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From jbel...@apache.org
Subject [1/3] git commit: Fix EstimatedHistogram races patch by Paulo Gaspar; reviewed by jbellis for CASSANDRA-6682
Date Mon, 10 Feb 2014 06:43:33 GMT
Updated Branches:
  refs/heads/cassandra-2.0 800e45f48 -> 16f99c5a2
  refs/heads/trunk 319877fda -> de9be79d5


Fix EstimatedHistogram races
patch by Paulo Gaspar; reviewed by jbellis for CASSANDRA-6682


Project: http://git-wip-us.apache.org/repos/asf/cassandra/repo
Commit: http://git-wip-us.apache.org/repos/asf/cassandra/commit/16f99c5a
Tree: http://git-wip-us.apache.org/repos/asf/cassandra/tree/16f99c5a
Diff: http://git-wip-us.apache.org/repos/asf/cassandra/diff/16f99c5a

Branch: refs/heads/cassandra-2.0
Commit: 16f99c5a2edd2df3ed9512d3598d60f845e58d19
Parents: 800e45f
Author: Jonathan Ellis <jbellis@apache.org>
Authored: Mon Feb 10 00:43:14 2014 -0600
Committer: Jonathan Ellis <jbellis@apache.org>
Committed: Mon Feb 10 00:43:14 2014 -0600

----------------------------------------------------------------------
 CHANGES.txt                                     |  2 ++
 .../cassandra/utils/EstimatedHistogram.java     | 31 ++++++++++++--------
 2 files changed, 20 insertions(+), 13 deletions(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/cassandra/blob/16f99c5a/CHANGES.txt
----------------------------------------------------------------------
diff --git a/CHANGES.txt b/CHANGES.txt
index d32490e..b98dec7 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,4 +1,5 @@
 2.0.6
+ * Fix EstimatedHistogram races (CASSANDRA-6682)
  * Failure detector correctly converts initial value to nanos (CASSANDRA-6658)
  * Add nodetool taketoken to relocate vnodes (CASSANDRA-4445)
  * Fix upgradesstables NPE for non-CF-based indexes (CASSANDRA-6645)
@@ -13,6 +14,7 @@ Merged from 1.2:
  * Fix mean cells and mean row size per sstable calculations (CASSANDRA-6667)
  * Compact hints after partial replay to clean out tombstones (CASSANDRA-6666)
 
+
 2.0.5
  * Reduce garbage generated by bloom filter lookups (CASSANDRA-6609)
  * Add ks.cf names to tombstone logging (CASSANDRA-6597)

http://git-wip-us.apache.org/repos/asf/cassandra/blob/16f99c5a/src/java/org/apache/cassandra/utils/EstimatedHistogram.java
----------------------------------------------------------------------
diff --git a/src/java/org/apache/cassandra/utils/EstimatedHistogram.java b/src/java/org/apache/cassandra/utils/EstimatedHistogram.java
index 1b8ffe1..5941057 100644
--- a/src/java/org/apache/cassandra/utils/EstimatedHistogram.java
+++ b/src/java/org/apache/cassandra/utils/EstimatedHistogram.java
@@ -44,7 +44,7 @@ public class EstimatedHistogram
      *
      * Each bucket represents values from (previous bucket offset, current offset].
      */
-    private long[] bucketOffsets;
+    private final long[] bucketOffsets;
 
     // buckets is one element longer than bucketOffsets -- the last element is values greater
than the last offset
     final AtomicLongArray buckets;
@@ -56,7 +56,7 @@ public class EstimatedHistogram
 
     public EstimatedHistogram(int bucketCount)
     {
-        makeOffsets(bucketCount);
+        bucketOffsets = newOffsets(bucketCount);
         buckets = new AtomicLongArray(bucketOffsets.length + 1);
     }
 
@@ -67,19 +67,21 @@ public class EstimatedHistogram
         buckets = new AtomicLongArray(bucketData);
     }
 
-    private void makeOffsets(int size)
+    private static long[] newOffsets(int size)
     {
-        bucketOffsets = new long[size];
+        long[] result = new long[size];
         long last = 1;
-        bucketOffsets[0] = last;
+        result[0] = last;
         for (int i = 1; i < size; i++)
         {
             long next = Math.round(last * 1.2);
             if (next == last)
                 next++;
-            bucketOffsets[i] = next;
+            result[i] = next;
             last = next;
         }
+
+        return result;
     }
 
     /**
@@ -120,13 +122,15 @@ public class EstimatedHistogram
      */
     public long[] getBuckets(boolean reset)
     {
-        long[] rv = new long[buckets.length()];
-        for (int i = 0; i < buckets.length(); i++)
-            rv[i] = buckets.get(i);
+        final int len = buckets.length();
+        long[] rv = new long[len];
 
         if (reset)
-            for (int i = 0; i < buckets.length(); i++)
-                buckets.set(i, 0L);
+            for (int i = 0; i < len; i++)
+                rv[i] = buckets.getAndSet(i, 0L);
+        else
+            for (int i = 0; i < len; i++)
+                rv[i] = buckets.get(i);
 
         return rv;
     }
@@ -201,8 +205,9 @@ public class EstimatedHistogram
         long sum = 0;
         for (int i = 0; i < lastBucket; i++)
         {
-            elements += buckets.get(i);
-            sum += buckets.get(i) * bucketOffsets[i];
+            long bCount = buckets.get(i);
+            elements += bCount;
+            sum += bCount * bucketOffsets[i];
         }
 
         return (long) Math.ceil((double) sum / elements);


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