cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Elliott Sims <elli...@backblaze.com>
Subject Re: Too many Cassandra threads waiting!!!
Date Thu, 02 Aug 2018 00:38:44 GMT
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 <nokiacephusers@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
>
>

Mime
View raw message