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Posted to dev@hbase.apache.org by "Elliott Clark (JIRA)" <ji...@apache.org> on 2015/12/15 01:29:46 UTC

[jira] [Created] (HBASE-14978) Don't allow Scans and Multi to retain too many blocks

Elliott Clark created HBASE-14978:
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             Summary: Don't allow Scans and Multi to retain too many blocks
                 Key: HBASE-14978
                 URL: https://issues.apache.org/jira/browse/HBASE-14978
             Project: HBase
          Issue Type: Improvement
            Reporter: Elliott Clark
            Assignee: Elliott Clark


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 40gigs.



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