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From Maki Watanabe <watanabe.m...@gmail.com>
Subject nodetool cleanup promotes all sstable and may cause CASSANDRA-3608
Date Thu, 01 Mar 2012 16:08:23 GMT
Hello, I've faced same issue reported at:

https://issues.apache.org/jira/browse/CASSANDRA-3608
  nodetool cleanup fails on LeveledCompactionStrategy tables with
ArrayIndexOutOfBoundsException

in 1.0.7, and investigated the issue.
I think there are two problems in LeveledManifest.java.

1. "generations" is a fixed length list, but add(SSTableReader, int)
method doesn't check the boundary.
     So if Cassandra try to promote sstables in the highest
generation, it will cause ArrayIndexOutOfBoundsException.

2. promote method promotes all sstables during cleanup compaction.
    If you have only one sstable at L1, nodetool cleanup promotes it to L2.
    If you run cleanup 6 times, the sstable is promoted to L7.
    7th cleanup causes ArrayIndexOutOfBoundsException when you use
sstable_size_in_mb: 5.

I made a patch for the issue#2, because issue#1 will not happen until
the node will store
Peta Bytes of data with the issue#2 patch.

The patch is made against cassandra-1.0.7.
I'm not familiar with git. If I need to make the patch in other
format, please let me know.

maki


>From 47ab7dc007db4c1d4ff28786acea1c99cbf6e19e Mon Sep 17 00:00:00 2001
From: Maki Watanabe <watanabe.maki@gmail.com>
Date: Fri, 2 Mar 2012 00:28:30 +0900
Subject: [PATCH] Fix promote() not to promote files at cleanup compaction
 etc.

---
 .../cassandra/db/compaction/LeveledManifest.java   |   11 ++++++++++-
 1 files changed, 10 insertions(+), 1 deletions(-)

diff --git a/src/java/org/apache/cassandra/db/compaction/LeveledManifest.java
b/src/java/org/apache/cassandra/db/compaction/LeveledManifest.java
index 40a0a17..8eea2e3 100644
--- a/src/java/org/apache/cassandra/db/compaction/LeveledManifest.java
+++ b/src/java/org/apache/cassandra/db/compaction/LeveledManifest.java
@@ -163,19 +163,27 @@ public class LeveledManifest
         // plus one if the removed were all on the same level
         int minimumLevel = Integer.MAX_VALUE;
         int maximumLevel = 0;
+        int removedCount = 0;
         for (SSTableReader sstable : removed)
         {
             int thisLevel = levelOf(sstable);
             maximumLevel = Math.max(maximumLevel, thisLevel);
             minimumLevel = Math.min(minimumLevel, thisLevel);
             remove(sstable);
+            removedCount++;
         }

         // it's valid to do a remove w/o an add (e.g. on truncate)
         if (!added.iterator().hasNext())
             return;

-        int newLevel = minimumLevel == maximumLevel ? maximumLevel +
1 : maximumLevel;
+        int newLevel = 0;
+        if (removedCount == 1)
+        	// We don't want to promote sstable at cleanup compaction etc.
+        	newLevel = maximumLevel;
+        else
+        	newLevel = minimumLevel == maximumLevel ? maximumLevel + 1 :
maximumLevel;
+
         newLevel = skipLevels(newLevel, added);
         assert newLevel > 0;
         if (logger.isDebugEnabled())
@@ -295,6 +303,7 @@ public class LeveledManifest

     private void add(SSTableReader sstable, int level)
     {
+    	// If you promote highest generation, this will cause
ArrayIndexOutOfBoundsException (CASSANDRA-3608)
         generations[level].add(sstable);
     }

-- 
1.7.7.4

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