svn commit: r1181920 - /hbase/branches/0.89/src/test/java/org/apache/hadoop/hbase/loadtest/RegionSplitter.java

[ns...@apache.org]

Author: nspiegelberg
Date: Tue Oct 11 17:42:04 2011
New Revision: 1181920

URL: http://svn.apache.org/viewvc?rev=1181920&view=rev
Log:
HBase RegionSplitter: Split on low-loaded regions first

Summary:
Always split on low-loaded regions first.  This will prevent
the load balancing slop from kicking in during rolling splits.

Test Plan:  - bin/hbase RegionSplitter table -o 20
Reviewed By: kranganathan
Reviewers: kranganathan
CC: kranganathan
Differential Revision: 297100
Task ID: 510843

Modified:
    hbase/branches/0.89/src/test/java/org/apache/hadoop/hbase/loadtest/RegionSplitter.java

Modified: hbase/branches/0.89/src/test/java/org/apache/hadoop/hbase/loadtest/RegionSplitter.java
URL: http://svn.apache.org/viewvc/hbase/branches/0.89/src/test/java/org/apache/hadoop/hbase/loadtest/RegionSplitter.java?rev=1181920&r1=1181919&r2=1181920&view=diff
==============================================================================
--- hbase/branches/0.89/src/test/java/org/apache/hadoop/hbase/loadtest/RegionSplitter.java (original)
+++ hbase/branches/0.89/src/test/java/org/apache/hadoop/hbase/loadtest/RegionSplitter.java Tue Oct 11 17:42:04 2011
@@ -4,7 +4,11 @@ import java.io.IOException;
 import java.math.BigInteger;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
+import java.util.Collections;
+import java.util.Comparator;
 import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
 import java.util.Set;
 import java.util.TreeMap;
 
@@ -272,10 +276,29 @@ public class RegionSplitter {
       while (!daughterRegions.isEmpty()) {
         LOG.debug(daughterRegions.size() + " RS have regions to splt.");
 
-        // round-robin through the RS list
-        for (HServerAddress rsLoc = daughterRegions.firstKey();
-             rsLoc != null;
-             rsLoc = daughterRegions.higherKey(rsLoc)) {
+        // Get RegionServer : region count mapping
+        final TreeMap<HServerAddress, Integer> rsSizes = Maps.newTreeMap();
+        Map<HRegionInfo, HServerAddress> regionsInfo = table.getRegionsInfo();
+        for (HServerAddress rs : regionsInfo.values()) {
+          if (rsSizes.containsKey(rs)) {
+            rsSizes.put(rs, rsSizes.get(rs) + 1);
+          } else {
+            rsSizes.put(rs, 1);
+          }
+        }
+
+        // sort the RS by the number of regions they have
+        List<HServerAddress> serversLeft = Lists.newArrayList(daughterRegions
+            .keySet());
+        Collections.sort(serversLeft, new Comparator<HServerAddress>() {
+          public int compare(HServerAddress o1, HServerAddress o2) {
+            return rsSizes.get(o1).compareTo(rsSizes.get(o2));
+          }
+        });
+
+        // round-robin through the RS list. Choose the lightest-loaded servers
+        // first to keep the master from load-balancing regions as we split.
+        for (HServerAddress rsLoc : serversLeft) {
           Pair<BigInteger, BigInteger> dr = null;
 
           // find a region in the RS list that hasn't been moved