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https://issues.apache.org/jira/browse/CASSANDRA-1123?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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David Alves updated CASSANDRA-1123:
-----------------------------------
Attachment: 1123.patch
First patch that implements most of what was suggested, with accompanying test.
Still to define/discuss:
- aaraons "replaced" the logger with meant there were already a lot of things
being logged. As is this patch is pretty "bare" in terms of trace events in the
sense that stuff that goes through CassandraServer gets a new trace session but
not much else is traced (even though session gets propagated across threads and
nodes). Maybe we could add events automatically when a session is propagated
across stages and across nodes?
- I haven't added the log to the logger option yet, as I'm not completely sure
how useful it is if events are generated per stage/node.
> 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
>
> Attachments: 1123-3.patch.gz, 1123.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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