[
https://issues.apache.org/jira/browse/HBASE-14460?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15061361#comment-15061361
]
Jingcheng Du commented on HBASE-14460:
--------------------------------------
[~stack], I got your and [~eclark]'s ideas. It tries to use write lock to
guarantee there is not earlier entries on this row.
Does it impact if the wal sync is included in the write lock (During the test,
it uses WAL_SKIP, right?)? What if users enable the wal, would it be much
worse? Please advise.
> [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,
> hack.flamegraph-16593.svg, hack.uncommitted.patch, 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.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
