What Cassandra version? CMS or G1? What are your timeouts set to? "GC activity" - Even if there isn't a lot of activity per se maybe there is a single long pause happening. I have seen large partitions cause lots of allocation fast.
Looking at SSTable Levels in nodetool cfstats can help, look at it for all your tables. Don't recommend switching to STCS until you know more. You end up with massive compaction that takes a long time to settle down. On Tue, Feb 14, 2017 at 5:50 PM, John Sanda <john.sa...@gmail.com> wrote: > I have a table that uses LCS and has wound up with partitions upwards of > 700 MB. I am seeing lots of the large partition warnings. Client requests > are subsequently failing. The driver is not reporting timeout exception, > just NoHostAvailableExceptions (in the logs I have reviewed so far). I know > that I need to redesign the table to avoid such large partitions. What > specifically goes wrong that results in the instability I am seeing? Or put > another way, what issues will compacting really large partitions cause? > Initially I thought that there was high GC activity, but after closer > inspection that does not really seem to happening. And most of the failures > I am seeing are on reads, but for an entirely different table. Lastly, does > anyone has anyone had success to switching to STCS in this situation as a > work around? > > Thanks > > - John > -- Dan Kinder Principal Software Engineer Turnitin – www.turnitin.com dkin...@turnitin.com
