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https://issues.apache.org/jira/browse/HBASE-14460?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14904251#comment-14904251
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Heng Chen commented on HBASE-14460:
-----------------------------------
with [~stack] patch, the problem could be easily reproduced locally on
master...
All threads were blocked on the same position. They were waiting for the slow
write.
This is my jstack information
{code}
"9" #19 prio=5 os_prio=31 tid=0x00007fa8bcbe2800 nid=0x6103 in Object.wait()
[0x000000011d50c000]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
- waiting on <0x00000007887e8528> (a java.lang.Object)
at
org.apache.hadoop.hbase.regionserver.MultiVersionConcurrencyControl.waitForRead(MultiVersionConcurrencyControl.java:207)
- locked <0x00000007887e8528> (a java.lang.Object)
at
org.apache.hadoop.hbase.regionserver.MultiVersionConcurrencyControl.completeAndWait(MultiVersionConcurrencyControl.java:143)
at
org.apache.hadoop.hbase.regionserver.TestMultiVersionConcurrencyControlBasic$CycleSomeMvccOps.run(TestMultiVersionConcurrencyControlBasic.java:73)
{code}
> [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: 14460.txt, region_lock.png
>
>
> 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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