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https://issues.apache.org/jira/browse/HBASE-21806?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16755569#comment-16755569
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Duo Zhang commented on HBASE-21806:
-----------------------------------
I think the default value is too high, even for OLAP clusters.
Skimmed the patch, overall LGTM. +1.
{code}
LOG.info("Trying to request a roll due to a very log sync ({} ms)", timeInNanos
/ 1000000);
{code}
This could be a typo? 'very log sync' => 'very long sync' or 'very long log
sync'?
> add an option to roll WAL on very slow syncs
> --------------------------------------------
>
> Key: HBASE-21806
> URL: https://issues.apache.org/jira/browse/HBASE-21806
> Project: HBase
> Issue Type: Bug
> Reporter: Sergey Shelukhin
> Assignee: Sergey Shelukhin
> Priority: Major
> Attachments: HBASE-21806.patch
>
>
> In large heterogeneous clusters sometimes a slow datanode can cause WAL syncs
> to be very slow. In this case, before the bad datanode recovers, or is
> discovered and repaired, it would be helpful to roll WAL on a very slow sync
> to get a new pipeline.
> Otherwise the slow WAL will impact write latency for a long time (slow writes
> result in less writes result in the WAL not being rolled for longer)
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