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https://issues.apache.org/jira/browse/CASSANDRA-5549?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13874831#comment-13874831
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Jonathan Ellis commented on CASSANDRA-5549:
-------------------------------------------

bq. issue() is the normal parlance when talking about memory fences

The problem is that it's not "just" a memory fence, but is tied to the Group 
behavior.  (Once issued, the old group is sealed and a new Group started.)

bq. isAfter()?

WFM.

> Remove Table.switchLock
> -----------------------
>
>                 Key: CASSANDRA-5549
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-5549
>             Project: Cassandra
>          Issue Type: Bug
>            Reporter: Jonathan Ellis
>            Assignee: Benedict
>              Labels: performance
>             Fix For: 2.1
>
>         Attachments: 5549-removed-switchlock.png, 5549-sunnyvale.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).



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