From: Justin Pryzby <pryzby@telsasoft.com>
To: James Pang (chaolpan) <chaolpan@cisco.com>
Cc: pgsql-performance@lists.postgresql.org
Subject: Re: postgres backend process hang on " D " state
Date: Sun, 29 May 2022 10:01:57 -0500
Message-ID: <20220529150157.GM19626@telsasoft.com> (raw)
In-Reply-To: <PH0PR11MB5191521AF97E422D288DB9DBD6DA9@PH0PR11MB5191.namprd11.prod.outlook.com>
References: <PH0PR11MB5191521AF97E422D288DB9DBD6DA9@PH0PR11MB5191.namprd11.prod.outlook.com>
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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To: pgsql-performance@postgresql.org
Cc: pryzby@telsasoft.com, chaolpan@cisco.com, pgsql-performance@lists.postgresql.org
Subject: Re: postgres backend process hang on " D " state
In-Reply-To: <20220529150157.GM19626@telsasoft.com>
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