Re: [BUG]Invalidate relcache when setting REPLICA IDENTITY

On Thu, Nov 11, 2021 at 7:07 AM houzj(dot)fnst(at)fujitsu(dot)com
<houzj(dot)fnst(at)fujitsu(dot)com> wrote:
>
> On Wed, Nov 10, 2021 7:29 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> >
> > I don't understand the purpose of idx_b in the above test case, why is it
> > required to reproduce the problem?
> > @@ -15488,6 +15488,7 @@ relation_mark_replica_identity(Relation rel, char
> > ri_type, Oid indexOid,
> > CatalogTupleUpdate(pg_index, &pg_index_tuple->t_self, pg_index_tuple);
> > InvokeObjectPostAlterHookArg(IndexRelationId, thisIndexOid, 0,
> > InvalidOid, is_internal);
> > + CacheInvalidateRelcache(rel);
> >
> > CatalogTupleUpdate internally calls heap_update which calls
> > CacheInvalidateHeapTuple(), why is that not sufficient for invalidation?
>
> I think it's because the bug happens only when changing REPLICA IDENTITY index
> from one(idx_a) to another one(idx_b).
>

Okay, but do we need to invalidate the rel cache each time the dirty
flag is set? Can't we do it once outside the foreach index loop? I
think we can record whether to do relcache invalidation in a new
boolean variable need_rel_inval or something like that. Also, it is
better if you can add a comment on the lines of: "Invalidate the
relcache for the table so that after we commit all sessions will
refresh the table's replica identity index before attempting any
update on the table.".

--
With Regards,
Amit Kapila.