Re: Mutex error 22 - Postgres version 14

Thanks for the update . It went to my spam folder and missed your earlier inputs.

Here is the detailed information of the error.

There is an additional error "Error WriteLocking RWLock!35" along with Mutex 22 error in the logfile.

A description of what you are trying to achieve and what results you expect.
 Encountered Mutex 22 error with Postgres defunct processes in Postgres version 14 database. Its an active/standby setup with repmgr and pgbouncer.

The database went into hung state with Postgres defunct process and we had to restart the server to make database operational again .
I have pasted the error messages found in postgresql.log.


The EXACT PostgreSQL version you are running
PostgreSQL 14.1 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 8.4.1 20200928 (Red Hat 8.4.1-1), 64-bit

How you installed PostgreSQL

https://www.postgresql.org/

Changes made to the settings in the postgresql.conf file: see Server Configuration for a quick way to list them all.
max_wal_size = 1GB
min_wal_size = 80MB

shared_buffers = 10GB

Operating system and version
Linux 4.18.0-305.12.1.el8_4.x86_64
x86_64 x86_64 x86_64 GNU/Linux

For questions about any kind of error:
What you were doing when the error happened / how to cause the error.
The database went into hung state with below errors in the postgresql.log
2023-01-24 10:29:45.399 PST [912001] LOG:  PID 0 in cancel request did not match any process
Error WriteLocking RWLock!35
2023-01-24 10:31:21.084 PST [9677] WARNING:  worker took too long to start; canceled
2023-01-24 10:32:21.143 PST [9677] WARNING:  worker took too long to start; canceled
2023-01-24 10:33:21.171 PST [9677] WARNING:  worker took too long to start; canceled
2023-01-24 10:34:21.305 PST [9677] WARNING:  worker took too long to start; canceled
2023-01-24 10:35:21.357 PST [9677] WARNING:  worker took too long to start; canceled
2023-01-24 10:36:21.417 PST [9677] WARNING:  worker took too long to start; canceled
2023-01-24 10:37:21.468 PST [9677] WARNING:  worker took too long to start; canceled
2023-01-24 10:38:21.532 PST [9677] WARNING:  worker took too long to start; canceled
Also we have noticed defunct processes from Postgres. We had to restart the Server to make the database operational.

What program you're using to connect to PostgreSQL
It's active /passive standby setup with repmgr to maintain the cluster and pgbouncer to connect to the Postgres dtaabase.
Version - pgbouncer-1.15.0
Is there anything remotely unusual in the PostgreSQL server logs?
No abnormal errors noticed in the server log.

Regards,

PS