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https://issues.apache.org/jira/browse/HBASE-14460?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15060191#comment-15060191
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Jingcheng Du commented on HBASE-14460:
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There is an issue in this patch. The RowContext is released when the lock is
released, it is before mvcc.completeAndWait is finished. It means the following
operations cannot get the lastWriteNumber before the last operation is
completed indeed because the cached context had been cleaned. We should clear
the cached context a little later and right after mvcc.completeAndWait.
> [Perf Regression] Merge of MVCC and SequenceId (HBASE-HBASE-8763) slowed
> Increments, CheckAndPuts, batch operations
> -------------------------------------------------------------------------------------------------------------------
>
> Key: HBASE-14460
> URL: https://issues.apache.org/jira/browse/HBASE-14460
> Project: HBase
> Issue Type: Bug
> Components: Performance
> Reporter: stack
> Assignee: stack
> Priority: Critical
> Attachments: 0.94.test.patch, 0.98.test.patch,
> 1.0.80.flamegraph-7932.svg, 14460.txt, 98.80.flamegraph-11428.svg,
> HBASE-14460-discussion.patch, client.test.patch,
> flamegraph-13120.svg.master.singlecell.svg, flamegraph-26636.094.100.svg,
> flamegraph-28066.098.singlecell.svg, flamegraph-28767.098.100.svg,
> flamegraph-31647.master.100.svg, flamegraph-9466.094.singlecell.svg,
> m.test.patch, region_lock.png, testincrement.094.patch,
> testincrement.098.patch, testincrement.master.patch
>
>
> As reported by 鈴木俊裕 up on the mailing list -- see "Performance degradation
> between CDH5.3.1(HBase0.98.6) and CDH5.4.5(HBase1.0.0)" -- our unification of
> sequenceid and MVCC slows Increments (and other ops) as the mvcc needs to
> 'catch up' to our current point before we can read the last Increment value
> that we need to update.
> We can say that our Increment is just done wrong, we should just be writing
> Increments and summing on read, but checkAndPut as well as batching
> operations have the same issue. Fix.
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