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https://issues.apache.org/jira/browse/HBASE-3504?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12990470#comment-12990470
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dhruba borthakur commented on HBASE-3504:
-----------------------------------------
One proposal is to make it a ReadWrite lock. The log roller should acquire the
lock in Write mode while the HLog.append() calls could acquire it in Read mode.
On a related note, I see a possible bug in the existing code where the
logSyncer thread invokes HDFS.sync on a writer that has already been closed by
the log-roller.This could happen because the logSyncer thread does not acquire
the updateLock while invoking HDFS sync on the writer.
> HLog performance improvement
> ----------------------------
>
> Key: HBASE-3504
> URL: https://issues.apache.org/jira/browse/HBASE-3504
> Project: HBase
> Issue Type: Improvement
> Components: regionserver
> Reporter: dhruba borthakur
> Assignee: dhruba borthakur
>
> The HLog.updateLock protects the rolling of logs with concurrent writes to
> the HDFS log file. This is a scalability bottleneck for a workload that
> comprises mostly of counter-increments.
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