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https://issues.apache.org/jira/browse/HBASE-17757?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15900866#comment-15900866
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Anoop Sam John edited comment on HBASE-17757 at 3/8/17 7:51 AM:
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In case where both DBE and compression in use, the size we track will be after
compression also. And what we keep in cache is uncompressed blocks (By default.
There is config to keep compressed also).. So the math will go wrong there?
Now also the block sizes for BucketCache has to be tuned considering the
encoding factor. Ya it makes the size restrictions bit more clear. So when
there is compression also in place, need to adjust the factor accordingly say
0.5 to 0.3 (eg: )
was (Author: anoop.hbase):
In case where both DBE and compression in use, the size we track will be after
compression also. And what we keep in cache is uncompressed blocks (By default.
There is config to keep compressed also).. So the math will go wrong there?
Now also the block sizes for BucketCache has to be tuned considering the
encoding factor. Ya it makes the size restrictions bit more clear. So when
there is compression also in place, need to adjust the factor accordingly say
0.5 to 0.3 (eg:)
> Unify blocksize after encoding to decrease memory fragment
> -----------------------------------------------------------
>
> Key: HBASE-17757
> URL: https://issues.apache.org/jira/browse/HBASE-17757
> Project: HBase
> Issue Type: New Feature
> Reporter: Allan Yang
> Assignee: Allan Yang
> Attachments: HBASE-17757.patch
>
>
> Usually, we store encoded block(uncompressed) in blockcache/bucketCache.
> Though we have set the blocksize, after encoding, blocksize is varied. Varied
> blocksize will cause memory fragment problem, which will result in more FGC
> finally.In order to relief the memory fragment, This issue adjusts the
> encoded block to a unified size.
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