Re: [PATCH] doc: clarify pg_stat_lock.fastpath_exceeded scope

Hi,

On Sat, Jun 13, 2026 at 01:15:49PM +0900, Tatsuya Kawata wrote:
> Hi,
>
> While developing the pg_stat_lock improvement proposed in (*1), I
> noticed that the documentation of the fastpath_exceeded column in
> pg_stat_lock could be more explicit about its scope.
>
> The current documentation describes it as:
>
> Number of times a lock of this type could not be acquired via fast
> path because the fast path slot limit was exceeded. Increasing
> max_locks_per_transaction can reduce this number.
>
> This omits the fact that fast-path locking only applies to relation
> locks acquired in the weak modes (AccessShareLock, RowShareLock,
> RowExclusiveLock), so the counter is always zero for any other
> locktype.
>
> The attached patch adds a short clarification to the pg_stat_lock entry
> in monitoring.sgml.

I think that the current documentation is lacking explanation as to what the fast
path means as a whole. So I think that what we could do instead, is to explain
what fast path means (maybe around pg_lock?). Then, we could reference it in
pg_stat_lock if we feel the need.

Thoughts?

Regards,

--
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com