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https://issues.apache.org/jira/browse/HBASE-17035?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15643418#comment-15643418
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ramkrishna.s.vasudevan commented on HBASE-17035:
------------------------------------------------
I think this is the case. Pls do correct me if am wrong.
-> WE have an active Writer (say w1). We do sequence of appends/sync calls on
this. Say we now do a synccompleted() and there we request a log roll.
-> Before the log roll request is completed we waitForSafePoint(). We just
check if we can schedule a task or not but there is a sycn on
waitingConsumePayloads.
-> Now before the log roll request is processed since the writer is still not
swapped out we do accept more appends. In consume()
{code}
final AsyncWriter writer = this.writer;
{code}
We do this. The writer is still the older one.
-> Now the log roll request tries to get completed and it creates W2. And the
writer instance is updated.
-> By the time the appends that were added on W1 will now again see that the
size is bigger than logRollSize and trigger a logRoll. But this time the again
the logRoll happens but it will now account for the size of W2 only since that
is the writer instance active now and it will create a new file W3.
> Check why we roll a wal writer at 10MB when the configured roll size is 120M+
> with AsyncFSWAL
> ---------------------------------------------------------------------------------------------
>
> Key: HBASE-17035
> URL: https://issues.apache.org/jira/browse/HBASE-17035
> Project: HBase
> Issue Type: Sub-task
> Components: wal
> Affects Versions: 2.0.0
> Reporter: Duo Zhang
> Assignee: Duo Zhang
> Fix For: 2.0.0
>
>
> Found this when addressing HBASE-16890. It is one of the possible reason that
> why AsyncFSWAL performs worse than FSHLog when running PE tool.
> https://issues.apache.org/jira/browse/HBASE-16890?focusedCommentId=15636688&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-15636688
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