Re: checking rd_rules in RelationBuildDesc

2022-11-25 Thread Ted Yu
On Fri, Nov 25, 2022 at 8:17 AM Tom Lane  wrote:

> Ted Yu  writes:
> > I wonder if we should check relation->rd_rules after the call
> > to RelationBuildRuleLock().
>
> That patch is both pointless and wrong.  There is some
> value in updating relhasrules in the catalog, so that future
> relcache loads don't uselessly call RelationBuildRuleLock;
> but we certainly can't try to do so right there.  That being
> the case, making the relcache be out of sync with what's on
> disk cannot have any good consequences.  The most likely
> effect is that it would block later logic from fixing things
> correctly.  There is logic in VACUUM to clean out obsolete
> relhasrules flags (see vac_update_relstats), but I suspect
> that would no longer work properly if we did this.
>
> regards, tom lane
>
Hi,
Thanks for evaluating the patch.

The change was originating from what we have in
RelationCacheInitializePhase3():

if (relation->rd_rel->relhasrules && relation->rd_rules ==
NULL)
{
RelationBuildRuleLock(relation);
if (relation->rd_rules == NULL)
relation->rd_rel->relhasrules = false;

FYI


Re: checking rd_rules in RelationBuildDesc

2022-11-25 Thread Tom Lane
Ted Yu  writes:
> I wonder if we should check relation->rd_rules after the call
> to RelationBuildRuleLock().

That patch is both pointless and wrong.  There is some
value in updating relhasrules in the catalog, so that future
relcache loads don't uselessly call RelationBuildRuleLock;
but we certainly can't try to do so right there.  That being
the case, making the relcache be out of sync with what's on
disk cannot have any good consequences.  The most likely
effect is that it would block later logic from fixing things
correctly.  There is logic in VACUUM to clean out obsolete
relhasrules flags (see vac_update_relstats), but I suspect
that would no longer work properly if we did this.

regards, tom lane