well. i checked it now. we have some stw collections from 100 to 200ms every 5 to 60 seconds. i am not sure whether the blocked threads are related to that but anyway these pauses are too long for low latency applications.
so i wil check gc tuning first and will check afterwards whether the blocked threads still exist afterwards. On Mon, 2017-03-20 at 08:55 +0100, benjamin roth wrote: Did you check STW GCs? You can do that with 'nodetool gcstats', by looking at the gc.log or observing GC related JMX metrics. 2017-03-20 8:52 GMT+01:00 Roland Otta <roland.o...@willhaben.at<mailto:roland.o...@willhaben.at>>: we have a datacenter which is currently used exlusively for spark batch jobs. in case batch jobs are running against that environment we can see very high peaks in blocked native transport requests (up to 10k / minute). i am concerned because i guess that will slow other queries (in case other applications are going to use that dc as well). i already tried increasing native_transport_max_threads + concurrent_reads without success. during the jobs i cant find any resource limitiations on my hardware (iops, disk usage, cpu, ... is fine). am i missing something? any suggestions how to cope with that? br// roland
