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https://issues.apache.org/jira/browse/HBASE-14460?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15057499#comment-15057499
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Jingcheng Du commented on HBASE-14460:
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Most of the difference is what mvcc.await does in the beginning of the
increment, checkAndMutate, etc. operations, it only waits for the operations in
its row. In the mvcc.await after the operations, it is the same with the
current way to wait for the finish of the current operation.
If it is a batch operation, all the row operation context in that batch will
have the same write number of a WriteEntry. This write number will be used in
mvcc.await method in the beginning of next increment operation.
> [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, 14460.txt,
> HBASE-14460-discussion.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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