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From David Medinets <david.medin...@gmail.com>
Subject Re: [jira] [Commented] (ACCUMULO-624) iterators may open lots of compressors
Date Thu, 21 Jun 2012 17:38:39 GMT
Is the testing code simple enough to attach to this ticket? I ask
because others might want to replicate your results.

On Thu, Jun 21, 2012 at 12:27 PM, Keith Turner (JIRA) <jira@apache.org> wrote:
>
>    [ https://issues.apache.org/jira/browse/ACCUMULO-624?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13398538#comment-13398538
]
>
> Keith Turner commented on ACCUMULO-624:
> ---------------------------------------
>
> A work around for this issue is to enable the block cache for the table.  This will
cause rfile blocks to be read into memory and closed immediately, releasing the decompressor.
 A decompressor will not be kept for each deep copy in this case.
>
> I did some test with the intersecting iterator to verify this.  W/o cache querying 5
terms would allocate 5 decompressors.  W/ cache only one decompressor was allocated.
>
>> iterators may open lots of compressors
>> --------------------------------------
>>
>>                 Key: ACCUMULO-624
>>                 URL: https://issues.apache.org/jira/browse/ACCUMULO-624
>>             Project: Accumulo
>>          Issue Type: Bug
>>          Components: tserver
>>            Reporter: Eric Newton
>>            Assignee: Keith Turner
>>
>> A large iterator tree may create many instances of Compressors.  These instances
are pulled from a pool that never decreases in size.  So, if 50 simultaneous queries are
run over dozens of files, each with a complex iterator stack, there will be thousands of compressors
created.  Each of these holds a large buffer.  This can cause the server to run out of memory.
>
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