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From DE VITO Dominique <dominique.dev...@thalesgroup.com>
Subject RE: Log Slow Queries
Date Thu, 18 Jun 2015 11:21:40 GMT
Hi Carlos,

Different possibilities (to log slow queries).


1)      A probabilistic way to catch slow queries (probabilistic, but with detailed info)
=> look for “nodetool settraceprobability” like in http://www.datastax.com/dev/blog/advanced-request-tracing-in-cassandra-1-2


2)      Catch slow queries in the driver (it’s a recent feature, available for newest drivers
only) => see http://datastax.github.io/java-driver/2.0.10/features/logging/#logging-query-latencies


3)      Catch slow queries on server-side (but only with C* 2.1) => see slides 15-17 "Lesser
Known Features of Cassandra 2.1" http://fr.slideshare.net/planetcassandra/cassandra-summit-2014-lesser-known-features-of-cassandra-21


On our side, we are more keen to use (2) – which has the best ROI (IMHO).


Regards,
Dominique

[@@ THALES GROUP INTERNAL @@]

De : Carlos Alonso [mailto:info@mrcalonso.com]
Envoyé : jeudi 18 juin 2015 12:33
À : user@cassandra.apache.org
Objet : Log Slow Queries

Hi guys.

I'm facing slow read requests from time to time, I've spotted the keyspace/cf where this is
happening but I can't see anything obvious (single partition slice query, no tombstones, ...)
anything else where to look at?

I'd like to have the slow queries logged to either log or saved to a particular column family
to analyse them later. I've googled about this and the only 'easy' solution available out
there seems to be DataStax Enterprise.

What are you guys using?

Thanks,
Carlos Alonso | Software Engineer | @calonso<https://twitter.com/calonso>
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