[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Too many Cassandra threads waiting!!!


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

And almost all of those threads are in sleeping state and wait at
# cat  /proc/166022/task/1698913/wchan

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)?

Renoy  Paulose