Renoy, Out of curiosity, which kernel version are your nodes running?
You may find this old message on the mailing list helpful: http://mail-archives.apache.org/mod_mbox/cassandra-user/201602.mbox/%3CCAA=6j0-0vabfan3djfatoxyjwwehpdie67v2wm_u5kaqoro...@mail.gmail.com%3E On Wed, Aug 1, 2018 at 5:38 PM, Elliott Sims <elli...@backblaze.com> wrote: > You might have more luck trying to analyze at the Java level, either via a > (Java) stack dump and the "ttop" tool from Swiss Java Knife, or Cassandra > tools like "nodetool tpstats" > > On Wed, Aug 1, 2018 at 2:08 AM, nokia ceph <nokiacephus...@gmail.com> > wrote: > >> Hi, >> >> i'm having a 5 node cluster with cassandra 3.0.13. >> >> i could see the cassandra process has too many threads. >> >> *# pstree -p `pgrep java` | wc -l* >> *453* >> >> And almost all of those threads are in *sleeping* state and wait at >> *# cat /proc/166022/task/1698913/wchan* >> *futex_wait_queue_me* >> >> Some more info: >> *# strace -e trace=all -p 166022* >> *strace: Process 166022 attached* >> *futex(0x7efc24aeb9d0, FUTEX_WAIT, 166023, NULL* >> >> # cat /proc/166022/stack >> [<ffffffff810f5126>] futex_wait_queue_me+0xc6/0x130 >> [<ffffffff810f5deb>] futex_wait+0x17b/0x280 >> [<ffffffff810f7b26>] do_futex+0x106/0x5a0 >> [<ffffffff810f8040>] SyS_futex+0x80/0x180 >> [<ffffffff816b4fc9>] system_call_fastpath+0x16/0x1b >> [<ffffffffffffffff>] 0xffffffffffffffff >> >> >> What is the reason cassandra is having these many threads? is it the >> normal behavior of cassandra? Is there a way to reduce this thread count? >> will there be any performance impact because of this (our platform experts >> suspects so)? >> >> Regards, >> Renoy Paulose >> >> > -- *Joshua Galbraith *| Lead Software Engineer | New Relic
