HDFS-6085. Improve CacheReplicationMonitor log messages a bit (cmccabe)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1576194 13f79535-47bb-0310-9956-ffa450edef68

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -399,6 +399,8 @@ Release 2.4.0 - UNRELEASED
     HDFS-3405. Checkpointing should use HTTP POST or PUT instead of GET-GET
     to send merged fsimages. (Vinayakumar B via wang)
 
+    HDFS-6085. Improve CacheReplicationMonitor log messages a bit (cmccabe)
+
   OPTIMIZATIONS
 
     HDFS-5790. LeaseManager.findPath is very slow when many leases need recovery

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/CacheReplicationMonitor.java

@@ -313,30 +313,32 @@ public class CacheReplicationMonitor extends Thread implements Closeable {
     FSDirectory fsDir = namesystem.getFSDirectory();
     final long now = new Date().getTime();
     for (CacheDirective directive : cacheManager.getCacheDirectives()) {
+      scannedDirectives++;
       // Skip processing this entry if it has expired
-      if (LOG.isTraceEnabled()) {
-        LOG.trace("Directive expiry is at " + directive.getExpiryTime());
-      }
       if (directive.getExpiryTime() > 0 && directive.getExpiryTime() <= now) {
         if (LOG.isDebugEnabled()) {
-          LOG.debug("Skipping directive id " + directive.getId()
-              + " because it has expired (" + directive.getExpiryTime() + "<="
-              + now + ")");
+          LOG.debug("Directive " + directive.getId() + ": the directive " +
+              "expired at " + directive.getExpiryTime() + " (now = " +
+              now + ")");
         }
         continue;
       }
-      scannedDirectives++;
       String path = directive.getPath();
       INode node;
       try {
         node = fsDir.getINode(path);
       } catch (UnresolvedLinkException e) {
         // We don't cache through symlinks
+        if (LOG.isDebugEnabled()) {
+          LOG.debug("Directive " + directive.getId() +
+              ": got UnresolvedLinkException while resolving path " + path);
+        }
         continue;
       }
       if (node == null)  {
         if (LOG.isDebugEnabled()) {
-          LOG.debug("No inode found at " + path);
+          LOG.debug("Directive " + directive.getId() +
+              ": No inode found at " + path);
         }
       } else if (node.isDirectory()) {
         INodeDirectory dir = node.asDirectory();
@@ -351,8 +353,8 @@ public class CacheReplicationMonitor extends Thread implements Closeable {
         rescanFile(directive, node.asFile());
       } else {
         if (LOG.isDebugEnabled()) {
-          LOG.debug("Ignoring non-directory, non-file inode " + node +
-                    " found at " + path);
+          LOG.debug("Directive " + directive.getId() + 
+              ": ignoring non-directive, non-file inode " + node);
         }
       }
     }
@@ -380,8 +382,8 @@ public class CacheReplicationMonitor extends Thread implements Closeable {
     CachePool pool = directive.getPool();
     if (pool.getBytesNeeded() > pool.getLimit()) {
       if (LOG.isDebugEnabled()) {
-        LOG.debug(String.format("Skipping directive id %d file %s because "
-            + "limit of pool %s would be exceeded (%d > %d)",
+        LOG.debug(String.format("Directive %d: not scanning file %s because " +
+            "bytesNeeded for pool %s is %d, but the pool's limit is %d",
             directive.getId(),
             file.getFullPathName(),
             pool.getPoolName(),
@@ -395,6 +397,11 @@ public class CacheReplicationMonitor extends Thread implements Closeable {
     for (BlockInfo blockInfo : blockInfos) {
       if (!blockInfo.getBlockUCState().equals(BlockUCState.COMPLETE)) {
         // We don't try to cache blocks that are under construction.
+        if (LOG.isTraceEnabled()) {
+          LOG.trace("Directive " + directive.getId() + ": can't cache " +
+              "block " + blockInfo + " because it is in state " +
+              blockInfo.getBlockUCState() + ", not COMPLETE.");
+        }
         continue;
       }
       Block block = new Block(blockInfo.getBlockId());
@@ -403,6 +410,7 @@ public class CacheReplicationMonitor extends Thread implements Closeable {
       CachedBlock ocblock = cachedBlocks.get(ncblock);
       if (ocblock == null) {
         cachedBlocks.put(ncblock);
+        ocblock = ncblock;
       } else {
         // Update bytesUsed using the current replication levels.
         // Assumptions: we assume that all the blocks are the same length
@@ -433,14 +441,18 @@ public class CacheReplicationMonitor extends Thread implements Closeable {
           ocblock.setReplicationAndMark(directive.getReplication(), mark);
         }
       }
+      if (LOG.isTraceEnabled()) {
+        LOG.trace("Directive " + directive.getId() + ": setting replication " +
+                "for block " + blockInfo + " to " + ocblock.getReplication());
+      }
     }
     // Increment the "cached" statistics
     directive.addBytesCached(cachedTotal);
     if (cachedTotal == neededTotal) {
       directive.addFilesCached(1);
     }
-    if (LOG.isTraceEnabled()) {
-      LOG.trace("Directive " + directive.getId() + " is caching " +
+    if (LOG.isDebugEnabled()) {
+      LOG.debug("Directive " + directive.getId() + ": caching " +
           file.getFullPathName() + ": " + cachedTotal + "/" + neededTotal +
           " bytes");
     }
@@ -500,6 +512,11 @@ public class CacheReplicationMonitor extends Thread implements Closeable {
           iter.hasNext(); ) {
         DatanodeDescriptor datanode = iter.next();
         if (!cblock.isInList(datanode.getCached())) {
+          if (LOG.isTraceEnabled()) {
+            LOG.trace("Block " + cblock.getBlockId() + ": removing from " +
+                "PENDING_UNCACHED for node " + datanode.getDatanodeUuid() +
+                "because the DataNode uncached it.");
+          }
           datanode.getPendingUncached().remove(cblock);
           iter.remove();
         }
@@ -509,8 +526,9 @@ public class CacheReplicationMonitor extends Thread implements Closeable {
       String reason = findReasonForNotCaching(cblock, blockInfo);
       int neededCached = 0;
       if (reason != null) {
-        if (LOG.isDebugEnabled()) {
-          LOG.debug("not caching " + cblock + " because it is " + reason);
+        if (LOG.isTraceEnabled()) {
+          LOG.trace("Block " + cblock.getBlockId() + ": can't cache " +
+              "block because it is " + reason);
         }
       } else {
         neededCached = cblock.getReplication();
@@ -523,6 +541,12 @@ public class CacheReplicationMonitor extends Thread implements Closeable {
           DatanodeDescriptor datanode = iter.next();
           datanode.getPendingCached().remove(cblock);
           iter.remove();
+          if (LOG.isTraceEnabled()) {
+            LOG.trace("Block " + cblock.getBlockId() + ": removing from " +
+                "PENDING_CACHED for node " + datanode.getDatanodeUuid() +
+                "because we already have " + numCached + " cached " +
+                "replicas and we only need " + neededCached);
+          }
         }
       }
       if (numCached < neededCached) {
@@ -532,6 +556,12 @@ public class CacheReplicationMonitor extends Thread implements Closeable {
           DatanodeDescriptor datanode = iter.next();
           datanode.getPendingUncached().remove(cblock);
           iter.remove();
+          if (LOG.isTraceEnabled()) {
+            LOG.trace("Block " + cblock.getBlockId() + ": removing from " +
+                "PENDING_UNCACHED for node " + datanode.getDatanodeUuid() +
+                "because we only have " + numCached + " cached replicas " +
+                "and we need " + neededCached);
+          }
         }
       }
       int neededUncached = numCached -
@@ -551,6 +581,11 @@ public class CacheReplicationMonitor extends Thread implements Closeable {
           pendingUncached.isEmpty() &&
           pendingCached.isEmpty()) {
         // we have nothing more to do with this block.
+        if (LOG.isTraceEnabled()) {
+          LOG.trace("Block " + cblock.getBlockId() + ": removing from " +
+              "cachedBlocks, since neededCached == 0, and " +
+              "pendingUncached and pendingCached are empty.");
+        }
         cbIter.remove();
       }
     }
@@ -609,15 +644,16 @@ public class CacheReplicationMonitor extends Thread implements Closeable {
           getStoredBlock(new Block(cachedBlock.getBlockId()));
     if (blockInfo == null) {
       if (LOG.isDebugEnabled()) {
-        LOG.debug("Not caching block " + cachedBlock + " because there " +
-            "is no record of it on the NameNode.");
+        LOG.debug("Block " + cachedBlock.getBlockId() + ": can't add new " +
+            "cached replicas, because there is no record of this block " +
+            "on the NameNode.");
       }
       return;
     }
     if (!blockInfo.isComplete()) {
       if (LOG.isDebugEnabled()) {
-        LOG.debug("Not caching block " + cachedBlock + " because it " +
-            "is not yet complete.");
+        LOG.debug("Block " + cachedBlock.getBlockId() + ": can't cache this " +
+            "block, because it is not yet complete.");
       }
       return;
     }
@@ -665,10 +701,11 @@ public class CacheReplicationMonitor extends Thread implements Closeable {
       }
       if (pendingCapacity < blockInfo.getNumBytes()) {
         if (LOG.isTraceEnabled()) {
-          LOG.trace("Datanode " + datanode + " is not a valid possibility for"
-              + " block " + blockInfo.getBlockId() + " of size "
-              + blockInfo.getNumBytes() + " bytes, only has "
-              + datanode.getCacheRemaining() + " bytes of cache remaining.");
+          LOG.trace("Block " + blockInfo.getBlockId() + ": DataNode " +
+              datanode.getDatanodeUuid() + " is not a valid possibility " +
+              "because the block has size " + blockInfo.getNumBytes() + ", but " +
+              "the DataNode only has " + datanode.getCacheRemaining() + " " +
+              "bytes of cache remaining.");
         }
         outOfCapacity++;
         continue;
@@ -678,6 +715,10 @@ public class CacheReplicationMonitor extends Thread implements Closeable {
     List<DatanodeDescriptor> chosen = chooseDatanodesForCaching(possibilities,
         neededCached, blockManager.getDatanodeManager().getStaleInterval());
     for (DatanodeDescriptor datanode : chosen) {
+      if (LOG.isTraceEnabled()) {
+          LOG.trace("Block " + blockInfo.getBlockId() + ": added to " +
+              "PENDING_CACHED on DataNode " + datanode.getDatanodeUuid());
+      }
       pendingCached.add(datanode);
       boolean added = datanode.getPendingCached().add(cachedBlock);
       assert added;
@@ -685,12 +726,10 @@ public class CacheReplicationMonitor extends Thread implements Closeable {
     // We were unable to satisfy the requested replication factor
     if (neededCached > chosen.size()) {
       if (LOG.isDebugEnabled()) {
-        LOG.debug(
-            "Only have " +
+        LOG.debug("Block " + blockInfo.getBlockId() + ": we only have " +
             (cachedBlock.getReplication() - neededCached + chosen.size()) +
-            " of " + cachedBlock.getReplication() + " cached replicas for " +
-            cachedBlock + " (" + outOfCapacity + " nodes have insufficient " +
-            "capacity).");
+            " of " + cachedBlock.getReplication() + " cached replicas.  " +
+            outOfCapacity + " DataNodes have insufficient cache capacity.");
       }
     }
   }