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 > >
