hbase-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Enis Soztutar (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-8143) HBase on Hadoop 2 with local short circuit reads (ssr) causes OOM
Date Tue, 19 Mar 2013 06:21:16 GMT

    [ https://issues.apache.org/jira/browse/HBASE-8143?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13606109#comment-13606109

Enis Soztutar commented on HBASE-8143:

bq. if you did not set MaxDirectMemorySize option explicitly, then it will be equal to -Xmx,
that means -XX:MaxDirectMemorySize == -Xmx == 3g for Enis's case.
In this case, I was not even aware of Hdfs 2 allocating direct memory. I did not spend a lot
of time on the hadoop 2 code base.
bq. In BlockReaderLocal the short circuit buffer size is configurable with "dfs.client.read.shortcircuit.buffer.size".
It does default to 1MB, so something does not quite add up
Let me check that code path to understand who is using that parameter and how. 
> HBase on Hadoop 2 with local short circuit reads (ssr) causes OOM 
> ------------------------------------------------------------------
>                 Key: HBASE-8143
>                 URL: https://issues.apache.org/jira/browse/HBASE-8143
>             Project: HBase
>          Issue Type: Bug
>          Components: hadoop2
>    Affects Versions: 0.95.0, 0.98.0, 0.94.7
>            Reporter: Enis Soztutar
>            Assignee: Enis Soztutar
>             Fix For: 0.95.0, 0.98.0, 0.94.7
> We've run into an issue with HBase 0.94 on Hadoop2, with SSR turned on that the memory
usage of the HBase process grows to 7g, on an -Xmx3g, after some time, this causes OOM for
the RSs. 
> Upon further investigation, I've found out that we end up with 200 regions, each having
3-4 store files open. Under hadoop2 SSR, BlockReaderLocal allocates DirectBuffers, which is
unlike HDFS 1 where there is no direct buffer allocation. 
> It seems that there is no guards against the memory used by local buffers in hdfs 2,
and having a large number of open files causes multiple GB of memory to be consumed from the
RS process. 
> This issue is to further investigate what is going on. Whether we can limit the memory
usage in HDFS, or HBase, and/or document the setup. 
> Possible mitigation scenarios are: 
>  - Turn off SSR for Hadoop 2
>  - Ensure that there is enough unallocated memory for the RS based on expected # of store
>  - Ensure that there is lower number of regions per region server (hence number of open
> Stack trace:
> {code}
> org.apache.hadoop.hbase.DroppedSnapshotException: region: IntegrationTestLoadAndVerify,yC^P\xD7\x945\xD4,1363388517630.24655343d8d356ef708732f34cfe8946.
>         at org.apache.hadoop.hbase.regionserver.HRegion.internalFlushcache(HRegion.java:1560)
>         at org.apache.hadoop.hbase.regionserver.HRegion.internalFlushcache(HRegion.java:1439)
>         at org.apache.hadoop.hbase.regionserver.HRegion.flushcache(HRegion.java:1380)
>         at org.apache.hadoop.hbase.regionserver.MemStoreFlusher.flushRegion(MemStoreFlusher.java:449)
>         at org.apache.hadoop.hbase.regionserver.MemStoreFlusher.flushOneForGlobalPressure(MemStoreFlusher.java:215)
>         at org.apache.hadoop.hbase.regionserver.MemStoreFlusher.access$500(MemStoreFlusher.java:63)
>         at org.apache.hadoop.hbase.regionserver.MemStoreFlusher$FlushHandler.run(MemStoreFlusher.java:237)
>         at java.lang.Thread.run(Thread.java:662)
> Caused by: java.lang.OutOfMemoryError: Direct buffer memory
>         at java.nio.Bits.reserveMemory(Bits.java:632)
>         at java.nio.DirectByteBuffer.<init>(DirectByteBuffer.java:97)
>         at java.nio.ByteBuffer.allocateDirect(ByteBuffer.java:288)
>         at org.apache.hadoop.hdfs.util.DirectBufferPool.getBuffer(DirectBufferPool.java:70)
>         at org.apache.hadoop.hdfs.BlockReaderLocal.<init>(BlockReaderLocal.java:315)
>         at org.apache.hadoop.hdfs.BlockReaderLocal.newBlockReader(BlockReaderLocal.java:208)
>         at org.apache.hadoop.hdfs.DFSClient.getLocalBlockReader(DFSClient.java:790)
>         at org.apache.hadoop.hdfs.DFSInputStream.getBlockReader(DFSInputStream.java:888)
>         at org.apache.hadoop.hdfs.DFSInputStream.blockSeekTo(DFSInputStream.java:455)
>         at org.apache.hadoop.hdfs.DFSInputStream.readWithStrategy(DFSInputStream.java:645)
>         at org.apache.hadoop.hdfs.DFSInputStream.read(DFSInputStream.java:689)
>         at java.io.DataInputStream.readFully(DataInputStream.java:178)
>         at org.apache.hadoop.hbase.io.hfile.FixedFileTrailer.readFromStream(FixedFileTrailer.java:312)
>         at org.apache.hadoop.hbase.io.hfile.HFile.pickReaderVersion(HFile.java:543)
>         at org.apache.hadoop.hbase.io.hfile.HFile.createReaderWithEncoding(HFile.java:589)
>         at org.apache.hadoop.hbase.regionserver.StoreFile$Reader.<init>(StoreFile.java:1261)
>         at org.apache.hadoop.hbase.regionserver.StoreFile.open(StoreFile.java:512)
>         at org.apache.hadoop.hbase.regionserver.StoreFile.createReader(StoreFile.java:603)
>         at org.apache.hadoop.hbase.regionserver.Store.validateStoreFile(Store.java:1568)
>         at org.apache.hadoop.hbase.regionserver.Store.commitFile(Store.java:845)
>         at org.apache.hadoop.hbase.regionserver.Store.access$500(Store.java:109)
>         at org.apache.hadoop.hbase.regionserver.Store$StoreFlusherImpl.commit(Store.java:2209)
>         at org.apache.hadoop.hbase.regionserver.HRegion.internalFlushcache(HRegion.java:1541)
> {code}

This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira

View raw message