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Posted to commits@cassandra.apache.org by "Sylvain Lebresne (JIRA)" <ji...@apache.org> on 2013/06/26 19:56:20 UTC
[jira] [Commented] (CASSANDRA-5534) Writing wide row causes high
CPU usage after compaction
[ https://issues.apache.org/jira/browse/CASSANDRA-5534?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13694121#comment-13694121 ]
Sylvain Lebresne commented on CASSANDRA-5534:
---------------------------------------------
Would you mind testing that again? I just tried the same test with current trunk and it's fast (< 2s for the whole stress).
> Writing wide row causes high CPU usage after compaction
> -------------------------------------------------------
>
> Key: CASSANDRA-5534
> URL: https://issues.apache.org/jira/browse/CASSANDRA-5534
> Project: Cassandra
> Issue Type: Bug
> Affects Versions: 2.0 beta 1
> Reporter: Ryan McGuire
> Assignee: Sylvain Lebresne
> Fix For: 2.0
>
> Attachments: wide_row_stress.trunk.log.txt.gz
>
>
> Introduced in commit -e74c13ff08663d306dcc5cdc99c07e9e6c12ca21- (see below) there is a significant slow down when creating a wide row with cassandra-stress:
> Testing with the prior (good) commit I used this to write a single wide row, which completed rather quickly:
> {code}
> $ ccm create -v git:60f09f0121e0801851b9ab017eddf7e326fa05fb wide-row
> Fetching Cassandra updates...
> Cloning Cassandra (from local cache)
> Checking out requested branch (60f09f0121e0801851b9ab017eddf7e326fa05fb)
> Compiling Cassandra 60f09f0121e0801851b9ab017eddf7e326fa05fb ...
> Current cluster is now: wide-row
> $ ccm populate -n 1
> $ ccm start
> $ time ccm node1 stress -c 10000 -S 1000 -n 1
> Created keyspaces. Sleeping 1s for propagation.
> total,interval_op_rate,interval_key_rate,latency/95th/99th,elapsed_time
> 1,0,0,273.3,273.3,273.3,0
> END
> real 0m7.106s
> user 0m1.710s
> sys 0m0.120s
> {code}
> Using the bugged commit (e74c13ff08663d306dcc5cdc99c07e9e6c12ca21) I get a significant slow down:
> {code}
> 02:42 PM:~$ ccm create -v git:e74c13ff08663d306dcc5cdc99c07e9e6c12ca21 wide-row
> Fetching Cassandra updates...
> Current cluster is now: wide-row
> 02:42 PM:~$ ccm populate -n 1
> 02:42 PM:~$ ccm start
> 02:42 PM:~$ time ccm node1 stress -c 10000 -S 1000 -n 1
> Created keyspaces. Sleeping 1s for propagation.
> total,interval_op_rate,interval_key_rate,latency,95th,99th,elapsed_time
> 1,0,0,423.2,423.2,423.2,0
> Total operation time : 00:00:00
> END
> real 4m16.394s
> user 0m2.230s
> sys 0m0.137s
> {code}
> Interestingly, the commit in question just says it's a merge from cassandra-1.2, but I do not see this same slowdown using that branch, this only occurs in trunk.
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