hbase-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "chunhui shen (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-10205) ConcurrentModificationException in BucketAllocator
Date Fri, 20 Dec 2013 03:32:11 GMT

    [ https://issues.apache.org/jira/browse/HBASE-10205?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13853636#comment-13853636
] 

chunhui shen commented on HBASE-10205:
--------------------------------------

I think the contention  on the BucketAllocator won't be the bottleneck of writer threads.

AllocateBlock() are only  triggerd after we miss the block from cache and get block from HDFS,

In that case, IOPS is the bottleneck of system.


> ConcurrentModificationException in BucketAllocator
> --------------------------------------------------
>
>                 Key: HBASE-10205
>                 URL: https://issues.apache.org/jira/browse/HBASE-10205
>             Project: HBase
>          Issue Type: Bug
>          Components: regionserver
>    Affects Versions: 0.89-fb
>            Reporter: Arjen Roodselaar
>            Assignee: Arjen Roodselaar
>            Priority: Minor
>             Fix For: 0.89-fb, 0.99.0
>
>         Attachments: hbase-10205-trunk.patch
>
>
> The BucketCache WriterThread calls BucketCache.freeSpace() upon draining the RAM queue
containing entries to be cached. freeSpace() in turn calls BucketSizeInfo.statistics() through
BucketAllocator.getIndexStatistics(), which iterates over 'bucketList'. At the same time another
WriterThread might call BucketAllocator.allocateBlock(), which may call BucketSizeInfo.allocateBlock(),
add a bucket to 'bucketList' and consequently cause a ConcurrentModificationException. Calls
to BucketAllocator.allocateBlock() are synchronized, but calls to BucketAllocator.getIndexStatistics()
are not, which allows this race to occur.



--
This message was sent by Atlassian JIRA
(v6.1.4#6159)

Mime
View raw message