Re: scalability bottlenecks with (many) partitions (and more)

On Wed, 4 Sept 2024 at 03:06, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>
> On Mon, Sep 2, 2024 at 1:46 PM Tomas Vondra <tomas(at)vondra(dot)me> wrote:
> > But say we add a GUC and set it to -1 by default, in which case it just
> > inherits the max_locks_per_transaction value. And then also provide some
> > basic metric about this fast-path cache, so that people can tune this?
>
> All things being equal, I would prefer not to add another GUC for
> this, but we might need it.

I think driving the array size from max_locks_per_transaction is a
good idea (rounded up to the next multiple of 16?). If someone comes
along one day and shows us a compelling case where some backend needs
more than its fair share of locks and performance is bad because of
that, then maybe we can consider adding a GUC then. Certainly, it's
much easier to add a GUC later if someone convinces us that it's a
good idea than it is to add it now and try to take it away in the
future if we realise it's not useful enough to keep.

David