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https://issues.apache.org/jira/browse/CASSANDRA-1305?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Daniel Kluesing updated CASSANDRA-1305:
---------------------------------------

    Attachment: trunk-SlowQueryLog.txt

There are lots of knobs to tune (row cache, key cache, index sample size, bloom 
filter buckets, network, disk, heap) Figuring out what to tune under load isn't 
always obvious. Turning on debug logging under load has heisenberg effect of 
shifting bottlenecks around. The attached patch is a simple slow query logger 
to log information about what queries that take longer than some threshold did 
that took so long. I've found it useful for pinpointing bottlenecks under load 
and figuring out which knobs need tweaking. This patch only instruments the 
get_slice command and the read path. Incrementing the other commands/paths is 
straightforward, and I update the patch with the write path.


> Slow query log
> --------------
>
>                 Key: CASSANDRA-1305
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-1305
>             Project: Cassandra
>          Issue Type: New Feature
>            Reporter: Daniel Kluesing
>            Priority: Minor
>         Attachments: trunk-SlowQueryLog.txt
>
>
> If a query takes a long time, it's nice to know why

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