> $client->batch_mutate($mutations, > cassandra_ConsistencyLevel::QUORUM);
Btw, what are the mutations? Are you doing something like inserting both very small values and very large ones? In any case: My main reason to butt back into this thread is that under normal circumstances you shouldn't be seeing very frequent long-term pauses due to GC. If your workload is not doing something particularly unusual, even if you do end up triggering a GC fallback to full stop-the-world GC, it should happen comparatively infrequently and you should be seeing many CMS cycles in between each such long pause. That's why I asked about the frequency. If you're doing a long-term stress test and seeing a 30 second pause once per week, that's a lot more likely to be "normal" for your workload than if you're seeing it happen once ever three minutes. The issue is that if you want to fix your problem, one must first figure out what the problem *is*. Based on past mailing list traffic, it seems most people's problems that are seemingly "due to GC" end up being because of a too high live set size or the CMS phase triggering too late. These are fixable issues if are running into them. If all you have is a single column family with a 64 mb flush threshold and doing a bunch of insertions, and have a heap size of 5 (was it?) gig, you should not be having these issues. But stating that helps no one, which is why I'm asking for more information. (Widely extrapolating and suggesting that all Cassandra nodes will always freeze for 30 seconds every now and then is also helping no one, other than not being true.) -- / Peter Schuller
