| From: | Justin Pryzby <pryzby(at)telsasoft(dot)com> |
|---|---|
| To: | "James Pang (chaolpan)" <chaolpan(at)cisco(dot)com> |
| Cc: | pgsql-performance(at)lists(dot)postgresql(dot)org |
| Subject: | Re: postgres backend process hang on " D " state |
| Date: | 2022-05-29 15:01:57 |
| Message-ID: | 20220529150157.GM19626@telsasoft.com |
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| Lists: | pgsql-performance |
On Sun, May 29, 2022 at 01:20:12PM +0000, James Pang (chaolpan) wrote:
> We have a performance test on Postgresql 13.4 on RHEL8.4 , just after connection storm in ( 952 new connections coming in 1 minute), a lot of backends start on " D " state, and when more sessions got disconnected, they do not exit successfully, instead became "defunct". No errors from postgresql.log , just after the connection storm, some pg_cron workers can not started either. The server is a Virtual machine and no IO hang (actually) IO load is very low. Could be a postgresql bug or an OS abnormal behavior?
What settings have you set ?
https://wiki.postgresql.org/wiki/Server_Configuration
What extensions do you have loaded? \dx
Send the output of SELECT * FROM pg_stat_activity either as an attachment or in
\x mode?
What is your data dir ? Is it on the VM's root filesystem or something else ?
Show the output of "mount". Are there any kernel messages in /var/log/messages
or `dmesg` ?
How many relations are in your schema ?
Are you using temp tables ?
Long-running transactions ?
--
Justin
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