[jira] [Commented] (CASSANDRA-5549) Remove Table.switchLock

["Ryan McGuire (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-5549?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13750184#comment-13750184 ] 

Ryan McGuire commented on CASSANDRA-5549:
-----------------------------------------

[~jbellis] I ran a benchmark against your branch comparing it to the prior commit. I didn't see any difference in write performance:

!5549-removed-switchlock.png!

[Data for this benchmark here|http://ryanmcguire.info/ds/graph/graph.html?stats=stats.removed_switchlock.json&metric=interval_op_rate&operation=stress-write&smoothing=1]
                
> Remove Table.switchLock
> -----------------------
>
>                 Key: CASSANDRA-5549
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-5549
>             Project: Cassandra
>          Issue Type: Bug
>            Reporter: Jonathan Ellis
>             Fix For: 2.1
>
>         Attachments: 5549-removed-switchlock.png
>
>
> As discussed in CASSANDRA-5422, Table.switchLock is a bottleneck on the write path.  ReentrantReadWriteLock is not lightweight, even if there is no contention per se between readers and writers of the lock (in Cassandra, memtable updates and switches).

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira