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https://issues.apache.org/jira/browse/CASSANDRA-1123?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13443258#comment-13443258
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Jonathan Ellis commented on CASSANDRA-1123:
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bq. an exception from a FutureTask will not be seen unless get() is called
Thus, the default exception handler doesn't matter. This is the main problem
DTPE solves. (That, and block-until-room-on-queue which is a better policy
than the defaults.)
I note that we always use .execute instead of .submit on the tracing stage for
now, but I'd like to cover our bases or this could be a real head-scratcher
if/when we do exercise the submit path.
> 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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