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Posted to commits@cassandra.apache.org by "Ariel Weisberg (JIRA)" <ji...@apache.org> on 2016/07/29 22:29:20 UTC
[jira] [Comment Edited] (CASSANDRA-12228) Write performance
regression in 3.x vs 3.0
[ https://issues.apache.org/jira/browse/CASSANDRA-12228?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15400133#comment-15400133 ]
Ariel Weisberg edited comment on CASSANDRA-12228 at 7/29/16 10:28 PM:
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There are some remaining issues with thread pool sizes. See [CASSANDRA-12071|https://issues.apache.org/jira/browse/CASSANDRA-12071?focusedCommentId=15400086&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-15400086].
You still can't get multiple threads if you have a single disk due to TPE not spinning up additional threads if you are using an unbounded queue. Seems like this would be a good place to address the related issue. I also don't think this is minor it's pretty crippling for performance and you can't work around it by changing configuration values.
was (Author: aweisberg):
There are some remaining issues with thread pool sizes. See [CASSANDRA-12071|https://issues.apache.org/jira/browse/CASSANDRA-12071?focusedCommentId=15400086&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-15400086].
You still can't get multiple threads if you have a single disk. Seems like this would be a good place to address the related issue. I also don't think this is minor it's pretty crippling for performance and you can't work around it by changing configuration values.
> Write performance regression in 3.x vs 3.0
> ------------------------------------------
>
> Key: CASSANDRA-12228
> URL: https://issues.apache.org/jira/browse/CASSANDRA-12228
> Project: Cassandra
> Issue Type: Bug
> Reporter: T Jake Luciani
> Assignee: Marcus Eriksson
> Priority: Minor
> Fix For: 3.9
>
>
> I've been tracking down a performance issue in trunk vs cassandra-3.0 branch.
> I think I've found it. CASSANDRA-6696 changed the default memtable flush default to 1 vs the min of 2 in cassandra-3.0.
> I don't see any technical reason for this and we should add back the min of 2 sstable flushers per disk.
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