOP-1146.  Add a counter for reduce input keys and rename the
    "reduce input records" counter to be "reduce input groups".
    (David Bowen via cutting)

16. HADOOP-1165.  In records, replace idential generated toString
    methods with a method on the base class.  (Milind Bhandarkar via cutting)

17. HADOOP-1164.  Fix TestReplicationPolicy to specify port zero, so
    that a free port is automatically selected.  (omalley via cutting)

18. HADOOP-1166.  Add a NullOutputFormat and use it in the
    RandomWriter example.  (omalley via cutting)

19. HADOOP-1169.  Fix a cut/paste error in CopyFiles utility so that
    S3-based source files are correctly copied.  (Michael Stack via cutting)

20. HADOOP-1167.  Remove extra synchronization in InMemoryFileSystem.
    (omalley via cutting)

21. HADOOP-1110.  Fix an off-by-one error counting map inputs.
    (David Bowen via cutting)

22. HADOOP-1178.  Fix a NullPointerException during namenode startup.
    (Dhruba Borthakur via cutting)

23. HADOOP-1011.  Fix a ConcurrentModificationException when viewing
    job history.  (Tahir Hashmi via cutting)

24. HADOOP-672.  Improve help for fs shell commands.
    (Dhruba Borthakur via cutting)

25. HADOOP-1170.  Improve datanode performance by removing device
    checks from common operations.  (Igor Bolotin via cutting)

26. HADOOP-1090.  Fix SortValidator's detection of whether the input 
    file belongs to the sort-input or sort-output directory.
    (Arun C Murthy via tomwhite)

27. HADOOP-1081.  Fix bin/hadoop on Darwin.  (Michael Bieniosek via cutting)

28. HADOOP-1045.  Add contrib/hbase, a BigTable-like online database.
    (Jim Kellerman via cutting)

29. HADOOP-1156.  Fix a NullPointerException in MiniDFSCluster.
    (Hairong Kuang via cutting)

30. HADOOP-702.  Add tools to help automate HDFS upgrades.
    (Konstantin Shvachko via cutting)

31. HADOOP-1163.  Fix ganglia metrics to aggregate metrics from different
    hosts properly.  (Michael Bieniosek via tomwhite)

32. HADOOP-1194.  Make compression style record level for map output
    compression.  (Arun C Murthy via tomwhite)

33. HADOOP-1187.  Improve DFS Scalability: avoid scanning entire list of
    datanodes in getAdditionalBlocks.  (Dhruba Borthakur via tomwhite)

34. HADOOP-1133.  Add tool to analyze and debug namenode on a production
    cluster.  (Dhruba Borthakur via tomwhite)

35. HADOOP-1151.  Remove spurious printing to stderr in streaming 
    PipeMapRed.  (Koji Noguchi via tomwhite)

36. HADOOP-988.  Change namenode to use a single map of blocks to metadata.
    (Raghu Angadi via tomwhite)

37. HADOOP-1203.  Change UpgradeUtilities used by DFS tests to use
    MiniDFSCluster to start and stop NameNode/DataNodes.
    (Nigel Daley via tomwhite)

38. HADOOP-1217.  Add test.timeout property to build.xml, so that
    long-running unit tests may be automatically terminated.
    (Nigel Daley via cutting)

39. HADOOP-1149.  Improve DFS Scalability: make 
    processOverReplicatedBlock() a no-op if blocks are not 
    over-replicated.  (Raghu Angadi via tomwhite)

40. HADOOP-1149.  Improve DFS Scalability: optimize getDistance(), 
    contains(), and isOnSameRack() in NetworkTopology.  
    (Hairong Kuang via tomwhite)

41. HADOOP-1218.  Make synchronization on TaskTracker's RunningJob 
    object consistent.  (Devaraj Das via tomwhite)

42. HADOOP-1219.  Ignore progress report once a task has reported as 
    'done'.  (Devaraj Das via tomwhite)

43. HADOOP-1114.  Permit user to specify additional CLASSPATH elements
    with a HADOOP_CLASSPATH environment variable. (cutting)

44. HADOOP-1198.  Remove ipc.client.timeout parameter override from 
    unit test configuration.  Using the default is more robust and
    has almost the same run time.  (Arun C Murthy via tomwhite)

45. HADOOP-1211.  Remove deprecated constructor and unused static 
    members in DataNode class.  (Konstantin Shvachko via tomwhite)

46. HADOOP-1136.  Fix ArrayIndexOutOfBoundsException in 
    FSNamesystem$UnderReplicatedBlocks add() method.  
    (Hairong Kuang via tomwhite)

47. HADOOP-978.  Add the client name and the address of the node that
    previously started to create the file to the description of 
    AlreadyBeingCreatedException.  (Konstantin Shvachko via tomwhite)

48. HADOOP-1001.  Check the type of keys and values generated by the 
    mapper against the types specified in JobConf.  
    (Tahir Hashmi via tomwhite)

49. HADOOP-971.  Improve DFS Scalability: Improve name node performance
    by adding a hostname to datanodes map.  (Hairong Kuang via tomwhite)

50. HADOOP-1189.  Fix 'No space left on device' exceptions on datanodes.
    (Raghu Angadi via tomwhite)

51. HADOOP-819.  Change LineRecordWriter to not insert a tab between
    key and value when either is null, and to print nothing when both
    are null.  (Runping Qi via cutting)

52. HADOOP-1204.  Rename InputFormatBase to be FileInputFormat, and
    deprecate InputFormatBase.  Also make LineRecordReader easier to
    extend.  (Runping Qi via cutting)

53. HADOOP-1213.  Improve logging of errors by IPC server, to
    consistently include the service name and the call.  (cutting)

54. HADOOP-1238.  Fix metrics reporting by TaskTracker to correctly
    track maps_running and reduces_running.
    (Michael Bieniosek via cutting)

55. HADOOP-1093.  Fix a race condition in HDFS where blocks were
    sometimes erased before they were reported written.
    (Dhruba Borthakur via cutting)

56. HADOOP-1239.  Add a package name to some testjar test classes.
    (Jim Kellerman via cutting)

57. HADOOP-1241.  Fix NullPointerException in processReport when 
    namenode is restarted.  (Dhruba Borthakur via tomwhite)

58. HADOOP-1244.  Fix stop-dfs.sh to no longer incorrectly specify 
    slaves file for stopping datanode.  
    (Michael Bieniosek via tomwhite)

59. HADOOP-1253.  Fix ConcurrentModificationException and 
    NullPointerException in JobControl.  
    (Johan Oskarson via tomwhite)

60. HADOOP-1256.  Fix NameNode so that multiple DataNodeDescriptors
    can no longer be created on startup.  (Hairong Kuang via cutting)

61. HADOOP-1214.  Replace streaming classes with new counterparts 
    from Hadoop core.  (Runping Qi via tomwhite)

62. HADOOP-1250.  Move a chmod utility from streaming to FileUtil.
    (omalley via cutting)

63. HADOOP-1258.  Fix TestCheckpoint test case to wait for 
    MiniDFSCluster to be active.  (Nigel Daley via tomwhite)

64. HADOOP-1148.  Re-indent all Java source code to consistently use
    two spaces per indent level.  (cutting)

65. HADOOP-1251.  Add a method to Reporter to get the map InputSplit.
    (omalley via cutting)

66. HADOOP-1224.  Fix "Browse the filesystem" link to no longer point 
    to dead datanodes.  (Enis Soztutar via tomwhite)

67. HADOOP-1154.  Fail a streaming task if the threads reading from or 
    writing to the streaming process fail.  (Koji Noguchi via tomwhite)

68. HADOOP-968.  Move shuffle and sort to run in reduce's child JVM,
    rather than in TaskTracker.  (Devaraj Das via cutting)

69. HADOOP-1111.  Add support for client notification of job
    completion. If the job configuration has a job.end.notification.url
    property it will make a HTTP GET request to the specified URL.
    The number of retries and the interval between retries is also
    configurable. (Alejandro Abdelnur via tomwhite)

70. HADOOP-1275.  Fix misspelled job notification property in
    hadoop-default.xml.  (Alejandro Abdelnur via tomwhite)

71. HADOOP-1152.  Fix race condition in MapOutputCopier.copyOutput file
    rename causing possible reduce task hang.
    (Tahir Hashmi via tomwhite)

72. HADOOP-1050.  Distinguish between failed and killed tasks so as to 
    not count a lost tasktracker against the job.  
    (Arun C Murthy via tomwhite)

73. HADOOP-1271.  Fix StreamBaseRecordReader to be able to log record 
    data that's not UTF-8.  (Arun C Murthy via tomwhite)

74. HADOOP-1190.  Fix unchecked warnings in main Hadoop code.  
    (tomwhite)

75. HADOOP-1127.  Fix AlreadyBeingCreatedException in namenode for 
    jobs run with speculative execution.
    (Arun C Murthy via tomwhite)

76. HADOOP-1282.  Omnibus HBase patch.  Improved tests & configuration.
    (Jim Kellerman via cutting)

77. HADOOP-1262.  Make dfs client try to read from a different replica 
    of the checksum file when a checksum error is detected.  
    (Hairong Kuang via tomwhite)

78. HADOOP-1279.  Fix JobTracker to maintain list of recently
    completed jobs by order of completion, not submission.
    (Arun C Murthy via cutting)

79. HADOOP-1284.  In contrib/streaming, permit flexible specification
    of field delimiter and fields for partitioning and sorting.
    (Runping Qi via cutting)

80. HADOOP-1176.  Fix a bug where reduce would hang when a map had
    more than 2GB of output for it.  (Arun C Murthy via cutting)

81. HADOOP-1293.  Fix contrib/streaming to print more than the first
    twenty lines of standard error.  (Koji Noguchi via cutting)

82. HADOOP-1297.  Fix datanode so that requests to remove blocks that
    do not exist no longer causes block reports to be re-sent every
    second.  (Dhruba Borthakur via cutting)

83. HADOOP-1216.  Change MapReduce so that, when numReduceTasks is
    zero, map outputs are written directly as final output, skipping
    shuffle, sort and reduce.  Use this to implement reduce=NONE
    option in contrib/streaming.  (Runping Qi via cutting)

84. HADOOP-1294.  Fix unchecked warnings in main Hadoop code under 
    Java 6.  (tomwhite)

85. HADOOP-1299.  Fix so that RPC will restart after RPC.stopClient()
    has been called.  (Michael Stack via cutting)

86. HADOOP-1278.  Improve blacklisting of TaskTrackers by JobTracker,
    to reduce false positives.  (Arun C Murthy via cutting)

87. HADOOP-1290.  Move contrib/abacus into mapred/lib/aggregate.
    (Runping Qi via cutting)

88. HADOOP-1272.  Extract inner classes from FSNamesystem into separate 
    classes.  (Dhruba Borthakur via tomwhite)

89. HADOOP-1247.  Add support to contrib/streaming for aggregate
    package, formerly called Abacus.  (Runping Qi via cutting)

90. HADOOP-1061.  Fix bug in listing files in the S3 filesystem.
    NOTE: this change is not backwards compatible!  You should use the 
    MigrationTool supplied to migrate existing S3 filesystem data to 
    the new format.  Please backup your data first before upgrading 
    (using 'hadoop distcp' for example).  (tomwhite)

91. HADOOP-1304.  Make configurable the maximum number of task
    attempts before a job fails.  (Devaraj Das via cutting)

92. HADOOP-1308.  Use generics to restrict types when classes are
    passed as parameters to JobConf methods. (Michael Bieniosek via cutting)

93. HADOOP-1312.  Fix a ConcurrentModificationException in NameNode
    that killed the heartbeat monitoring thread.
    (Dhruba Borthakur via cutting)

94. HADOOP-1315.  Clean up contrib/streaming, switching it to use core
    classes more and removing unused code.  (Runping Qi via cutting)

95. HADOOP-485.  Allow a different comparator for grouping keys in
    calls to reduce.  (Tahir Hashmi via cutting)

96. HADOOP-1322.  Fix TaskTracker blacklisting to work correctly in
    one- and two-node clusters.  (Arun C Murthy via cutting)

97. HADOOP-1144.  Permit one to specify a maximum percentage of tasks
    that can fail before a job is aborted.  The default is zero.
    (Arun C Murthy via cutting)

98. HADOOP-1184.  Fix HDFS decomissioning to complete when the only
    copy of a block is on a decommissioned node. (Dhruba Borthakur via cutting)

99. HADOOP-1263.  Change DFSClient to retry certain namenode calls
    with a random, exponentially increasing backoff time, to avoid
    overloading the namenode on, e.g., job start.  (Hairong Kuang via cutting)

100. HADOOP-1325.  First complete, functioning version of HBase.
    (Jim Kellerman via cutting)

101. HADOOP-1276.  Make tasktracker expiry interval configurable.
    (Arun C Murthy via cutting)

102. HADOOP-1326.  Change JobClient#RunJob() to return the job.
    (omalley via cutting)

103. HADOOP-1270.  Randomize the fetch of map outputs, speeding the
     shuffle.  (Arun C Murthy via cutting)

104. HADOOP-1200.  Restore disk checking lost in HADOOP-1170.
     (Hairong Kuang via cutting)

105. HADOOP-1252.  Changed MapReduce's allocation of local files to
     use round-robin among available devices, rather than a hashcode.
     More care is also taken to not allocate files on full or offline
     drives.  (Devaraj Das via cutting)

106. HADOOP-1324.  Change so that an FSError kills only the task that
     generates it rather than the entire task tracker.
     (Arun C Murthy via cutting)

107. HADOOP-1310.  Fix unchecked warnings in aggregate code.  (tomwhite)

108. HADOOP-1255.  Fix a bug where the namenode falls into an infinite
     loop trying to remove a dead node.  (Hairong Kuang via cutting)

109. HADOOP-1160.  Fix DistributedFileSystem.close() to close the
     underlying FileSystem, correctly aborting files being written.
     (Hairong Kuang via cutting)

110. HADOOP-1341.  Fix intermittent failures in HBase unit tests
     caused by deadlock.  (Jim Kellerman via cutting)

111. HADOOP-1350.  Fix shuffle performance problem caused by forcing
     chunked encoding of map outputs.  (Devaraj Das via cutting)

112. HADOOP-1345.  Fix HDFS to correctly retry another replica when a
     checksum error is encountered.  (Hairong Kuang via cutting)

113. HADOOP-1205.  Improve synchronization around HDFS block map.
     (Hairong Kuang via cutting)

114. HADOOP-1353.  Fix a potential NullPointerException in namenode.
     (Dhruba Borthakur via cutting)

115. HADOOP-1354.  Fix a potential NullPointerException in FsShell.
     (Hairong Kuang via cutting)

116. HADOOP-1358.  Fix a potential bug when DFSClient calls skipBytes.
     (Hairong Kuang via cutting)

117. HADOOP-1356.  Fix a bug in ValueHistogram.  (Runping Qi via cutting)

118. HADOOP-1363.  Fix locking bug in JobClient#waitForCompletion().
     (omalley via cutting)

119. HADOOP-1368.  Fix inconsistent synchronization in JobInProgress.
     (omalley via cutting)

120. HADOOP-1369.  Fix inconsistent synchronization in TaskTracker.
     (omalley via cutting)

121. HADOOP-1361.  Fix various calls to skipBytes() to check return
     value. (Hairong Kuang via cutting)

122. HADOOP-1388.  Fix a potential NullPointerException in web ui.
     (Devaraj Das via cutting)

123. HADOOP-1385.  Fix MD5Hash#hashCode() to generally hash to more
     than 256 values.  (omalley via cutting)

124. HADOOP-1386.  Fix Path to not permit the empty string as a
     path, as this has lead to accidental file deletion.  Instead
     force applications to use "." to name the default directory.
     (Hairong Kuang via cutting)

125. HADOOP-1407.  Fix integer division bug in JobInProgress which
     meant failed tasks didn't cause the job to fail.
     (Arun C Murthy via tomwhite)

126. HADOOP-1427.  Fix a typo that caused GzipCodec to incorrectly use
     a very small input buffer.  (Espen Amble Kolstad via cutting)

127. HADOOP-1435.  Fix globbing code to no longer use the empty string
     to indicate the default directory, per HADOOP-1386.
     (Hairong Kuang via cutting)

128. HADOOP-1411.  Make task retry framework handle 
     AlreadyBeingCreatedException when wrapped as a RemoteException.
     (Hairong Kuang via tomwhite)

129. HADOOP-1242.  Improve handling of DFS upgrades.
     (Konstantin Shvachko via cutting)

130. HADOOP-1332.  Fix so that TaskTracker exits reliably during unit
     tests on Windows.  (omalley via cutting)

131. HADOOP-1431.  Fix so that sort progress reporting during map runs
     only while sorting, so that stuck maps are correctly terminated.
     (Devaraj Das and Arun C Murthy via cutting)

132. HADOOP-1452.  Change TaskTracker.MapOutputServlet.doGet.totalRead
     to a long, permitting map outputs to exceed 2^31 bytes.
     (omalley via cutting)

133. HADOOP-1443.  Fix a bug opening zero-length files in HDFS.
     (Konstantin Shvachko via cutting)


Release 0.12.3 - 2007-04-06

 1. HADOOP-1162.  Fix bug in record CSV and XML serialization of
    binary values.  (Milind Bhandarkar via cutting)

 2. HADOOP-1123.  Fix NullPointerException in LocalFileSystem when
    trying to recover from a checksum error.
    (Hairong Kuang & Nigel Daley via tomwhite)

 3. HADOOP-1177.  Fix bug where IOException in MapOutputLocation.getFile
    was not being logged.  (Devaraj Das via tomwhite)

 4. HADOOP-1175.  Fix bugs in JSP for displaying a task's log messages.
    (Arun C Murthy via cutting)

 5. HADOOP-1191.  Fix map tasks to wait until sort progress thread has
    stopped before reporting the task done.  (Devaraj Das via cutting)

 6. HADOOP-1192.  Fix an integer overflow bug in FSShell's 'dus'
    command and a performance problem in HDFS's implementation of it.
    (Hairong Kuang via cutting)

 7. HADOOP-1105. Fix reducers to make "progress" while iterating 
    through values.  (Devaraj Das & Owen O'Malley via tomwhite)

 8. HADOOP-1179. Make Task Tracker close index file as soon as the read 
    is done when serving get-map-output requests.  
    (Devaraj Das via tomwhite)


Release 0.12.2 - 2007-23-17

 1. HADOOP-1135.  Fix bug in block report processing which may cause
    the namenode to delete blocks.  (Dhruba Borthakur via tomwhite)

 2. HADOOP-1145.  Make XML serializer and deserializer classes public
    in record package.  (Milind Bhandarkar via cutting)

 3. HADOOP-1140.  Fix a deadlock in metrics. (David Bowen via cutting)

 4. HADOOP-1150.  Fix streaming -reducer and -mapper to give them
    defaults. (Owen O'Malley via tomwhite)


Release 0.12.1 - 2007-03-17

 1. HADOOP-1035.  Fix a StackOverflowError in FSDataSet.
    (Raghu Angadi via cutting)

 2. HADOOP-1053.  Fix VInt representation of negative values.  Also
    remove references in generated record code to methods outside of
    the record package and improve some record documentation.
    (Milind Bhandarkar via cutting)

 3. HADOOP-1067.  Compile fails if Checkstyle jar is present in lib
    directory. Also remove dependency on a particular Checkstyle
    version number. (tomwhite)

 4. HADOOP-1060.  Fix an IndexOutOfBoundsException in the JobTracker
    that could cause jobs to hang.  (Arun C Murthy via cutting)

 5. HADOOP-1077.  Fix a race condition fetching map outputs that could
    hang reduces.  (Devaraj Das via cutting)

 6. HADOOP-1083.  Fix so that when a cluster restarts with a missing
    datanode, its blocks are replicated.  (Hairong Kuang via cutting)

 7. HADOOP-1082.  Fix a NullPointerException in ChecksumFileSystem.
    (Hairong Kuang via cutting)

 8. HADOOP-1088.  Fix record serialization of negative values.
    (Milind Bhandarkar via cutting)

 9. HADOOP-1080.  Fix bug in bin/hadoop on Windows when native
    libraries are present.  (ab via cutting)

10. HADOOP-1091.  Fix a NullPointerException in MetricsRecord.
    (David Bowen via tomwhite)

11. HADOOP-1092.  Fix a NullPointerException in HeartbeatMonitor
    thread. (Hairong Kuang via tomwhite)

12. HADOOP-1112.  Fix a race condition in Hadoop metrics.
    (David Bowen via tomwhite)

13. HADOOP-1108.  Checksummed file system should retry reading if a
    different replica is found when handling ChecksumException.
    (Hairong Kuang via tomwhite)

14. HADOOP-1070.  Fix a problem with number of racks and datanodes
    temporarily doubling.  (Konstantin Shvachko via tomwhite)

15. HADOOP-1099.  Fix NullPointerException in JobInProgress.
    (Gautam Kowshik via tomwhite)

16. HADOOP-1115.  Fix bug where FsShell copyToLocal doesn't
    copy directories.  (Hairong Kuang via tomwhite)

17. HADOOP-1109.  Fix NullPointerException in StreamInputFormat.
    (Koji Noguchi via tomwhite)

18. HADOOP-1117.  Fix DFS scalability: when the namenode is
    restarted it consumes 80% CPU. (Dhruba Borthakur via
    tomwhite)

19. HADOOP-1089.  Make the C++ version of write and read v-int
    agree with the Java versions.  (Milind Bhandarkar via
    tomwhite)

20. HADOOP-1096.  Rename InputArchive and OutputArchive and
    make them public. (Milind Bhandarkar via tomwhite)

21. HADOOP-1128.  Fix missing progress information in map tasks.
    (Espen Amble Kolstad, Andrzej Bialecki, and Owen O'Malley
    via tomwhite)

22. HADOOP-1129.  Fix DFSClient to not hide IOExceptions in
    flush method.  (Hairong Kuang via tomwhite)

23. HADOOP-1126.  Optimize CPU usage for under replicated blocks
    when cluster restarts.  (Hairong Kuang via tomwhite)


Release 0.12.0 - 2007-03-02

 1. HADOOP-975.  Separate stdout and stderr from tasks.
    (Arun C Murthy via cutting)

 2. HADOOP-982.  Add some setters and a toString() method to
    BytesWritable.  (omalley via cutting)

 3. HADOOP-858.  Move contrib/smallJobsBenchmark to src/test, removing
    obsolete bits. (Nigel Daley via cutting)

 4. HADOOP-992.  Fix MiniMR unit tests to use MiniDFS when specified,
    rather than the local FS.  (omalley via cutting)

 5. HADOOP-954.  Change use of metrics to use callback mechanism.
    Also rename utility class Metrics to MetricsUtil.
    (David Bowen & Nigel Daley via cutting)

 6. HADOOP-893.  Improve HDFS client's handling of dead datanodes.
    The set is no longer reset with each block, but rather is now
    maintained for the life of an open file.  (Raghu Angadi via cutting)

 7. HADOOP-882.  Upgrade to jets3t version 0.5, used by the S3
    FileSystem.  This version supports retries.  (Michael Stack via cutting)

 8. HADOOP-977.  Send task's stdout and stderr to JobClient's stdout
    and stderr respectively, with each line tagged by the task's name.
    (Arun C Murthy via cutting)

 9. HADOOP-761.  Change unit tests to not use /tmp.  (Nigel Daley via cutting)

10. HADOOP-1007. Make names of metrics used in Hadoop unique.
    (Nigel Daley via cutting)

11. HADOOP-491.  Change mapred.task.timeout to be per-job, and make a
    value of zero mean no timeout.  Also change contrib/streaming to
    disable task timeouts.  (Arun C Murthy via cutting)

12. HADOOP-1010.  Add Reporter.NULL, a Reporter implementation that
    does nothing.  (Runping Qi via cutting)

13. HADOOP-923.  In HDFS NameNode, move replication computation to a
    separate thread, to improve heartbeat processing time.
    (Dhruba Borthakur via cutting) 

14. HADOOP-476.  Rewrite contrib/streaming command-line processing,
    improving parameter validation.  (Sanjay Dahiya via cutting)

15. HADOOP-973.  Improve error messages in Namenode.  This should help
    to track down a problem that was appearing as a
    NullPointerException.  (Dhruba Borthakur via cutting) 

16. HADOOP-649.  Fix so that jobs with no tasks are not lost.
    (Thomas Friol via cutting)

17. HADOOP-803.  Reduce memory use by HDFS namenode, phase I.
    (Raghu Angadi via cutting)

18. HADOOP-1021.  Fix MRCaching-based unit tests on Windows.
    (Nigel Daley via cutting)

19. HADOOP-889.  Remove duplicate code from HDFS unit tests.
    (Milind Bhandarkar via cutting)

20. HADOOP-943.  Improve HDFS's fsck command to display the filename
    for under-replicated blocks.  (Dhruba Borthakur via cutting) 

21. HADOOP-333.  Add validator for sort benchmark output.
    (Arun C Murthy via cutting)

22. HADOOP-947.  Improve performance of datanode decomissioning.
    (Dhruba Borthakur via cutting)

23. HADOOP-442.  Permit one to specify hosts allowed to connect to
    namenode and jobtracker with include and exclude files.  (Wendy
    Chien via cutting)

24. HADOOP-1017.  Cache constructors, for improved performance.
    (Ron Bodkin via cutting)

25. HADOOP-867.  Move split creation out of JobTracker to client.
    Splits are now saved in a separate file, read by task processes
    directly, so that user code is no longer required in the
    JobTracker.  (omalley via cutting)

26. HADOOP-1006.  Remove obsolete '-local' option from test code.
    (Gautam Kowshik via cutting)

27. HADOOP-952. Create a public (shared) Hadoop EC2 AMI.
    The EC2 scripts now support launch of public AMIs.
    (tomwhite)
    
28. HADOOP-1025. Remove some obsolete code in ipc.Server.  (cutting)

29. HADOOP-997. Implement S3 retry mechanism for failed block
    transfers. This includes a generic retry mechanism for use
    elsewhere in Hadoop. (tomwhite)

30. HADOOP-990.  Improve HDFS support for full datanode volumes.
    (Raghu Angadi via cutting)

31. HADOOP-564.  Replace uses of "dfs://" URIs with the more standard
    "hdfs://".  (Wendy Chien via cutting)

32. HADOOP-1030.  In unit tests, unify setting of ipc.client.timeout.
    Also increase the value used from one to two seconds, in hopes of
    making tests complete more reliably.  (cutting)

33. HADOOP-654.  Stop assigning tasks to a tasktracker if it has
    failed more than a specified number in the job.
    (Arun C Murthy via cutting)

34. HADOOP-985.  Change HDFS to identify nodes by IP address rather
    than by DNS hostname.  (Raghu Angadi via cutting)

35. HADOOP-248.  Optimize location of map outputs to not use random
    probes.  (Devaraj Das via cutting)

36. HADOOP-1029.  Fix streaming's input format to correctly seek to
    the start of splits.  (Arun C Murthy via cutting)

37. HADOOP-492.  Add per-job and per-task counters.  These are
    incremented via the Reporter interface and available through the
    web ui and the JobClient API.  The mapreduce framework maintains a
    few basic counters, and applications may add their own.  Counters
    are also passed to the metrics system.
    (David Bowen via cutting)

38. HADOOP-1034.  Fix datanode to better log exceptions.
    (Philippe Gassmann via cutting)

39. HADOOP-878.  In contrib/streaming, fix reducer=NONE to work with
    multiple maps.  (Arun C Murthy via cutting)

40. HADOOP-1039.  In HDFS's TestCheckpoint, avoid restarting
    MiniDFSCluster so often, speeding this test.  (Dhruba Borthakur via cutting)

41. HADOOP-1040.  Update RandomWriter example to use counters and
    user-defined input and output formats.  (omalley via cutting)

42. HADOOP-1027.  Fix problems with in-memory merging during shuffle
    and re-enable this optimization.  (Devaraj Das via cutting)

43. HADOOP-1036.  Fix exception handling in TaskTracker to keep tasks
    from being lost.  (Arun C Murthy via cutting)

44. HADOOP-1042.  Improve the handling of failed map output fetches.
    (Devaraj Das via cutting)

45. HADOOP-928.  Make checksums optional per FileSystem.
    (Hairong Kuang via cutting)

46. HADOOP-1044.  Fix HDFS's TestDecommission to not spuriously fail.
    (Wendy Chien via cutting)

47. HADOOP-972.  Optimize HDFS's rack-aware block placement algorithm.
    (Hairong Kuang via cutting)

48. HADOOP-1043.  Optimize shuffle, increasing parallelism.
    (Devaraj Das via cutting)

49. HADOOP-940.  Improve HDFS's replication scheduling.
    (Dhruba Borthakur via cutting) 

50. HADOOP-1020.  Fix a bug in Path resolution, and a with unit tests
    on Windows.  (cutting)

51. HADOOP-941.  Enhance record facility.
    (Milind Bhandarkar via cutting)

52. HADOOP-1000.  Fix so that log messages in task subprocesses are
    not written to a task's standard error.  (Arun C Murthy via cutting)

53. HADOOP-1037.  Fix bin/slaves.sh, which currently only works with
    /bin/bash, to specify /bin/bash rather than /bin/sh.  (cutting)

54. HADOOP-1046. Clean up tmp from partially received stale block files. (ab)

55. HADOOP-1041.  Optimize mapred counter implementation.  Also group
    counters by their declaring Enum.  (David Bowen via cutting)

56. HADOOP-1032.  Permit one to specify jars that will be cached
    across multiple jobs.  (Gautam Kowshik via cutting)

57. HADOOP-1051.  Add optional checkstyle task to build.xml.  To use
    this developers must download the (LGPL'd) checkstyle jar
    themselves.  (tomwhite via cutting)

58. HADOOP-1049.  Fix a race condition in IPC client.
    (Devaraj Das via cutting)

60. HADOOP-1056.  Check HDFS include/exclude node lists with both IP
    address and hostname.  (Wendy Chien via cutting)

61. HADOOP-994.  In HDFS, limit the number of blocks invalidated at
    once.  Large lists were causing datenodes to timeout.
    (Dhruba Borthakur via cutting) 

62. HADOOP-432.  Add a trash feature, disabled by default.  When
    enabled, the FSShell 'rm' command will move things to a trash
    directory in the filesystem.  In HDFS, a thread periodically
    checkpoints the trash and removes old checkpoints.  (cutting)


Release 0.11.2 - 2007-02-16

 1. HADOOP-1009.  Fix an infinite loop in the HDFS namenode.
    (Dhruba Borthakur via cutting) 

 2. HADOOP-1014.  Disable in-memory merging during shuffle, as this is
    causing data corruption.  (Devaraj Das via cutting)


Release 0.11.1 - 2007-02-09

 1. HADOOP-976.  Make SequenceFile.Metadata public.  (Runping Qi via cutting)

 2. HADOOP-917.  Fix a NullPointerException in SequenceFile's merger
    with large map outputs.  (omalley via cutting)

 3. HADOOP-984.  Fix a bug in shuffle error handling introduced by
    HADOOP-331.  If a map output is unavailable, the job tracker is
    once more informed.  (Arun C Murthy via cutting)

 4. HADOOP-987.  Fix a problem in HDFS where blocks were not removed
    from neededReplications after a replication target was selected.
    (Hairong Kuang via cutting)

Release 0.11.0 - 2007-02-02

 1. HADOOP-781.  Remove methods deprecated in 0.10 that are no longer
    widely used.  (cutting)

 2. HADOOP-842.  Change HDFS protocol so that the open() method is
    passed the client hostname, to permit the namenode to order block
    locations on the basis of network topology.
    (Hairong Kuang via cutting)

 3. HADOOP-852.  Add an ant task to compile record definitions, and
    use it to compile record unit tests.  (Milind Bhandarkar via cutting)

 4. HADOOP-757.  Fix "Bad File Descriptor" exception in HDFS client
    when an output file is closed twice.  (Raghu Angadi via cutting)

 5. [ intentionally blank ]

 6. HADOOP-890.  Replace dashes in metric names with underscores,
    for better compatibility with some monitoring systems.
    (Nigel Daley via cutting)

 7. HADOOP-801.  Add to jobtracker a log of task completion events.
    (Sanjay Dahiya via cutting)

 8. HADOOP-855.  In HDFS, try to repair files with checksum errors.
    An exception is still thrown, but corrupt blocks are now removed
    when they have replicas.  (Wendy Chien via cutting)

 9. HADOOP-886.  Reduce number of timer threads created by metrics API
    by pooling contexts.  (Nigel Daley via cutting)

10. HADOOP-897.  Add a "javac.args" property to build.xml that permits
    one to pass arbitrary options to javac. (Milind Bhandarkar via cutting)

11. HADOOP-899.  Update libhdfs for changes in HADOOP-871.
    (Sameer Paranjpye via cutting)

12. HADOOP-905.  Remove some dead code from JobClient.  (cutting)

13. HADOOP-902.  Fix a NullPointerException in HDFS client when
    closing output streams.  (Raghu Angadi via cutting)

14. HADOOP-735.  Switch generated record code to use BytesWritable to
    represent fields of type 'buffer'. (Milind Bhandarkar via cutting)

15. HADOOP-830.  Improve mapreduce merge performance by buffering and
    merging multiple map outputs as they arrive at reduce nodes before
    they're written to disk.  (Devaraj Das via cutting)

16. HADOOP-908.  Add a new contrib package, Abacus, that simplifies
    counting and aggregation, built on MapReduce.  (Runping Qi via cutting)

17. HADOOP-901.  Add support for recursive renaming to the S3 filesystem.
    (Tom White via cutting)

18. HADOOP-912.  Fix a bug in TaskTracker.isIdle() that was
    sporadically causing unit test failures.  (Arun C Murthy via cutting)

19. HADOOP-909.  Fix the 'du' command to correctly compute the size of
    FileSystem directory trees.  (Hairong Kuang via cutting)

20. HADOOP-731.  When a checksum error is encountered on a file stored
    in HDFS, try another replica of the data, if any.
    (Wendy Chien via cutting)

21. HADOOP-732.  Add support to SequenceFile for arbitrary metadata,
    as a set of attribute value pairs.  (Runping Qi via cutting)

22. HADOOP-929.  Fix PhasedFileSystem to pass configuration to
    underlying FileSystem.  (Sanjay Dahiya via cutting)

23. HADOOP-935.  Fix contrib/abacus to not delete pre-existing output
    files, but rather to fail in this case.  (Runping Qi via cutting)

24. HADOOP-936.  More metric renamings, as in HADOOP-890.
    (Nigel Daley via cutting)

25. HADOOP-856.  Fix HDFS's fsck command to not report that
    non-existent filesystems are healthy.  (Milind Bhandarkar via cutting)

26. HADOOP-602.  Remove the dependency on Lucene's PriorityQueue
    utility, by copying it into Hadoop.  This facilitates using Hadoop
    with different versions of Lucene without worrying about CLASSPATH
    order.  (Milind Bhandarkar via cutting)

27. [ intentionally blank ]

28. HADOOP-227.  Add support for backup namenodes, which periodically
    get snapshots of the namenode state.  (Dhruba Borthakur via cutting) 

29. HADOOP-884.  Add scripts in contrib/ec2 to facilitate running
    Hadoop on an Amazon's EC2 cluster.  (Tom White via cutting)

30. HADOOP-937.  Change the namenode to request re-registration of
    datanodes in more circumstances.  (Hairong Kuang via cutting)

31. HADOOP-922.  Optimize small forward seeks in HDFS.  If data is has
    likely already in flight, skip ahead rather than re-opening the
    block.  (Dhruba Borthakur via cutting)

32. HADOOP-961.  Add a 'job -events' sub-command that prints job
    events, including task completions and failures.  (omalley via cutting)

33. HADOOP-959.  Fix namenode snapshot code added in HADOOP-227 to
    work on Windows.  (Dhruba Borthakur via cutting)

34. HADOOP-934.  Fix TaskTracker to catch metrics exceptions that were
    causing heartbeats to fail.  (Arun Murthy via cutting)

35. HADOOP-881.  Fix JobTracker web interface to display the correct
    number of task failures.  (Sanjay Dahiya via cutting)

36. HADOOP-788.  Change contrib/streaming to subclass TextInputFormat,
    permitting it to take advantage of native compression facilities.
    (Sanjay Dahiya via cutting)

37. HADOOP-962.  In contrib/ec2: make scripts executable in tar file;
    add a README; make the environment file use a template.
    (Tom White via cutting)

38. HADOOP-549.  Fix a NullPointerException in TaskReport's
    serialization.  (omalley via cutting)

39. HADOOP-963.  Fix remote exceptions to have the stack trace of the
    caller thread, not the IPC listener thread.  (omalley via cutting)

40. HADOOP-967.  Change RPC clients to start sending a version header.
    (omalley via cutting)

41. HADOOP-964.  Fix a bug introduced by HADOOP-830 where jobs failed
    whose comparators and/or i/o types were in the job's jar.
    (Dennis Kubes via cutting)

42. HADOOP-969.  Fix a deadlock in JobTracker.  (omalley via cutting)

43. HADOOP-862.  Add support for the S3 FileSystem to the CopyFiles
    tool.  (Michael Stack via cutting)

44. HADOOP-965.  Fix IsolationRunner so that job's jar can be found.
    (Dennis Kubes via cutting)

45. HADOOP-309.  Fix two NullPointerExceptions in StatusHttpServer.
    (navychen via cutting)

46. HADOOP-692.  Add rack awareness to HDFS's placement of blocks.
    (Hairong Kuang via cutting)


Release 0.10.1 - 2007-01-10

 1. HADOOP-857.  Fix S3 FileSystem implementation to permit its use
    for MapReduce input and output.  (Tom White via cutting)

 2. HADOOP-863.  Reduce logging verbosity introduced by HADOOP-813.
    (Devaraj Das via cutting)

 3. HADOOP-815.  Fix memory leaks in JobTracker. (Arun C Murthy via cutting)

 4. HADOOP-600.  Fix a race condition in JobTracker.
    (Arun C Murthy via cutting)

 5. HADOOP-864.  Fix 'bin/hadoop -jar' to operate correctly when
    hadoop.tmp.dir does not yet exist.  (omalley via cutting)

 6. HADOOP-866.  Fix 'dfs -get' command to remove existing crc files,
    if any.  (Milind Bhandarkar via cutting)

 7. HADOOP-871.  Fix a bug in bin/hadoop setting JAVA_LIBRARY_PATH.
    (Arun C Murthy via cutting)

 8. HADOOP-868.  Decrease the number of open files during map,
    respecting io.sort.fa ctor.  (Devaraj Das via cutting)

 9. HADOOP-865.  Fix S3 FileSystem so that partially created files can
    be deleted.  (Tom White via cutting)

10. HADOOP-873.	 Pass java.library.path correctly to child processes.
    (omalley via cutting)

11. HADOOP-851.  Add support for the LZO codec.  This is much faster
    than the default, zlib-based compression, but it is only available
    when the native library is built.  (Arun C Murthy via cutting)

12. HADOOP-880.  Fix S3 FileSystem to remove directories.
    (Tom White via cutting)

13. HADOOP-879.  Fix InputFormatBase to handle output generated by
    MapFileOutputFormat.  (cutting)

14. HADOOP-659.  In HDFS, prioritize replication of blocks based on
    current replication level.  Blocks which are severely
    under-replicated should be further replicated before blocks which
    are less under-replicated.  (Hairong Kuang via cutting)

15. HADOOP-726.  Deprecate FileSystem locking methods.  They are not
    currently usable.  Locking should eventually provided as an
    independent service.  (Raghu Angadi via cutting)

16. HADOOP-758.  Fix exception handling during reduce so that root
    exceptions are not masked by exceptions in cleanups.
    (Raghu Angadi via cutting)


Release 0.10.0 - 2007-01-05

 1. HADOOP-763. Change DFS namenode benchmark to not use MapReduce.
    (Nigel Daley via cutting)

 2. HADOOP-777. Use fully-qualified hostnames for tasktrackers and
    datanodes.  (Mahadev Konar via cutting)

 3. HADOOP-621. Change 'dfs -cat' to exit sooner when output has been
    closed.  (Dhruba Borthakur via cutting) 

 4. HADOOP-752. Rationalize some synchronization in DFS namenode.
    (Dhruba Borthakur via cutting) 

 5. HADOOP-629. Fix RPC services to better check the protocol name and
    version.  (omalley via cutting)

 6. HADOOP-774. Limit the number of invalid blocks returned with
    heartbeats by the namenode to datanodes.  Transmitting and
    processing very large invalid block lists can tie up both the
    namenode and datanode for too long.  (Dhruba Borthakur via cutting) 

 7. HADOOP-738. Change 'dfs -get' command to not create CRC files by
    default, adding a -crc option to force their creation.
    (Milind Bhandarkar via cutting)

 8. HADOOP-676. Improved exceptions and error messages for common job
    input specification errors.  (Sanjay Dahiya via cutting)

 9. [Included in 0.9.2 release]

10. HADOOP-756. Add new dfsadmin option to wait for filesystem to be
    operational.  (Dhruba Borthakur via cutting)

11. HADOOP-770. Fix jobtracker web interface to display, on restart,
    jobs that were running when it was last stopped.
    (Sanjay Dahiya via cutting)

12. HADOOP-331. Write all map outputs to a single file with an index,
    rather than to a separate file per reduce task.  This should both
    speed the shuffle and make things more scalable.
    (Devaraj Das via cutting)

13. HADOOP-818. Fix contrib unit tests to not depend on core unit
    tests.  (omalley via cutting)

14. HADOOP-786. Log common exception at debug level.
    (Sanjay Dahiya via cutting)

15. HADOOP-796. Provide more convenient access to failed task
    information in the web interface.  (Sanjay Dahiya via cutting)

16. HADOOP-764. Reduce memory allocations in namenode some.
    (Dhruba Borthakur via cutting) 

17. HADOOP-802. Update description of mapred.speculative.execution to
    mention reduces.  (Nigel Daley via cutting)

18. HADOOP-806. Include link to datanodes on front page of namenode
    web interface.  (Raghu Angadi via cutting)

19. HADOOP-618.  Make JobSubmissionProtocol public.
    (Arun C Murthy via cutting)

20. HADOOP-782.  Fully remove killed tasks.  (Arun C Murthy via cutting)

21. HADOOP-792.  Fix 'dfs -mv' to return correct status.
    (Dhruba Borthakur via cutting) 

22. HADOOP-673.  Give each task its own working directory again.
    (Mahadev Konar via cutting)

23. HADOOP-571.  Extend the syntax of Path to be a URI; to be
    optionally qualified with a scheme and authority.  The scheme
    determines the FileSystem implementation, while the authority
    determines the FileSystem instance.  New FileSystem
    implementations may be provided by defining an fs.<scheme>.impl
    property, naming the FileSystem implementation class.  This
    permits easy integration of new FileSystem implementations.
    (cutting)

24. HADOOP-720.  Add an HDFS white paper to website.
    (Dhruba Borthakur via cutting) 

25. HADOOP-794.  Fix a divide-by-zero exception when a job specifies
    zero map tasks.  (omalley via cutting)

26. HADOOP-454.  Add a 'dfs -dus' command that provides summary disk
    usage.  (Hairong Kuang via cutting)

27. HADOOP-574.  Add an Amazon S3 implementation of FileSystem.  To
    use this, one need only specify paths of the form
    s3://id:secret@bucket/.  Alternately, the AWS access key id and
    secret can be specified in your config, with the properties
    fs.s3.awsAccessKeyId and fs.s3.awsSecretAccessKey.
    (Tom White via cutting)

28. HADOOP-824.  Rename DFSShell to be FsShell, since it applies
    generically to all FileSystem implementations.  (cutting)

29. HADOOP-813.  Fix map output sorting to report progress, so that
    sorts which take longer than the task timeout do not fail.
    (Devaraj Das via cutting)

30. HADOOP-825.  Fix HDFS daemons when configured with new URI syntax.
    (omalley via cutting)

31. HADOOP-596.  Fix a bug in phase reporting during reduce.
    (Sanjay Dahiya via cutting)

32. HADOOP-811.  Add a utility, MultithreadedMapRunner.
    (Alejandro Abdelnur via cutting)

33. HADOOP-829.  Within HDFS, clearly separate three different
    representations for datanodes: one for RPCs, one for
    namenode-internal use, and one for namespace persistence.
    (Dhruba Borthakur via cutting) 

34. HADOOP-823.  Fix problem starting datanode when not all configured
    data directories exist.  (Bryan Pendleton via cutting)

35. HADOOP-451.  Add a Split interface.  CAUTION: This incompatibly
    changes the InputFormat and RecordReader interfaces.  Not only is
    FileSplit replaced with Split, but a FileSystem parameter is no
    longer passed in several methods, input validation has changed,
    etc.  (omalley via cutting)

36. HADOOP-814.  Optimize locking in namenode. (Dhruba Borthakur via cutting) 

37. HADOOP-738.  Change 'fs -put' and 'fs -get' commands to accept
    standard input and output, respectively.  Standard i/o is
    specified by a file named '-'.  (Wendy Chien via cutting)

38. HADOOP-835.  Fix a NullPointerException reading record-compressed
    SequenceFiles.  (Hairong Kuang via cutting)

39. HADOOP-836.  Fix a MapReduce bug on Windows, where the wrong
    FileSystem was used.  Also add a static FileSystem.getLocal()
    method and better Path checking in HDFS, to help avoid such issues
    in the future.  (omalley via cutting)

40. HADOOP-837.  Improve RunJar utility to unpack jar file
    hadoop.tmp.dir, rather than the system temporary directory.
    (Hairong Kuang via cutting)

41. HADOOP-841.  Fix native library to build 32-bit version even when
    on a 64-bit host, if a 32-bit JVM is used.  (Arun C Murthy via cutting)

42. HADOOP-838.  Fix tasktracker to pass java.library.path to
    sub-processes, so that libhadoop.a is found.
    (Arun C Murthy via cutting)

43. HADOOP-844.  Send metrics messages on a fixed-delay schedule
    instead of a fixed-rate schedule.  (David Bowen via cutting)

44. HADOOP-849.  Fix OutOfMemory exceptions in TaskTracker due to a
    file handle leak in SequenceFile.  (Devaraj Das via cutting)

45. HADOOP-745.  Fix a synchronization bug in the HDFS namenode.
    (Dhruba Borthakur via cutting)

46. HADOOP-850.  Add Writable implementations for variable-length
    integers.  (ab via cutting)

47. HADOOP-525.  Add raw comparators to record types.  This greatly
    improves record sort performance.  (Milind Bhandarkar via cutting)

48. HADOOP-628.  Fix a problem with 'fs -cat' command, where some
    characters were replaced with question marks.  (Wendy Chien via cutting)

49. HADOOP-804.  Reduce verbosity of MapReduce logging.
    (Sanjay Dahiya via cutting)

50. HADOOP-853.  Rename 'site' to 'docs', in preparation for inclusion
    in releases.  (cutting)

51. HADOOP-371.  Include contrib jars and site documentation in
    distributions.  Also add contrib and example documentation to
    distributed javadoc, in separate sections.  (Nigel Daley via cutting)

52. HADOOP-846.  Report progress during entire map, as sorting of
    intermediate outputs may happen at any time, potentially causing
    task timeouts.  (Devaraj Das via cutting)

53. HADOOP-840.  In task tracker, queue task cleanups and perform them
    in a separate thread.  (omalley & Mahadev Konar via cutting)

54. HADOOP-681.  Add to HDFS the ability to decommission nodes.  This
    causes their blocks to be re-replicated on other nodes, so that
    they may be removed from a cluster.  (Dhruba Borthakur via cutting)

55. HADOOP-470.  In HDFS web ui, list the datanodes containing each
    copy of a block.  (Hairong Kuang via cutting)

56. HADOOP-700.  Change bin/hadoop to only include core jar file on
    classpath, not example, test, etc.  Also rename core jar to
    hadoop-${version}-core.jar so that it can be more easily
    identified.  (Nigel Daley via cutting)

57. HADOOP-619.  Extend InputFormatBase to accept individual files and
    glob patterns as MapReduce inputs, not just directories.  Also
    change contrib/streaming to use this.  (Sanjay Dahia via cutting)


Release 0.9.2 - 2006-12-15

 1. HADOOP-639. Restructure InterTrackerProtocol to make task
    accounting more reliable.  (Arun C Murthy via cutting)

 2. HADOOP-827. Turn off speculative execution by default, since it's
    currently broken.  (omalley via cutting)

 3. HADOOP-791. Fix a deadlock in the task tracker.
    (Mahadev Konar via cutting)


Release 0.9.1 - 2006-12-06

 1. HADOOP-780. Use ReflectionUtils to instantiate key and value
    objects. (ab)

 2. HADOOP-779. Fix contrib/streaming to work correctly with gzipped
    input files.  (Hairong Kuang via cutting)


Release 0.9.0 - 2006-12-01

 1. HADOOP-655.  Remove most deprecated code.  A few deprecated things
    remain, notably UTF8 and some methods that are still required.
    Also cleaned up constructors for SequenceFile, MapFile, SetFile,
    and ArrayFile a bit.  (cutting)

 2. HADOOP-565.  Upgrade to Jetty version 6. (Sanjay Dahiya via cutting)

 3. HADOOP-682.  Fix DFS format command to work correctly when
    configured with a non-existent directory. (Sanjay Dahiya via cutting)

 4. HADOOP-645.  Fix a bug in contrib/streaming when -reducer is NONE.
    (Dhruba Borthakur via cutting) 

 5. HADOOP-687.  Fix a classpath bug in bin/hadoop that blocked the
    servers from starting. (Sameer Paranjpye via omalley)

 6. HADOOP-683.  Remove a script dependency on bash, so it works with
    dash, the new default for /bin/sh on Ubuntu.  (James Todd via cutting)

 7. HADOOP-382.  Extend unit tests to run multiple datanodes.
    (Milind Bhandarkar via cutting)

 8. HADOOP-604.  Fix some synchronization issues and a
    NullPointerException in DFS datanode.  (Raghu Angadi via cutting)

 9. HADOOP-459.  Fix memory leaks and a host of other issues with
    libhdfs.  (Sameer Paranjpye via cutting)

10. HADOOP-694.  Fix a NullPointerException in jobtracker.
    (Mahadev Konar via cutting)

11. HADOOP-637.  Fix a memory leak in the IPC server.  Direct buffers
    are not collected like normal buffers, and provided little
    advantage.  (Raghu Angadi via cutting)

12. HADOOP-696.  Fix TestTextInputFormat unit test to not rely on the
    order of directory listings.  (Sameer Paranjpye via cutting)

13. HADOOP-611.  Add support for iterator-based merging to
    SequenceFile.  (Devaraj Das via cutting)

14. HADOOP-688.  Move DFS administrative commands to a separate
    command named 'dfsadmin'.  (Dhruba Borthakur via cutting) 

15. HADOOP-708.  Fix test-libhdfs to return the correct status, so
    that failures will break the build.  (Nigel Daley via cutting)

16. HADOOP-646.  Fix namenode to handle edits files larger than 2GB.
    (Milind Bhandarkar via cutting)

17. HADOOP-705.  Fix a bug in the JobTracker when failed jobs were
    not completely cleaned up.  (Mahadev Konar via cutting)

18. HADOOP-613.  Perform final merge while reducing.  This removes one
    sort pass over the data and should consequently significantly
    decrease overall processing time.  (Devaraj Das via cutting)

19. HADOOP-661.  Make each job's configuration visible through the web
    ui.  (Arun C Murthy via cutting)

20. HADOOP-489.  In MapReduce, separate user logs from system logs.
    Each task's log output is now available through the web ui.  (Arun
    C Murthy via cutting)

21. HADOOP-712.  Fix record io's xml serialization to correctly handle
    control-characters.  (Milind Bhandarkar via cutting)

22. HADOOP-668.  Improvements to the web-based DFS browser.
    (Hairong Kuang via cutting)

23. HADOOP-715.  Fix build.xml so that test logs are written in build
    directory, rather than in CWD.  (Arun C Murthy via cutting)

24. HADOOP-538.  Add support for building an optional native library,
    libhadoop.so, that improves the performance of zlib-based
    compression.  To build this, specify -Dcompile.native to Ant.
    (Arun C Murthy via cutting)

25. HADOOP-610.  Fix an problem when the DFS block size is configured
    to be smaller than the buffer size, typically only when debugging.
    (Milind Bhandarkar via cutting)

26. HADOOP-695.  Fix a NullPointerException in contrib/streaming.
    (Hairong Kuang via cutting)

27. HADOOP-652.  In DFS, when a file is deleted, the block count is
    now decremented.  (Vladimir Krokhmalyov via cutting)

28. HADOOP-725.  In DFS, optimize block placement algorithm,
    previously a performance bottleneck.  (Milind Bhandarkar via cutting)

29. HADOOP-723.  In MapReduce, fix a race condition during the
    shuffle, which resulted in FileNotFoundExceptions.  (omalley via cutting)

30. HADOOP-447.  In DFS, fix getBlockSize(Path) to work with relative
    paths.  (Raghu Angadi via cutting)

31. HADOOP-733.  Make exit codes in DFShell consistent and add a unit
    test.  (Dhruba Borthakur via cutting)

32. HADOOP-709.  Fix contrib/streaming to work with commands that
    contain control characters.  (Dhruba Borthakur via cutting)

33. HADOOP-677.  In IPC, permit a version header to be transmitted
    when connections are established.  This will permit us to change
    the format of IPC requests back-compatibly in subsequent releases.
    (omalley via cutting)

34. HADOOP-699.  Fix DFS web interface so that filesystem browsing
    works correctly, using the right port number.  Also add support
    for sorting datanode list by various columns.
    (Raghu Angadi via cutting)

35. HADOOP-76.  Implement speculative reduce.  Now when a job is
    configured for speculative execution, both maps and reduces will
    execute speculatively.  Reduce outputs are written to temporary
    location and moved to the final location when reduce is complete.
    (Sanjay Dahiya via cutting)

36. HADOOP-736.  Roll back to Jetty 5.1.4, due to performance problems
    with Jetty 6.0.1.

37. HADOOP-739.  Fix TestIPC to use different port number, making it
    more reliable.  (Nigel Daley via cutting)

38. HADOOP-749.  Fix a NullPointerException in jobfailures.jsp.
    (omalley via cutting)

39. HADOOP-747.  Fix record serialization to work correctly when
    records are embedded in Maps.  (Milind Bhandarkar via cutting)

40. HADOOP-698.  Fix HDFS client not to retry the same datanode on
    read failures.  (Milind Bhandarkar via cutting)

41. HADOOP-689. Add GenericWritable, to facilitate polymorphism in
    MapReduce, SequenceFile, etc. (Feng Jiang via cutting)

42. HADOOP-430.  Stop datanode's HTTP server when registration with
    namenode fails.  (Wendy Chien via cutting)

43. HADOOP-750.  Fix a potential race condition during mapreduce
    shuffle.  (omalley via cutting)

44. HADOOP-728.  Fix contrib/streaming-related issues, including
    '-reducer NONE'.  (Sanjay Dahiya via cutting)


Release 0.8.0 - 2006-11-03

 1. HADOOP-477.  Extend contrib/streaming to scan the PATH environment
    variables when resolving executable program names.
    (Dhruba Borthakur via cutting) 

 2. HADOOP-583.  In DFSClient, reduce the log level of re-connect
    attempts from 'info' to 'debug', so they are not normally shown.
    (Konstantin Shvachko via cutting)

 3. HADOOP-498.  Re-implement DFS integrity checker to run server-side,
    for much improved performance.  (Milind Bhandarkar via cutting)

 4. HADOOP-586.  Use the jar name for otherwise un-named jobs.
    (Sanjay Dahiya via cutting)

 5. HADOOP-514.  Make DFS heartbeat interval configurable.
    (Milind Bhandarkar via cutting)

 6. HADOOP-588.  Fix logging and accounting of failed tasks.
    (Sanjay Dahiya via cutting)

 7. HADOOP-462.  Improve command line parsing in DFSShell, so that
    incorrect numbers of arguments result in informative errors rather
    than ArrayOutOfBoundsException.  (Dhruba Borthakur via cutting) 

 8. HADOOP-561.  Fix DFS so that one replica of each block is written
    locally, if possible.  This was the intent, but there as a bug.
    (Dhruba Borthakur via cutting) 

 9. HADOOP-610.  Fix TaskTracker to survive more exceptions, keeping
    tasks from becoming lost.  (omalley via cutting)

10. HADOOP-625.  Add a servlet to all http daemons that displays a
    stack dump, useful for debugging.  (omalley via cutting)

11. HADOOP-554.  Fix DFSShell to return -1 for errors.
    (Dhruba Borthakur via cutting) 

12. HADOOP-626.  Correct the documentation in the NNBench example
    code, and also remove a mistaken call there.
    (Nigel Daley via cutting)

13. HADOOP-634.  Add missing license to many files.
    (Nigel Daley via cutting)

14. HADOOP-627.  Fix some synchronization problems in MiniMRCluster
    that sometimes caused unit tests to fail.  (Nigel Daley via cutting)

15. HADOOP-563.  Improve the NameNode's lease policy so that leases
    are held for one hour without renewal (instead of one minute).
    However another attempt to create the same file will still succeed
    if the lease has not been renewed within a minute.  This prevents
    communication or scheduling problems from causing a write to fail
    for up to an hour, barring some other process trying to create the
    same file.  (Dhruba Borthakur via cutting)

16. HADOOP-635.  In DFSShell, permit specification of multiple files
    as the source for file copy and move commands.
    (Dhruba Borthakur via cutting)

17. HADOOP-641.  Change NameNode to request a fresh block report from
    a re-discovered DataNode, so that no-longer-needed replications
    are stopped promptly.  (Konstantin Shvachko via cutting)

18. HADOOP-642.  Change IPC client to specify an explicit connect
    timeout.  (Konstantin Shvachko via cutting)

19. HADOOP-638.  Fix an unsynchronized access to TaskTracker's
    internal state.  (Nigel Daley via cutting)

20. HADOOP-624.  Fix servlet path to stop a Jetty warning on startup.
    (omalley via cutting)

21. HADOOP-578.  Failed tasks are no longer placed at the end of the
    task queue.  This was originally done to work around other
    problems that have now been fixed.  Re-executing failed tasks
    sooner causes buggy jobs to fail faster.  (Sanjay Dahiya via cutting)

22. HADOOP-658.  Update source file headers per Apache policy.  (cutting)

23. HADOOP-636.  Add MapFile & ArrayFile constructors which accept a
    Progressable, and pass it down to SequenceFile.  This permits
    reduce tasks which use MapFile to still report progress while
    writing blocks to the filesystem.  (cutting)

24. HADOOP-576.  Enable contrib/streaming to use the file cache.  Also
    extend the cache to permit symbolic links to cached items, rather
    than local file copies.  (Mahadev Konar via cutting)

25. HADOOP-482.  Fix unit tests to work when a cluster is running on
    the same machine, removing port conflicts.  (Wendy Chien via cutting)

26. HADOOP-90.  Permit dfs.name.dir to list multiple directories,
    where namenode data is to be replicated. (Milind Bhandarkar via cutting)

27. HADOOP-651.  Fix DFSCk to correctly pass parameters to the servlet
    on the namenode.  (Milind Bhandarkar via cutting)

28. HADOOP-553.  Change main() routines of DataNode and NameNode to
    log exceptions rather than letting the JVM print them to standard
    error.  Also, change the hadoop-daemon.sh script to rotate
    standard i/o log files.  (Raghu Angadi via cutting)

29. HADOOP-399.  Fix javadoc warnings.  (Nigel Daley via cutting)

30. HADOOP-599.  Fix web ui and command line to correctly report DFS
    filesystem size statistics.  Also improve web layout.
    (Raghu Angadi via cutting)

31. HADOOP-660.  Permit specification of junit test output format.
    (Nigel Daley via cutting)

32. HADOOP-663.  Fix a few unit test issues.  (Mahadev Konar via cutting)

33. HADOOP-664.  Cause entire build to fail if libhdfs tests fail.
    (Nigel Daley via cutting)

34. HADOOP-633.  Keep jobtracker from dying when job initialization
    throws exceptions.  Also improve exception handling in a few other
    places and add more informative thread names.
    (omalley via cutting)

35. HADOOP-669.  Fix a problem introduced by HADOOP-90 that can cause
    DFS to lose files.  (Milind Bhandarkar via cutting)

36. HADOOP-373.  Consistently check the value returned by
    FileSystem.mkdirs().  (Wendy Chien via cutting)

37. HADOOP-670.  Code cleanups in some DFS internals: use generic
    types, replace Vector with ArrayList, etc.
    (Konstantin Shvachko via cutting)

38. HADOOP-647.  Permit map outputs to use a different compression
    type than the job output.  (omalley via cutting)

39. HADOOP-671.  Fix file cache to check for pre-existence before
    creating .  (Mahadev Konar via cutting)

40. HADOOP-665.  Extend many DFSShell commands to accept multiple
    arguments.  Now commands like "ls", "rm", etc. will operate on
    multiple files.  (Dhruba Borthakur via cutting)


Release 0.7.2 - 2006-10-18

 1. HADOOP-607.  Fix a bug where classes included in job jars were not
    found by tasks.  (Mahadev Konar via cutting)

 2. HADOOP-609.  Add a unit test that checks that classes in job jars
    can be found by tasks.  Also modify unit tests to specify multiple
    local directories.  (Mahadev Konar via cutting)


Release 0.7.1 - 2006-10-11

 1. HADOOP-593.  Fix a NullPointerException in the JobTracker.
    (omalley via cutting)

 2. HADOOP-592.  Fix a NullPointerException in the IPC Server.  Also
    consistently log when stale calls are discarded.  (omalley via cutting)

 3. HADOOP-594.  Increase the DFS safe-mode threshold from .95 to
    .999, so that nearly all blocks must be reported before filesystem
    modifications are permitted.  (Konstantin Shvachko via cutting)

 4. HADOOP-598.  Fix tasks to retry when reporting completion, so that
    a single RPC timeout won't fail a task.  (omalley via cutting)

 5. HADOOP-597.  Fix TaskTracker to not discard map outputs for errors
    in transmitting them to reduce nodes.  (omalley via cutting)


Release 0.7.0 - 2006-10-06

 1. HADOOP-243.  Fix rounding in the display of task and job progress
    so that things are not shown to be 100% complete until they are in
    fact finished.  (omalley via cutting) 

 2. HADOOP-438.  Limit the length of absolute paths in DFS, since the
    file format used to store pathnames has some limitations.
    (Wendy Chien via cutting)

 3. HADOOP-530.  Improve error messages in SequenceFile when keys or
    values are of the wrong type.  (Hairong Kuang via cutting)

 4. HADOOP-288.  Add a file caching system and use it in MapReduce to
    cache job jar files on slave nodes.  (Mahadev Konar via cutting)

 5. HADOOP-533.  Fix unit test to not modify conf directory.
   (Hairong Kuang via cutting)

 6. HADOOP-527.  Permit specification of the local address that various
    Hadoop daemons should bind to.  (Philippe Gassmann via cutting)

 7. HADOOP-542.  Updates to contrib/streaming: reformatted source code,
    on-the-fly merge sort, a fix for HADOOP-540, etc.
    (Michel Tourn via cutting)

 8. HADOOP-545.  Remove an unused config file parameter.
    (Philippe Gassmann via cutting)

 9. HADOOP-548.  Add an Ant property "test.output" to build.xml that
    causes test output to be logged to the console.  (omalley via cutting)

10. HADOOP-261.  Record an error message when map output is lost.
    (omalley via cutting)

11. HADOOP-293.  Report the full list of task error messages in the
    web ui, not just the most recent.  (omalley via cutting)

12. HADOOP-551.  Restore JobClient's console printouts to only include
    a maximum of one update per one percent of progress.
    (omalley via cutting)

13. HADOOP-306.  Add a "safe" mode to DFS.  The name node enters this
    when less than a specified percentage of file data is complete.
    Currently safe mode is only used on startup, but eventually it
    will also be entered when datanodes disconnect and file data
    becomes incomplete.  While in safe mode no filesystem
    modifications are permitted and block replication is inhibited.
    (Konstantin Shvachko via cutting)

14. HADOOP-431.  Change 'dfs -rm' to not operate recursively and add a
    new command, 'dfs -rmr' which operates recursively.
    (Sameer Paranjpye via cutting)

15. HADOOP-263.  Include timestamps for job transitions.  The web
    interface now displays the start and end times of tasks and the
    start times of sorting and reducing for reduce tasks.  Also,
    extend ObjectWritable to handle enums, so that they can be passed
    as RPC parameters.  (Sanjay Dahiya via cutting)

16. HADOOP-556.  Contrib/streaming: send keep-alive reports to task
    tracker every 10 seconds rather than every 100 records, to avoid
    task timeouts.  (Michel Tourn via cutting)

17. HADOOP-547.  Fix reduce tasks to ping tasktracker while copying
    data, rather than only between copies, avoiding task timeouts.
    (Sanjay Dahiya via cutting)

18. HADOOP-537.  Fix src/c++/libhdfs build process to create files in
    build/, no longer modifying the source tree.
    (Arun C Murthy via cutting)

19. HADOOP-487.  Throw a more informative exception for unknown RPC
    hosts.  (Sameer Paranjpye via cutting)

20. HADOOP-559.  Add file name globbing (pattern matching) support to
    the FileSystem API, and use it in DFSShell ('bin/hadoop dfs')
    commands.  (Hairong Kuang via cutting)

21. HADOOP-508.  Fix a bug in FSDataInputStream.  Incorrect data was
    returned after seeking to a random location.
    (Milind Bhandarkar via cutting)

22. HADOOP-560.  Add a "killed" task state.  This can be used to
    distinguish kills from other failures.  Task state has also been
    converted to use an enum type instead of an int, uncovering a bug
    elsewhere.  The web interface is also updated to display killed
    tasks.  (omalley via cutting)

23. HADOOP-423.  Normalize Paths containing directories named "." and
    "..", using the standard, unix interpretation.  Also add checks in
    DFS, prohibiting the use of "." or ".." as directory or file
    names.  (Wendy Chien via cutting)

24. HADOOP-513.  Replace map output handling with a servlet, rather
    than a JSP page.  This fixes an issue where
    IllegalStateException's were logged, sets content-length
    correctly, and better handles some errors.  (omalley via cutting)

25. HADOOP-552.  Improved error checking when copying map output files
    to reduce nodes.  (omalley via cutting)

26. HADOOP-566.  Fix scripts to work correctly when accessed through
    relative symbolic links.  (Lee Faris via cutting)

27. HADOOP-519.  Add positioned read methods to FSInputStream.  These
    permit one to read from a stream without moving its position, and
    can hence be performed by multiple threads at once on a single
    stream. Implement an optimized version for DFS and local FS.
    (Milind Bhandarkar via cutting)

28. HADOOP-522. Permit block compression with MapFile and SetFile.
    Since these formats are always sorted, block compression can
    provide a big advantage.  (cutting)

29. HADOOP-567. Record version and revision information in builds.  A
    package manifest is added to the generated jar file containing
    version information, and a VersionInfo utility is added that
    includes further information, including the build date and user,
    and the subversion revision and repository.  A 'bin/hadoop
    version' comand is added to show this information, and it is also
    added to various web interfaces.  (omalley via cutting)

30. HADOOP-568.  Fix so that errors while initializing tasks on a
    tasktracker correctly report the task as failed to the jobtracker,
    so that it will be rescheduled.  (omalley via cutting)

31. HADOOP-550.  Disable automatic UTF-8 validation in Text.  This
    permits, e.g., TextInputFormat to again operate on non-UTF-8 data.
    (Hairong and Mahadev via cutting)

32. HADOOP-343.  Fix mapred copying so that a failed tasktracker
    doesn't cause other copies to slow.  (Sameer Paranjpye via cutting)

33. HADOOP-239.  Add a persistent job history mechanism, so that basic
    job statistics are not lost after 24 hours and/or when the
    jobtracker is restarted.  (Sanjay Dahiya via cutting)

34. HADOOP-506.  Ignore heartbeats from stale task trackers.
   (Sanjay Dahiya via cutting)

35. HADOOP-255.  Discard stale, queued IPC calls.  Do not process
    calls whose clients will likely time out before they receive a
    response.  When the queue is full, new calls are now received and
    queued, and the oldest calls are discarded, so that, when servers
    get bogged down, they no longer develop a backlog on the socket.
    This should improve some DFS namenode failure modes.
    (omalley via cutting)

36. HADOOP-581.  Fix datanode to not reset itself on communications
    errors with the namenode.  If a request to the namenode fails, the
    datanode should retry, not restart.  This reduces the load on the
    namenode, since restarts cause a resend of the block report.
    (omalley via cutting)


Release 0.6.2 - 2006-09-18

1. HADOOP-532.  Fix a bug reading value-compressed sequence files,
   where an exception was thrown reporting that the full value had not
   been read.  (omalley via cutting)

2. HADOOP-534.  Change the default value class in JobConf to be Text
   instead of the now-deprecated UTF8.  This fixes the Grep example
   program, which was updated to use Text, but relies on this
   default.  (Hairong Kuang via cutting)


Release 0.6.1 - 2006-09-13

 1. HADOOP-520.  Fix a bug in libhdfs, where write failures were not
    correctly returning error codes.  (Arun C Murthy via cutting)

 2. HADOOP-523.  Fix a NullPointerException when TextInputFormat is
    explicitly specified.  Also add a test case for this.
    (omalley via cutting)

 3. HADOOP-521.  Fix another NullPointerException finding the
    ClassLoader when using libhdfs.  (omalley via cutting)

 4. HADOOP-526.  Fix a NullPointerException when attempting to start
    two datanodes in the same directory.  (Milind Bhandarkar via cutting)

 5. HADOOP-529.  Fix a NullPointerException when opening
    value-compressed sequence files generated by pre-0.6.0 Hadoop.
    (omalley via cutting)


Release 0.6.0 - 2006-09-08

 1. HADOOP-427.  Replace some uses of DatanodeDescriptor in the DFS
    web UI code with DatanodeInfo, the preferred public class.
    (Devaraj Das via cutting)

 2. HADOOP-426.  Fix streaming contrib module to work correctly on
    Solaris.  This was causing nightly builds to fail.
    (Michel Tourn via cutting)

 3. HADOOP-400.  Improvements to task assignment.  Tasks are no longer
    re-run on nodes where they have failed (unless no other node is
    available).  Also, tasks are better load-balanced among nodes.
    (omalley via cutting)

 4. HADOOP-324.  Fix datanode to not exit when a disk is full, but
    rather simply to fail writes.  (Wendy Chien via cutting)

 5. HADOOP-434.  Change smallJobsBenchmark to use standard Hadoop
    scripts.  (Sanjay Dahiya via cutting)

 6. HADOOP-453.  Fix a bug in Text.setCapacity().  (siren via cutting)


 7. HADOOP-450.  Change so that input types are determined by the
    RecordReader rather than specified directly in the JobConf.  This
    facilitates jobs with a variety of input types.

    WARNING: This contains incompatible API changes!  The RecordReader
    interface has two new methods that all user-defined InputFormats
    must now define.  Also, the values returned by TextInputFormat are
    no longer of class UTF8, but now of class Text.

 8. HADOOP-436.  Fix an error-handling bug in the web ui.
    (Devaraj Das via cutting)

 9. HADOOP-455.  Fix a bug in Text, where DEL was not permitted.
    (Hairong Kuang via cutting)

10. HADOOP-456.  Change the DFS namenode to keep a persistent record
    of the set of known datanodes.  This will be used to implement a
    "safe mode" where filesystem changes are prohibited when a
    critical percentage of the datanodes are unavailable.
    (Konstantin Shvachko via cutting)

11. HADOOP-322.  Add a job control utility.  This permits one to
    specify job interdependencies.  Each job is submitted only after
    the jobs it depends on have successfully completed.
    (Runping Qi via cutting)

12. HADOOP-176.  Fix a bug in IntWritable.Comparator.
    (Dick King via cutting)

13. HADOOP-421.  Replace uses of String in recordio package with Text
    class, for improved handling of UTF-8 data.
    (Milind Bhandarkar via cutting)

14. HADOOP-464.  Improved error message when job jar not found.
    (Michel Tourn via cutting)

15. HADOOP-469.  Fix /bin/bash specifics that have crept into our
    /bin/sh scripts since HADOOP-352.
    (Jean-Baptiste Quenot via cutting)

16. HADOOP-468.  Add HADOOP_NICENESS environment variable to set
    scheduling priority for daemons.  (Vetle Roeim via cutting)

17. HADOOP-473.  Fix TextInputFormat to correctly handle more EOL
    formats.  Things now work correctly with CR, LF or CRLF.
    (Dennis Kubes & James White via cutting)

18. HADOOP-461.  Make Java 1.5 an explicit requirement.  (cutting)

19. HADOOP-54.  Add block compression to SequenceFile.  One may now
    specify that blocks of keys and values are compressed together,
    improving compression for small keys and values.
    SequenceFile.Writer's constructor is now deprecated and replaced
    with a factory method.  (Arun C Murthy via cutting)

20. HADOOP-281.  Prohibit DFS files that are also directories.
    (Wendy Chien via cutting)

21. HADOOP-486.  Add the job username to JobStatus instances returned
    by JobClient.  (Mahadev Konar via cutting)

22. HADOOP-437.  contrib/streaming: Add support for gzipped inputs.
    (Michel Tourn via cutting)

23. HADOOP-463.  Add variable expansion to config files.
    Configuration property values may now contain variable
    expressions.  A variable is referenced with the syntax
    '${variable}'.  Variables values are found first in the
    configuration, and then in Java system properties.  The default
    configuration is modified so that temporary directories are now
    under ${hadoop.tmp.dir}, which is, by default,
    /tmp/hadoop-${user.name}.  (Michel Tourn via cutting)

24. HADOOP-419. Fix a NullPointerException finding the ClassLoader
    when using libhdfs.  (omalley via cutting)

25. HADOOP-460. Fix contrib/smallJobsBenchmark to use Text instead of
    UTF8.  (Sanjay Dahiya via cutting)

26. HADOOP-196.  Fix Configuration(Configuration) constructor to work
    correctly.  (Sami Siren via cutting)

27. HADOOP-501.  Fix Configuration.toString() to handle URL resources.
    (Thomas Friol via cutting)

28. HADOOP-499.  Reduce the use of Strings in contrib/streaming,
    replacing them with Text for better performance.
    (Hairong Kuang via cutting)

29. HADOOP-64.  Manage multiple volumes with a single DataNode.
    Previously DataNode would create a separate daemon per configured
    volume, each with its own connection to the NameNode.  Now all
    volumes are handled by a single DataNode daemon, reducing the load
    on the NameNode.  (Milind Bhandarkar via cutting)

30. HADOOP-424.  Fix MapReduce so that jobs which generate zero splits
    do not fail.  (Fr??d??ric Bertin via cutting)

31. HADOOP-408.  Adjust some timeouts and remove some others so that
    unit tests run faster.  (cutting)

32. HADOOP-507.  Fix an IllegalAccessException in DFS.
    (omalley via cutting)

33. HADOOP-320.  Fix so that checksum files are correctly copied when
    the destination of a file copy is a directory.
    (Hairong Kuang via cutting)

34. HADOOP-286.  In DFSClient, avoid pinging the NameNode with
    renewLease() calls when no files are being written.
    (Konstantin Shvachko via cutting)

35. HADOOP-312.  Close idle IPC connections.  All IPC connections were
    cached forever.  Now, after a connection has been idle for more
    than a configurable amount of time (one second by default), the
    connection is closed, conserving resources on both client and
    server. (Devaraj Das via cutting)

36. HADOOP-497.  Permit the specification of the network interface and
    nameserver to be used when determining the local hostname
    advertised by datanodes and tasktrackers.
    (Lorenzo Thione via cutting)

37. HADOOP-441.  Add a compression codec API and extend SequenceFile
    to use it.  This will permit the use of alternate compression
    codecs in SequenceFile.  (Arun C Murthy via cutting)

38. HADOOP-483. Improvements to libhdfs build and documentation.
    (Arun C Murthy via cutting)

39. HADOOP-458.  Fix a memory corruption bug in libhdfs.
    (Arun C Murthy via cutting)

40. HADOOP-517.  Fix a contrib/streaming bug in end-of-line detection.
    (Hairong Kuang via cutting)

41. HADOOP-474.  Add CompressionCodecFactory, and use it in
    TextInputFormat and TextOutputFormat.  Compressed input files are
    automatically decompressed when they have the correct extension.
    Output files will, when output compression is specified, be
    generated with an approprate extension.  Also add a gzip codec and
    fix problems with UTF8 text inputs.  (omalley via cutting)


Release 0.5.0 - 2006-08-04

 1. HADOOP-352.  Fix shell scripts to use /bin/sh instead of
    /bin/bash, for better portability.
    (Jean-Baptiste Quenot via cutting)

 2. HADOOP-313.  Permit task state to be saved so that single tasks
    may be manually re-executed when debugging.  (omalley via cutting)

 3. HADOOP-339.  Add method to JobClient API listing jobs that are
    not yet complete, i.e., that are queued or running.
    (Mahadev Konar via cutting)

 4. HADOOP-355.  Updates to the streaming contrib module, including
    API fixes, making reduce optional, and adding an input type for
    StreamSequenceRecordReader.  (Michel Tourn via cutting)

 5. HADOOP-358.  Fix a NPE bug in Path.equals().
    (Fr??d??ric Bertin via cutting)

 6. HADOOP-327.  Fix ToolBase to not call System.exit() when
    exceptions are thrown.  (Hairong Kuang via cutting)

 7. HADOOP-359.  Permit map output to be compressed.
    (omalley via cutting)

 8. HADOOP-341.  Permit input URI to CopyFiles to use the HTTP
    protocol.  This lets one, e.g., more easily copy log files into
    DFS.  (Arun C Murthy via cutting)

 9. HADOOP-361.  Remove unix dependencies from streaming contrib
    module tests, making them pure java. (Michel Tourn via cutting)

10. HADOOP-354.  Make public methods to stop DFS daemons.
    (Barry Kaplan via cutting)

11. HADOOP-252.  Add versioning to RPC protocols.
    (Milind Bhandarkar via cutting)

12. HADOOP-356.  Add contrib to "compile" and "test" build targets, so
    that this code is better maintained. (Michel Tourn via cutting)

13. HADOOP-307.  Add smallJobsBenchmark contrib module.  This runs
    lots of small jobs, in order to determine per-task overheads.
    (Sanjay Dahiya via cutting)

14. HADOOP-342.  Add a tool for log analysis: Logalyzer.
    (Arun C Murthy via cutting)

15. HADOOP-347.  Add web-based browsing of DFS content.  The namenode
    redirects browsing requests to datanodes.  Content requests are
    redirected to datanodes where the data is local when possible.
    (Devaraj Das via cutting)

16. HADOOP-351.  Make Hadoop IPC kernel independent of Jetty.
    (Devaraj Das via cutting)

17. HADOOP-237.  Add metric reporting to DFS and MapReduce.  With only
    minor configuration changes, one can now monitor many Hadoop
    system statistics using Ganglia or other monitoring systems.
    (Milind Bhandarkar via cutting)

18. HADOOP-376.  Fix datanode's HTTP server to scan for a free port.
    (omalley via cutting)

19. HADOOP-260.  Add --config option to shell scripts, specifying an
    alternate configuration directory. (Milind Bhandarkar via cutting)

20. HADOOP-381.  Permit developers to save the temporary files for
    tasks whose names match a regular expression, to facilliate
    debugging.  (omalley via cutting)

21. HADOOP-344.  Fix some Windows-related problems with DF.
    (Konstantin Shvachko via cutting)

22. HADOOP-380.  Fix reduce tasks to poll less frequently for map
    outputs. (Mahadev Konar via cutting)

23. HADOOP-321.  Refactor DatanodeInfo, in preparation for
    HADOOP-306.  (Konstantin Shvachko & omalley via cutting)

24. HADOOP-385.  Fix some bugs in record io code generation.
    (Milind Bhandarkar via cutting)

25. HADOOP-302.  Add new Text class to replace UTF8, removing
    limitations of that class.  Also refactor utility methods for
    writing zero-compressed integers (VInts and VLongs).
    (Hairong Kuang via cutting)

26. HADOOP-335.  Refactor DFS namespace/transaction logging in
    namenode.   (Konstantin Shvachko via cutting)

27. HADOOP-375.  Fix handling of the datanode HTTP daemon's port so
    that multiple datanode's can be run on a single host.
    (Devaraj Das via cutting)

28. HADOOP-386.  When removing excess DFS block replicas, remove those
    on nodes with the least free space first.
    (Johan Oskarson via cutting)

29. HADOOP-389.  Fix intermittent failures of mapreduce unit tests.
    Also fix some build dependencies.
    (Mahadev & Konstantin via cutting)

30. HADOOP-362.  Fix a problem where jobs hang when status messages
    are recieved out-of-order.  (omalley via cutting)

31. HADOOP-394.  Change order of DFS shutdown in unit tests to
    minimize errors logged.  (Konstantin Shvachko via cutting)

32. HADOOP-396.  Make DatanodeID implement Writable.
    (Konstantin Shvachko via cutting)

33. HADOOP-377.  Permit one to add URL resources to a Configuration.
    (Jean-Baptiste Quenot via cutting)

34. HADOOP-345.  Permit iteration over Configuration key/value pairs.
    (Michel Tourn via cutting)

35. HADOOP-409.  Streaming contrib module: make configuration
    properties available to commands as environment variables.
    (Michel Tourn via cutting)

36. HADOOP-369.  Add -getmerge option to dfs command that appends all
    files in a directory into a single local file.
    (Johan Oskarson via cutting)

37. HADOOP-410.  Replace some TreeMaps with HashMaps in DFS, for
    a 17% performance improvement. (Milind Bhandarkar via cutting)

38. HADOOP-411.  Add unit tests for command line parser.
    (Hairong Kuang via cutting)

39. HADOOP-412.  Add MapReduce input formats that support filtering
    of SequenceFile data, including sampling and regex matching.
    Also, move JobConf.newInstance() to a new utility class.
    (Hairong Kuang via cutting)

40. HADOOP-226.  Fix fsck command to properly consider replication
    counts, now that these can vary per file.  (Bryan Pendleton via cutting)

41. HADOOP-425.  Add a Python MapReduce example, using Jython.
    (omalley via cutting)


Release 0.4.0 - 2006-06-28

 1. HADOOP-298.  Improved progress reports for CopyFiles utility, the
    distributed file copier.  (omalley via cutting)

 2. HADOOP-299.  Fix the task tracker, permitting multiple jobs to
    more easily execute at the same time.  (omalley via cutting)

 3. HADOOP-250.  Add an HTTP user interface to the namenode, running
    on port 50070. (Devaraj Das via cutting)

 4. HADOOP-123.  Add MapReduce unit tests that run a jobtracker and
    tasktracker, greatly increasing code coverage.
    (Milind Bhandarkar via cutting)

 5. HADOOP-271.  Add links from jobtracker's web ui to tasktracker's
    web ui.  Also attempt to log a thread dump of child processes
    before they're killed.  (omalley via cutting)

 6. HADOOP-210.  Change RPC server to use a selector instead of a
    thread per connection.  This should make it easier to scale to
    larger clusters.  Note that this incompatibly changes the RPC
    protocol: clients and servers must both be upgraded to the new
    version to ensure correct operation.  (Devaraj Das via cutting)

 7. HADOOP-311.  Change DFS client to retry failed reads, so that a
    single read failure will not alone cause failure of a task.
    (omalley via cutting)

 8. HADOOP-314.  Remove the "append" phase when reducing.  Map output
    files are now directly passed to the sorter, without first
    appending them into a single file.  Now, the first third of reduce
    progress is "copy" (transferring map output to reduce nodes), the
    middle third is "sort" (sorting map output) and the last third is
    "reduce" (generating output).  Long-term, the "sort" phase will
    also be removed.  (omalley via cutting)

 9. HADOOP-316.  Fix a potential deadlock in the jobtracker.
    (omalley via cutting)

10. HADOOP-319.  Fix FileSystem.close() to remove the FileSystem
    instance from the cache.  (Hairong Kuang via cutting)

11. HADOOP-135.  Fix potential deadlock in JobTracker by acquiring
    locks in a consistent order.  (omalley via cutting)

12. HADOOP-278.  Check for existence of input directories before
    starting MapReduce jobs, making it easier to debug this common
    error.  (omalley via cutting)

13. HADOOP-304.  Improve error message for
    UnregisterdDatanodeException to include expected node name.
   (Konstantin Shvachko via cutting)

14. HADOOP-305.  Fix TaskTracker to ask for new tasks as soon as a
    task is finished, rather than waiting for the next heartbeat.
    This improves performance when tasks are short.
    (Mahadev Konar via cutting)

15. HADOOP-59.  Add support for generic command line options.  One may
    now specify the filesystem (-fs), the MapReduce jobtracker (-jt),
    a config file (-conf) or any configuration property (-D).  The
    "dfs", "fsck", "job", and "distcp" commands currently support
    this, with more to be added.  (Hairong Kuang via cutting)

16. HADOOP-296.  Permit specification of the amount of reserved space
    on a DFS datanode.  One may specify both the percentage free and
    the number of bytes.  (Johan Oskarson via cutting)

17. HADOOP-325.  Fix a problem initializing RPC parameter classes, and
    remove the workaround used to initialize classes.
    (omalley via cutting)

18. HADOOP-328.  Add an option to the "distcp" command to ignore read
    errors while copying.  (omalley via cutting)

19. HADOOP-27.  Don't allocate tasks to trackers whose local free
    space is too low.  (Johan Oskarson via cutting)

20. HADOOP-318.  Keep slow DFS output from causing task timeouts.
    This incompatibly changes some public interfaces, adding a
    parameter to OutputFormat.getRecordWriter() and the new method
    Reporter.progress(), but it makes lots of tasks succeed that were
    previously failing.  (Milind Bhandarkar via cutting)


Release 0.3.2 - 2006-06-09

 1. HADOOP-275.  Update the streaming contrib module to use log4j for
    its logging.  (Michel Tourn via cutting)

 2. HADOOP-279.  Provide defaults for log4j logging parameters, so
    that things still work reasonably when Hadoop-specific system
    properties are not provided.  (omalley via cutting)

 3. HADOOP-280.  Fix a typo in AllTestDriver which caused the wrong
    test to be run when "DistributedFSCheck" was specified.
   (Konstantin Shvachko via cutting)

 4. HADOOP-240.  DFS's mkdirs() implementation no longer logs a warning
    when the directory already exists. (Hairong Kuang via cutting)

 5. HADOOP-285.  Fix DFS datanodes to be able to re-join the cluster
    after the connection to the namenode is lost.  (omalley via cutting)

 6. HADOOP-277.  Fix a race condition when creating directories.
   (Sameer Paranjpye via cutting)

 7. HADOOP-289.  Improved exception handling in DFS datanode.
    (Konstantin Shvachko via cutting)

 8. HADOOP-292.  Fix client-side logging to go to standard error
    rather than standard output, so that it can be distinguished from
    application output.  (omalley via cutting)

 9. HADOOP-294.  Fixed bug where conditions for retrying after errors
    in the DFS client were reversed.  (omalley via cutting)


Release 0.3.1 - 2006-06-05

 1. HADOOP-272.  Fix a bug in bin/hadoop setting log
    parameters. (omalley & cutting)

 2. HADOOP-274.  Change applications to log to standard output rather
    than to a rolling log file like daemons.  (omalley via cutting)

 3. HADOOP-262.  Fix reduce tasks to report progress while they're
    waiting for map outputs, so that they do not time out.
    (Mahadev Konar via cutting)

 4. HADOOP-245 and HADOOP-246.  Improvements to record io package.  
    (Mahadev Konar via cutting)

 5. HADOOP-276.  Add logging config files to jar file so that they're
    always found.  (omalley via cutting)


Release 0.3.0 - 2006-06-02

 1. HADOOP-208.  Enhance MapReduce web interface, adding new pages
    for failed tasks, and tasktrackers.  (omalley via cutting)

 2. HADOOP-204.  Tweaks to metrics package.  (David Bowen via cutting)

 3. HADOOP-209.  Add a MapReduce-based file copier.  This will
    copy files within or between file systems in parallel.
    (Milind Bhandarkar via cutting)

 4. HADOOP-146.  Fix DFS to check when randomly generating a new block
    id that no existing blocks already have that id.
    (Milind Bhandarkar via cutting)

 5. HADOOP-180. Make a daemon thread that does the actual task clean ups, so
    that the main offerService thread in the taskTracker doesn't get stuck
    and miss his heartbeat window. This was killing many task trackers as
    big jobs finished (300+ tasks / node). (omalley via cutting)

 6. HADOOP-200. Avoid transmitting entire list of map task names to
    reduce tasks.  Instead just transmit the number of map tasks and
    henceforth refer to them by number when collecting map output.
    (omalley via cutting)

 7. HADOOP-219. Fix a NullPointerException when handling a checksum
    exception under SequenceFile.Sorter.sort().  (cutting & stack)

 8. HADOOP-212. Permit alteration of the file block size in DFS.  The
    default block size for new files may now be specified in the
    configuration with the dfs.block.size property.  The block size
    may also be specified when files are opened.
    (omalley via cutting)

 9. HADOOP-218. Avoid accessing configuration while looping through
    tasks in JobTracker.  (Mahadev Konar via cutting)

10. HADOOP-161. Add hashCode() method to DFS's Block.
    (Milind Bhandarkar via cutting)

11. HADOOP-115. Map output types may now be specified.  These are also
    used as reduce input types, thus permitting reduce input types to
    differ from reduce output types.  (Runping Qi via cutting)

12. HADOOP-216. Add task progress to task status page.
    (Bryan Pendelton via cutting)

13. HADOOP-233.  Add web server to task tracker that shows running
    tasks and logs.  Also add log access to job tracker web interface.
    (omalley via cutting)

14. HADOOP-205.  Incorporate pending tasks into tasktracker load
    calculations.  (Mahadev Konar via cutting)

15. HADOOP-247.  Fix sort progress to better handle exceptions.
    (Mahadev Konar via cutting)

16. HADOOP-195.  Improve performance of the transfer of map outputs to
    reduce nodes by performing multiple transfers in parallel, each on
    a separate socket.  (Sameer Paranjpye via cutting)

17. HADOOP-251.  Fix task processes to be tolerant of failed progress
    reports to their parent process.  (omalley via cutting)

18. HADOOP-325.  Improve the FileNotFound exceptions thrown by
    LocalFileSystem to include the name of the file.
    (Benjamin Reed via cutting)

19. HADOOP-254.  Use HTTP to transfer map output data to reduce
    nodes.  This, together with HADOOP-195, greatly improves the
    performance of these transfers.  (omalley via cutting)

20. HADOOP-163.  Cause datanodes that\ are unable to either read or
    write data to exit, so that the namenode will no longer target
    them for new blocks and will replicate their data on other nodes.
    (Hairong Kuang via cutting)

21. HADOOP-222.  Add a -setrep option to the dfs commands that alters
    file replication levels.  (Johan Oskarson via cutting)

22. HADOOP-75.  In DFS, only check for a complete file when the file
    is closed, rather than as each block is written.
    (Milind Bhandarkar via cutting)

23. HADOOP-124. Change DFS so that datanodes are identified by a
    persistent ID rather than by host and port.  This solves a number
    of filesystem integrity problems, when, e.g., datanodes are
    restarted.  (Konstantin Shvachko via cutting)

24. HADOOP-256.  Add a C API for DFS.  (Arun C Murthy via cutting)

25. HADOOP-211.  Switch to use the Jakarta Commons logging internally,
    configured to use log4j by default.  (Arun C Murthy and cutting)

26. HADOOP-265.  Tasktracker now fails to start if it does not have a
    writable local directory for temporary files.  In this case, it
    logs a message to the JobTracker and exits. (Hairong Kuang via cutting)

27. HADOOP-270.  Fix potential deadlock in datanode shutdown.
    (Hairong Kuang via cutting)

Release 0.2.1 - 2006-05-12

 1. HADOOP-199.  Fix reduce progress (broken by HADOOP-182).
    (omalley via cutting)

 2. HADOOP-201.  Fix 'bin/hadoop dfs -report'.  (cutting)

 3. HADOOP-207.  Fix JDK 1.4 incompatibility introduced by HADOOP-96.
    System.getenv() does not work in JDK 1.4.  (Hairong Kuang via cutting)


Release 0.2.0 - 2006-05-05

 1. Fix HADOOP-126. 'bin/hadoop dfs -cp' now correctly copies .crc
    files.  (Konstantin Shvachko via cutting)

 2. Fix HADOOP-51. Change DFS to support per-file replication counts.
    (Konstantin Shvachko via cutting)

 3. Fix HADOOP-131.  Add scripts to start/stop dfs and mapred daemons.
    Use these in start/stop-all scripts.  (Chris Mattmann via cutting)

 4. Stop using ssh options by default that are not yet in widely used
    versions of ssh.  Folks can still enable their use by uncommenting
    a line in conf/hadoop-env.sh. (cutting)

 5. Fix HADOOP-92.  Show information about all attempts to run each
    task in the web ui.  (Mahadev konar via cutting)

 6. Fix HADOOP-128.  Improved DFS error handling. (Owen O'Malley via cutting)

 7. Fix HADOOP-129.  Replace uses of java.io.File with new class named
    Path.  This fixes bugs where java.io.File methods were called
    directly when FileSystem methods were desired, and reduces the
    likelihood of such bugs in the future.  It also makes the handling
    of pathnames more consistent between local and dfs FileSystems and
    between Windows and Unix. java.io.File-based methods are still
    available for back-compatibility, but are deprecated and will be
    removed once 0.2 is released. (cutting)

 8. Change dfs.data.dir and mapred.local.dir to be comma-separated
    lists of directories, no longer be space-separated. This fixes
    several bugs on Windows. (cutting)

 9. Fix HADOOP-144.  Use mapred task id for dfs client id, to
    facilitate debugging.  (omalley via cutting)

10. Fix HADOOP-143.  Do not line-wrap stack-traces in web ui.
    (omalley via cutting)

11. Fix HADOOP-118.  In DFS, improve clean up of abandoned file
    creations.  (omalley via cutting)

12. Fix HADOOP-138.  Stop multiple tasks in a single heartbeat, rather
    than one per heartbeat.  (Stefan via cutting)

13. Fix HADOOP-139.  Remove a potential deadlock in
    LocalFileSystem.lock().  (Igor Bolotin via cutting)

14. Fix HADOOP-134.  Don't hang jobs when the tasktracker is
    misconfigured to use an un-writable local directory.  (omalley via cutting)

15. Fix HADOOP-115.  Correct an error message.  (Stack via cutting)

16. Fix HADOOP-133.  Retry pings from child to parent, in case of
    (local) communcation problems.  Also log exit status, so that one
    can distinguish patricide from other deaths.  (omalley via cutting)

17. Fix HADOOP-142.  Avoid re-running a task on a host where it has
    previously failed.  (omalley via cutting)

18. Fix HADOOP-148.  Maintain a task failure count for each
    tasktracker and display it in the web ui.  (omalley via cutting)

19. Fix HADOOP-151.  Close a potential socket leak, where new IPC
    connection pools were created per configuration instance that RPCs
    use.  Now a global RPC connection pool is used again, as
    originally intended.  (cutting)

20. Fix HADOOP-69.  Don't throw a NullPointerException when getting
    hints for non-existing file split.  (Bryan Pendelton via cutting)

21. Fix HADOOP-157.  When a task that writes dfs files (e.g., a reduce
    task) failed and was retried, it would fail again and again,
    eventually failing the job.  The problem was that dfs did not yet
    know that the failed task had abandoned the files, and would not
    yet let another task create files with the same names.  Dfs now
    retries when creating a file long enough for locks on abandoned
    files to expire.  (omalley via cutting)

22. Fix HADOOP-150.  Improved task names that include job
    names. (omalley via cutting)

23. Fix HADOOP-162.  Fix ConcurrentModificationException when
    releasing file locks. (omalley via cutting)

24. Fix HADOOP-132.  Initial check-in of new Metrics API, including 
    implementations for writing metric data to a file and for sending
    it to Ganglia.  (David Bowen via cutting)

25. Fix HADOOP-160.  Remove some uneeded synchronization around
    time-consuming operations in the TaskTracker.  (omalley via cutting)

26. Fix HADOOP-166.  RPCs failed when passed subclasses of a declared
    parameter type.  This is fixed by changing ObjectWritable to store
    both the declared type and the instance type for Writables.  Note
    that this incompatibly changes the format of ObjectWritable and
    will render unreadable any ObjectWritables stored in files.
    Nutch only uses ObjectWritable in intermediate files, so this
    should not be a problem for Nutch.  (Stefan & cutting)

27. Fix HADOOP-168.  MapReduce RPC protocol methods should all declare
    IOException, so that timeouts are handled appropriately.
    (omalley via cutting)

28. Fix HADOOP-169.  Don't fail a reduce task if a call to the
    jobtracker to locate map outputs fails.  (omalley via cutting)

29. Fix HADOOP-170.  Permit FileSystem clients to examine and modify
    the replication count of individual files.  Also fix a few
    replication-related bugs. (Konstantin Shvachko via cutting)

30. Permit specification of a higher replication levels for job
    submission files (job.xml and job.jar).  This helps with large
    clusters, since these files are read by every node.  (cutting)

31. HADOOP-173.  Optimize allocation of tasks with local data.  (cutting)

32. HADOOP-167.  Reduce number of Configurations and JobConf's
    created.  (omalley via cutting)

33. NUTCH-256.  Change FileSystem#createNewFile() to create a .crc
    file.  The lack of a .crc file was causing warnings.  (cutting)

34. HADOOP-174.  Change JobClient to not abort job until it has failed
    to contact the job tracker for five attempts, not just one as
    before.  (omalley via cutting)

35. HADOOP-177.  Change MapReduce web interface to page through tasks.
    Previously, when jobs had more than a few thousand tasks they
    could crash web browsers.  (Mahadev Konar via cutting)

36. HADOOP-178.  In DFS, piggyback blockwork requests from datanodes
    on heartbeat responses from namenode.  This reduces the volume of
    RPC traffic.  Also move startup delay in blockwork from datanode
    to namenode.  This fixes a problem where restarting the namenode
    triggered a lot of uneeded replication. (Hairong Kuang via cutting)

37. HADOOP-183.  If the DFS namenode is restarted with different
    minimum and/or maximum replication counts, existing files'
    replication counts are now automatically adjusted to be within the
    newly configured bounds. (Hairong Kuang via cutting)

38. HADOOP-186.  Better error handling in TaskTracker's top-level
    loop.  Also improve calculation of time to send next heartbeat.
    (omalley via cutting)

39. HADOOP-187.  Add two MapReduce examples/benchmarks.  One creates
    files containing random data.  The second sorts the output of the
    first.  (omalley via cutting)

40. HADOOP-185.  Fix so that, when a task tracker times out making the
    RPC asking for a new task to run, the job tracker does not think
    that it is actually running the task returned.  (omalley via cutting)

41. HADOOP-190.  If a child process hangs after it has reported
    completion, its output should not be lost.  (Stack via cutting)

42. HADOOP-184. Re-structure some test code to better support testing
    on a cluster.  (Mahadev Konar via cutting)

43. HADOOP-191  Add streaming package, Hadoop's first contrib module.
    This permits folks to easily submit MapReduce jobs whose map and
    reduce functions are implemented by shell commands.  Use
    'bin/hadoop jar build/hadoop-streaming.jar' to get details.
    (Michel Tourn via cutting)

44. HADOOP-189.  Fix MapReduce in standalone configuration to
    correctly handle job jar files that contain a lib directory with
    nested jar files.  (cutting)

45. HADOOP-65.  Initial version of record I/O framework that enables
    the specification of record types and generates marshalling code
    in both Java and C++.  Generated Java code implements
    WritableComparable, but is not yet otherwise used by
    Hadoop. (Milind Bhandarkar via cutting)

46. HADOOP-193.  Add a MapReduce-based FileSystem benchmark.
    (Konstantin Shvachko via cutting)

47. HADOOP-194.  Add a MapReduce-based FileSystem checker.  This reads
    every block in every file in the filesystem.  (Konstantin Shvachko
    via cutting)

48. HADOOP-182.  Fix so that lost task trackers to not change the
    status of reduce tasks or completed jobs.  Also fixes the progress
    meter so that failed tasks are subtracted. (omalley via cutting)

49. HADOOP-96.  Logging improvements.  Log files are now separate from
    standard output and standard error files.  Logs are now rolled.
    Logging of all DFS state changes can be enabled, to facilitate
    debugging.  (Hairong Kuang via cutting)


Release 0.1.1 - 2006-04-08

 1. Added CHANGES.txt, logging all significant changes to Hadoop.  (cutting)

 2. Fix MapReduceBase.close() to throw IOException, as declared in the
    Closeable interface.  This permits subclasses which override this
    method to throw that exception. (cutting)

 3. Fix HADOOP-117.  Pathnames were mistakenly transposed in
    JobConf.getLocalFile() causing many mapred temporary files to not
    be removed.  (Raghavendra Prabhu via cutting)
 
 4. Fix HADOOP-116. Clean up job submission files when jobs complete.
    (cutting)

 5. Fix HADOOP-125. Fix handling of absolute paths on Windows (cutting)

Release 0.1.0 - 2006-04-01

 1. The first release of Hadoop.