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https://issues.apache.org/jira/browse/HBASE-16440?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15433311#comment-15433311
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Hudson commented on HBASE-16440:
--------------------------------

FAILURE: Integrated in Jenkins build HBase-Trunk_matrix #1468 (See 
[https://builds.apache.org/job/HBase-Trunk_matrix/1468/])
HBASE-16440 MemstoreChunkPool might cross its maxCount of chunks to 
(anoopsamjohn: rev 897631f8d194911e0004b9c98d4040e9794bb2e9)
* (edit) 
hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestMemStoreChunkPool.java
* (add) 
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/Chunk.java
* (edit) 
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HeapMemStoreLAB.java
* (edit) 
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/MemStoreChunkPool.java


> MemstoreChunkPool might cross its maxCount of chunks to pool
> ------------------------------------------------------------
>
>                 Key: HBASE-16440
>                 URL: https://issues.apache.org/jira/browse/HBASE-16440
>             Project: HBase
>          Issue Type: Sub-task
>            Reporter: Anoop Sam John
>            Assignee: Anoop Sam John
>             Fix For: 2.0.0
>
>         Attachments: HBASE-16440.patch, HBASE-16440_V2.patch, 
> HBASE-16440_V3.patch, HBASE-16440_V4.patch
>
>
> {code}
> void putbackChunks(BlockingQueue<Chunk> chunks) {
>     int maxNumToPutback = this.maxCount - reclaimedChunks.size();
>     if (maxNumToPutback <= 0) {
>       return;
>     }
>     chunks.drainTo(reclaimedChunks, maxNumToPutback);
>     // clear reference of any non-reclaimable chunks
>     if (chunks.size() > 0) {
>       if (LOG.isTraceEnabled()) {
>         LOG.trace("Left " + chunks.size() + " unreclaimable chunks, removing 
> them from queue");
>       }
>       chunks.clear();
>     }
>   }
> {code}
> There is no synchroization. 2 threads might be calling this API as part of a 
> MSLAB close. (Once the memstore is flushed). It pass all the chunks used by 
> it.  (Those might  not have been come from pool also).  We try to put back 
> chunks such that it is not crossing maxCount.   Suppose maxCount is 10 and 
> currently no chunks in 'reclaimedChunks'. Say both threads at line one. Both 
> see 'maxNumToPutback ' as 10 and that will make 20 chunks being pooled.  
> Similar issue is in putbackChunk(Chunk chunk) API also.



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