Re: a lot of session wait on lock relation

Laurenz Albe <laurenz.albe@cybertec.at>

From: Laurenz Albe <laurenz.albe@cybertec.at>
To: James Pang <jamespang886@gmail.com>, pgsql-performance@lists.postgresql.org
Date: 2025-05-15T12:08:05Z
Lists: pgsql-performance
On Thu, 2025-05-15 at 16:27 +0800, James Pang wrote:
> PGv 15.10,  many session coming in doing "insert into tablexxx values...." in parallel,
> this is a range partition tables, total 12 partitions plus one default partition,
> only three btree indexes, no others constraints ,no foreign key. but we see hundreds
> of session waiting on "lock:relation", why inserts into partition table cause "relation lock" ?

Something else does; use the pg_blocking_pids() function with the process ID of
a blocked backend to find out who is holding the lock.

If you have hundreds of sessions, you are allowing to many connections.

Yours,
Laurenz Albe