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https://issues.apache.org/jira/browse/HBASE-18294?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16352186#comment-16352186
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Eshcar Hillel commented on HBASE-18294:
---------------------------------------

I would generally agree with your approach [~chancelq] - simple abstraction are 
usually the right way to go. However, the user controls the sizes of memory 
allocated on-heap and off-heap and if we are not care to respect both limits we 
may end up crossing one of them and getting OOME even if the "global" memory is 
not exhausted.

Specifically, you can review the discussion from December 28 above.

> Reduce global heap pressure: flush based on heap occupancy
> ----------------------------------------------------------
>
>                 Key: HBASE-18294
>                 URL: https://issues.apache.org/jira/browse/HBASE-18294
>             Project: HBase
>          Issue Type: Improvement
>    Affects Versions: 3.0.0
>            Reporter: Eshcar Hillel
>            Assignee: Eshcar Hillel
>            Priority: Major
>             Fix For: 2.0.0-beta-2
>
>         Attachments: HBASE-18294.01.patch, HBASE-18294.01.patch, 
> HBASE-18294.01.patch, HBASE-18294.01.patch, HBASE-18294.02.patch, 
> HBASE-18294.03.patch, HBASE-18294.04.patch, HBASE-18294.05.patch, 
> HBASE-18294.06.patch, HBASE-18294.07.patch, HBASE-18294.07.patch, 
> HBASE-18294.08.patch, HBASE-18294.09.patch, HBASE-18294.10.patch, 
> HBASE-18294.11.patch, HBASE-18294.11.patch, HBASE-18294.12.patch, 
> HBASE-18294.13.patch, HBASE-18294.15.patch, HBASE-18294.16.patch, 
> HBASE-18294.master.01.patch
>
>
> A region is flushed if its memory component exceed a threshold (default size 
> is 128MB).
> A flush policy decides whether to flush a store by comparing the size of the 
> store to another threshold (that can be configured with 
> hbase.hregion.percolumnfamilyflush.size.lower.bound).
> Currently the implementation (in both cases) compares the data size 
> (key-value only) to the threshold where it should compare the heap size 
> (which includes index size, and metadata).



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