Re: Maximum amount of pg_locks

Actualisation script maximo plus??

mie., 28 ian. 2026, 22:12 Tim Herren <tim(dot)herren(at)protonmail(dot)ch> a scris:

> Hi
>
> I'm trying to wrap my head around the way the calculation for the maximum
> amount of locks works in postgres 16.11
> I already came to the understanding that the maximum amount of locks are
> not on a transaction basis, but rather influenced by the setting
> "max_locks_per_transaction" and the "max_connections".
> I'm saying influenced rather than calculated because on my server a simple
> multiplication of those two values, set at 512 and 180 respectively gives
> 92160.
>
> Yet I regularly observe around 119k locks during my backup using "pg_dump
> -Fc".
>
> postgres=# SELECT
> locktype,
> mode,
> count(*)
> FROM pg_locks
> GROUP BY 1, 2
> ORDER BY 3 DESC;
> locktype | mode | count
> ------------+-----------------+--------
> relation | AccessShareLock | 119948
> virtualxid | ExclusiveLock | 2
> (2 rows)
>
> The database I'm backing up at that time contains 242 schemas and each has
> around 500 relations (a mix of tables and sequences).
> So that matches pretty well.
>
> I've verified that my configured setting is enough in the sense that I get
> a usable backup and my database remains operational during the backup
> period. Non the less I would like to understand where that difference comes
> from and how close to the "actual limit" I am.
> Please let me know if this needs more information.
>
> Thanks
>