[
https://issues.apache.org/jira/browse/HBASE-14460?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15057635#comment-15057635
]
stack commented on HBASE-14460:
-------------------------------
[[email protected]]
But at the start of the increment when we do this...
mvcc.await(rowLockPair.getFirst().getRowOperationContext());
... the rowOperationContext does not have our rows sequenceid, right? That does
not get assigned much later when we do the append way down inside this method.
The mvcc.await at the head of the increment is working with the initial
setting, -1, so is not waiting at all?
Maybe I am not following. Please correct me if I am misreading. Thanks
[[email protected]]
The difference you see when you run the test is interesting in of it itself.
> [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.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
