As Jonathan said, it's better to activate query tracing client side. It'll give you better flexibility of when to turn on & off tracing and on which table. Server-side tracing is global (all tables) and probabilistic, thus may not give satisfactory level of debugging.
Programmatically it's pretty simple to achieve and coupled with a good logging framework (LogBack for Java), you'll even have dynamic logging on production without having to redeploy client code. I have implemented it in Achilles very easily by wrapping over the Regular/Bound/Simple statements of Java driver and display the bound values at runtime : https://github.com/doanduyhai/Achilles/wiki/Statements-Logging-and-Tracing#dynamic-statements-logging On Mon, Nov 10, 2014 at 3:52 PM, Johnny Miller <johnny.p.mil...@gmail.com> wrote: > Be cautious enabling query tracing. Great tool for dev/testing/diagnosing > etc.. - but it does persist data to the system_traces keyspace with a TTL > of 24 hours and will, as a consequence, consume resources. > > http://www.datastax.com/dev/blog/advanced-request-tracing-in-cassandra-1-2 > > > On 7 Nov 2014, at 20:20, Jonathan Haddad <j...@jonhaddad.com> wrote: > > Personally I've found that using query timing + log aggregation on the > client side is more effective than trying to mess with tracing probability > in order to find a single query which has recently become a problem. I > recommend wrapping your session with something that can automatically log > the statement on a slow query, then use tracing to identify exactly what > happened. This way finding your problem is not a matter of chance. > > > > On Fri Nov 07 2014 at 9:41:38 AM Chris Lohfink <clohfin...@gmail.com> > wrote: > >> It saves a lot of information for each request thats traced so there is >> significant overhead. If you start at a low probability and move it up >> based on the load impact it will provide a lot of insight and you can >> control the cost. >> >> --- >> Chris Lohfink >> >> On Fri, Nov 7, 2014 at 11:35 AM, Jimmy Lin <y2klyf+w...@gmail.com> wrote: >> >>> is there any significant performance penalty if one turn on Cassandra >>> query tracing, through DataStax java driver (say, per every query request >>> of some trouble query)? >>> >>> More sampling seems better but then doing so may also slow down the >>> system in some other ways? >>> >>> thanks >>> >>> >>> >> >
