Re: Release SPI plans for referential integrity with DISCARD ALL

On Wed, Mar 10, 2021 at 1:49 PM yuzuko <yuzukohosoya(at)gmail(dot)com> wrote:
>
> Hello,
>
> I thought about this suggestion again.
>
> Amit's patch suggested in the thread [1] can eliminate SPI plans from
> INSERT/UPDATE triggers, so our memory pressure issue would be solved.
> But as far as I can see that thread, Amit's patch doesn't cover DELETE case.
> It is not a common case, but there is a risk of pressing memory
> capacity extremely.
> Considering that, this suggestion might still have good value as Corey
> said before.
>
> I improved a patch according to Peter's following comment :
> > but I think the
> > solution of dropping all cached plans as part of DISCARD ALL seems a bit
> > too extreme of a solution. In the context of connection pooling,
> > getting a new session with pre-cached plans seems like a good thing, and
> > this change could potentially have a performance impact without a
> > practical way to opt out.
>
> In a new patch, I separated discarding SPI Plan caches for RI from DISCARD ALL
> and added a new option "RIPLANS" to DISCARD command to do that. Also a new
> function, ResetRIPlanCache() which clears SPI plan caches is called by
> DISCARD ALL
> or DISCARD RIPLANS. The amount of modification is small and this option can be
> removed instantly when it is no longer needed, so I think we can use
> this patch as
> a provisional solution.
>
> Any thoughts?

The patch does not apply on Head anymore, could you rebase and post a
patch. I'm changing the status to "Waiting for Author".

Regards,
Vignesh