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Posted to commits@cassandra.apache.org by "Hudson (JIRA)" <ji...@apache.org> on 2011/02/10 01:44:57 UTC
[jira] Commented: (CASSANDRA-2148) system CFs default to large
memtable throughputs on large heaps
[ https://issues.apache.org/jira/browse/CASSANDRA-2148?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12992813#comment-12992813 ]
Hudson commented on CASSANDRA-2148:
-----------------------------------
Integrated in Cassandra-0.7 #272 (See [https://hudson.apache.org/hudson/job/Cassandra-0.7/272/])
bound hints CF memtable throughput between 32M and 256M
Patch by Matthew Dennis, reviewed by brandonwilliams for CASSANDRA-2148
> system CFs default to large memtable throughputs on large heaps
> ---------------------------------------------------------------
>
> Key: CASSANDRA-2148
> URL: https://issues.apache.org/jira/browse/CASSANDRA-2148
> Project: Cassandra
> Issue Type: Bug
> Affects Versions: 0.7.0
> Reporter: Matthew F. Dennis
> Assignee: Matthew F. Dennis
> Fix For: 0.7.1
>
> Attachments: 2148-cassandra-0.7.txt
>
>
> The default memtableThroughputInMB is calculated now based on the heap size. Most people running with a large heap in production explicitly set it for their memtable(s). However, the the CFs in the system keyspace still default to the calculated value which on a large heap can be quite large. HintsColumnFamily is really the only problematic one though as the others are flushed afters changes to them.
> we should:
> 1) set the throughput on the hints CF to a reasonable max and min value - min(256, max(32, normalDefault/2))
> 2) set the throughput on the other system CFs to some small constant value (just as a safety); 8M sounds good
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