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From Jonathan Haddad <...@jonhaddad.com>
Subject Re: query tracing
Date Fri, 07 Nov 2014 19:20:31 GMT
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 <clohfink85@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+work@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
>>
>>
>>
>

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