You are viewing a plain text version of this content. The canonical link for it is here.
Posted to commits@cassandra.apache.org by "Stu Hood (JIRA)" <ji...@apache.org> on 2011/09/09 20:37:09 UTC
[jira] [Commented] (CASSANDRA-3168) Arena allocation causes
excessive flushing on small heaps
[ https://issues.apache.org/jira/browse/CASSANDRA-3168?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13101451#comment-13101451 ]
Stu Hood commented on CASSANDRA-3168:
-------------------------------------
+1.
> Arena allocation causes excessive flushing on small heaps
> ---------------------------------------------------------
>
> Key: CASSANDRA-3168
> URL: https://issues.apache.org/jira/browse/CASSANDRA-3168
> Project: Cassandra
> Issue Type: Bug
> Affects Versions: 1.0.0
> Reporter: Jonathan Ellis
> Assignee: Jonathan Ellis
> Fix For: 1.0.0
>
> Attachments: 0002-3168.txt, 3168.txt
>
>
> adding allocator.size() to Memtable.getLiveSize has two problems:
> 1) it double-counts allocated parts of regions
> 2) it makes the size of an empty memtable the size of a single region
> (2) is a particular problem because flushing a nearly-empty memtable will not actually free up much memory -- we just trade one almost-empty region, for another. In testing, I even saw this happening to the low-traffic system tables like LocationInfo.
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira