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https://issues.apache.org/jira/browse/HBASE-15204?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15135860#comment-15135860
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ramkrishna.s.vasudevan commented on HBASE-15204:
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bq.So, the call to the cp contract should be updated to say something like, "if
you add new cells, you MUST return the count of cells added in the result ...
else they will be ignored"... something like that?
Stack, I think I can explain here. There is nothing am doing with the CP call
here. The code in doPreMutationHook calls all the prehooks and we collect all
those WALEdits already. Am just using that WALEdits and counting the size.
There is no need for any contract on the CP side for doing this. While we
collect those WALEdits into the 'batchOp.walEditsFromCoprocessors' already. If
there was no edit added from CP this count is going to be 0. No contract
explicitly added here.
Simple way to not pass this cellcout is just to add those cellCount to the
BatchOp directly and then use a getter to add the actual cellCount.
> Try to estimate the cell count for adding into WALEdit
> ------------------------------------------------------
>
> Key: HBASE-15204
> URL: https://issues.apache.org/jira/browse/HBASE-15204
> Project: HBase
> Issue Type: Sub-task
> Components: regionserver
> Reporter: ramkrishna.s.vasudevan
> Assignee: ramkrishna.s.vasudevan
> Fix For: 2.0.0, 1.3.0
>
> Attachments: HBASE-15204.patch, HBASE-15204_1.patch,
> HBASE-15204_1.patch, WAlEdit_add_allocation.jpg,
> WAlEdit_add_allocation_after_patch.jpg
>
>
> The write path profiling shows that when we try to add Cells to WALEdits we
> try to do a lot of Array copy inorder to grow the Arraylist backing the
> WALEdits. In a simple one min profiling of the write path with 50 YCSB
> threads shows around 261MB of allocation done for the Array copy to happen.
> We can try to avoid that.
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