[
https://issues.apache.org/jira/browse/HBASE-14460?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15057465#comment-15057465
]
stack edited comment on HBASE-14460 at 12/15/15 7:06 AM:
---------------------------------------------------------
[[email protected]] I'm not clear on how your patch works. Please explain
it to those who are slower than you.
I see that at the start of the Increment, when we begin mvcc, we pass in this
new RowContext. I see then that in begin, we run through contexts looking at
write numbers to find the highest write number on a row which I suppose could
be less than the one we are assigned by default; that'd be good. How is row
write number assigned?
Thanks.
was (Author: stack):
[[email protected]] I'm not clear on how your patch works. Please explain
it to those who are slower than you.
I see that at the start of the Incrment, when we being mvcc, we pass in this
new RowContext. I see then that in begin, we run through contexts looking at
write numbers to find the highest write number on a row which I suppose could
be less than the one we are assigned by default; that'd be good. How is row
write number assigned?
Thanks.
> [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)
