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https://issues.apache.org/jira/browse/CASSANDRA-1305?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12890323#action_12890323
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Daniel Kluesing edited comment on CASSANDRA-1305 at 7/20/10 1:02 PM:
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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 can update the patch with the write path.
was (Author: danielkluesing_bk):
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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