HDFS-8795. Improve InvalidateBlocks#node2blocks. (yliu)

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

@@ -397,6 +397,8 @@ Release 2.8.0 - UNRELEASED
     HDFS-8495. Consolidate append() related implementation into a single class.
     (Rakesh R via wheat9)
 
+    HDFS-8795. Improve InvalidateBlocks#node2blocks. (yliu)
+
   OPTIMIZATIONS
 
     HDFS-8026. Trace FSOutputSummer#writeChecksumChunks rather than

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

@@ -22,9 +22,9 @@ import java.text.SimpleDateFormat;
 import java.util.ArrayList;
 import java.util.Calendar;
 import java.util.GregorianCalendar;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
-import java.util.TreeMap;
 
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.hdfs.DFSConfigKeys;
@@ -36,6 +36,7 @@ import org.apache.hadoop.util.Time;
 import org.apache.hadoop.hdfs.DFSUtil;
 
 import com.google.common.annotations.VisibleForTesting;
+
 import org.slf4j.Logger;
 
 /**
@@ -47,7 +48,7 @@ import org.slf4j.Logger;
 class InvalidateBlocks {
   /** Mapping: DatanodeInfo -> Collection of Blocks */
   private final Map<DatanodeInfo, LightWeightHashSet<Block>> node2blocks =
-      new TreeMap<DatanodeInfo, LightWeightHashSet<Block>>();
+      new HashMap<DatanodeInfo, LightWeightHashSet<Block>>();
   /** The total number of blocks in the map. */
   private long numBlocks = 0L;