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https://issues.apache.org/jira/browse/ACCUMULO-4112?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15108802#comment-15108802
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Eric Newton commented on ACCUMULO-4112:
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I've updated the test. The test performs a series of Conditional updates on a
table with many tablets. I lowered the durability on the metadata table to
flush.
I ran the test sending the "start MinC" and "stop MinC" writes to the WALog at
different durabilities. The screenshot of the performance differences is shown.
It should be noted that the performance for a single tablet is always much
faster, even with full sync Durability.
> MinC start/stop updates are always hsync'd
> ------------------------------------------
>
> Key: ACCUMULO-4112
> URL: https://issues.apache.org/jira/browse/ACCUMULO-4112
> Project: Accumulo
> Issue Type: Bug
> Components: tserver
> Environment: Fluo testing on a 20-node cluster
> Reporter: Eric Newton
> Assignee: Eric Newton
> Priority: Minor
> Attachments: MinCFlushPerfTest.java, Sync-Flush-Log-Performance.png
>
>
> [~kturner] writes:
> {quote}
> I was running a Fluo test with 1.8.0-SNAP on my workstation. My Fluo table
> had a ton of tablets. I was seeing terrible performance. I started
> looking at the tserver and noticed it was always calling hsync. I tracked
> down the problem to the fact that when minc start and stop events are written
> to the log they are always written w/ sync level. My poor little tserver
> was constantly minor compacting (probably had around 600 tablets that were
> all being written to).
> I changed the test config to create like 15 tablets and the performance was
> much better. All cores were 100% utilized, which was not the case when hsync
> was always called.
> {quote}
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