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From Roshan Dawrani <roshandawr...@gmail.com>
Subject mutator.execute() timings - big variance noted - pointers needed on understanding/improving it
Date Thu, 10 Mar 2011 14:30:34 GMT
Hi,

I am in the middle of some load testing on a 1-node Cassandra setup. We are
not on very high loads yet. We have recorded the timings taken up by
mutator.execute() calls and we see this kind of variation during the test
run:

So, 25% of the times, execute() calls come back in 25 milli-seconds, but the
longer calls go upto 4 seconds.

Can someone please provide some pointers on what and where to focus on in my
Hector / Cassandra setup? We are mostly on the default Cassandra
configuration at this time - only change is the max connection pool size
(CassandraHostConfigurator.maxActive) is changed to 300 from a default of
50.

I would also like to add that the time increase is not linear - it starts
fast, goes, slow, very slow, and becomes faster again.

------------------------
  25%     29
  50%    105
  66%    185
  70%    208
  75%    240
  80%    297
  90%    510
  95%    854
  98%   1075
  99%   1215
 100%   4442
------------------------

-- 
Roshan
Blog: http://roshandawrani.wordpress.com/
Twitter: @roshandawrani <http://twitter.com/roshandawrani>
Skype: roshandawrani

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