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https://issues.apache.org/jira/browse/CASSANDRA-1123?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13442949#comment-13442949
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David Alves commented on CASSANDRA-1123:
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bq. Hmm, can we do something clever like
http://stackoverflow.com/questions/4046228/log4j-excluding-the-logging-of-some-classes
to just log o.a.c.tracing to stdout + R so we don't just error out silently
when something goes wrong w/ tracing?
after I had done this I realized that there was no point. all log events from
everywhere (including o.a.c.tracing) but the ones coming from tracing stage
executions are already present in all logs (tracing, rolling and stdout) if at
the debug level. tracing writes do not inherit the debuggableTPE, which means
log events coming from a tracing write do not go the tracing appender but *do*
go the rest of the appenders by default already.
> Allow tracing query details
> ---------------------------
>
> Key: CASSANDRA-1123
> URL: https://issues.apache.org/jira/browse/CASSANDRA-1123
> Project: Cassandra
> Issue Type: New Feature
> Components: Core
> Reporter: Jonathan Ellis
> Assignee: David Alves
> Fix For: 1.2.0 beta 1
>
> Attachments: 1123-3.patch.gz, 1123.patch, 1123.patch, 1123.patch,
> 1123.patch, 1123-v6.txt, 1123-v7.patch
>
>
> In the spirit of CASSANDRA-511, it would be useful to tracing on queries to
> see where latency is coming from: how long did row cache lookup take? key
> search in the index? merging the data from the sstables? etc.
> The main difference vs setting debug logging is that debug logging is too big
> of a hammer; by turning on the flood of logging for everyone, you actually
> distort the information you're looking for. This would be something you
> could set per-query (or more likely per connection).
> We don't need to be as sophisticated as the techniques discussed in the
> following papers but they are interesting reading:
> http://research.google.com/pubs/pub36356.html
> http://www.usenix.org/events/osdi04/tech/full_papers/barham/barham_html/
> http://www.usenix.org/event/nsdi07/tech/fonseca.html
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