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https://issues.apache.org/jira/browse/HBASE-14978?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Elliott Clark updated HBASE-14978:
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Labels: (was: needs_releasenote)
Release Note:
Limiting the amount of memory resident for any one request allows the server to
handle concurrent requests smoothly. To this end we added the ability to limit
the size of responses to a multi request. That worked well however it correctly
represent the amount of memory resident. So this issue adds on a an
approximation of the number of blocks held for a request.
All clients before 1.2.0 will not get this multi request chunking based upon
blocks kept. All clients 1.2.0 and after will.
> Don't allow Multi to retain too many blocks
> -------------------------------------------
>
> Key: HBASE-14978
> URL: https://issues.apache.org/jira/browse/HBASE-14978
> Project: HBase
> Issue Type: Improvement
> Components: io, IPC/RPC, regionserver
> Affects Versions: 2.0.0, 1.2.0, 1.3.0
> Reporter: Elliott Clark
> Assignee: Elliott Clark
> Priority: Blocker
> Fix For: 1.2.0, 3.0.0, 1.3.0
>
> Attachments: HBASE-14978-branch-1.2.patch,
> HBASE-14978-branch-1.2.patch, HBASE-14978-branch-1.2.patch,
> HBASE-14978-branch-1.2.patch, HBASE-14978-v1.patch, HBASE-14978-v2.patch,
> HBASE-14978-v3.patch, HBASE-14978-v4.patch, HBASE-14978.patch
>
>
> Scans and Multi's have limits on the total size of cells that can be
> returned. However if those requests are not all pointing at the same blocks
> then the KeyValues can keep alive a lot more data than their size.
> Take the following example:
> A multi with a list of 10000 gets to a fat row. Each column being returned in
> in a different block. Each column is small 32 bytes or so.
> So the total cell size will be 32 * 10000 = ~320kb. However if each block is
> 128k then total retained heap size will be almost 2gigs.
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