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Date: Sat, 25 Jan 2014 01:09:41 +0000 (UTC)
From: "Jonathan Ellis (JIRA)" <jira@apache.org>
To: commits@cassandra.apache.org
Message-ID: <JIRA.12646554.1367987562398.10194.1390612181095@arcas>
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Subject: [jira] [Commented] (CASSANDRA-5549) Remove Table.switchLock
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    [ https://issues.apache.org/jira/browse/CASSANDRA-5549?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13881584#comment-13881584 ] 

Jonathan Ellis commented on CASSANDRA-5549:
-------------------------------------------

I think what I'm having a hard time with is, Pool should be a reservoir that we allocate out of and instead it's a container of two such reservoirs (MT).  I propose renaming:

MemoryTracker -> Pool
Pool -> LinkedPools?  DualPool?  OnOffHeapPools?  Reservoir?  PoolPool?

> 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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