Threads_cached is ZERO

MySQL & MariaDB Percona XtraDB Cluster 5.x
1

Hi
I have 6 nodes of Percona XtraDB Cluster with version
Server version: 5.6.19-67.0-56 Percona XtraDB Cluster (GPL), Release 25.6, wsrep_25.6.r4111

i noticed that there is no cached threads

| Threads_cached | 0 |
| Threads_connected | 1366 |
| Threads_created | 3916 |
| Threads_running | 1

in config thread_cache_size = 1024

2

Hi,

I’ve noticed the same thing. Sometimes restarting mysql or whole server “fixes” thread cache, but not always.
Any ideas how to debug why this is happening ?

mysqladmin -r -i 3 ext | grep Threads_created
Shows that threads are created all the time.

(Percona-XtraDB-Cluster-galera-3-3.6-1.3190.rhel6.x86_64
Percona-XtraDB-Cluster-server-56-5.6.19-25.6.824.el6.x86_64)

Is thread_cache_size= and one-thread-per-connection supported or is it better to try w/pool-of-threads ?

-Jarno