Re: Assertion failure in SnapBuildInitialSnapshot()

On Tue, Jan 31, 2023 at 3:59 PM Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> wrote:
>
> On Tue, Jan 31, 2023 at 3:56 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> >
> > On Tue, Jan 31, 2023 at 11:12 AM Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> wrote:
> > >
> > > On Mon, Jan 30, 2023 at 9:41 PM Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> wrote:
> > >
> > > I've attached patches for HEAD and backbranches. Please review them.
> > >
> >
> > Shall we add a comment like the one below in
> > ReplicationSlotsComputeRequiredXmin()?
> > diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c
> > index f286918f69..e28d48bca7 100644
> > --- a/src/backend/replication/slot.c
> > +++ b/src/backend/replication/slot.c
> > @@ -840,6 +840,13 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked)
> >
> > Assert(ReplicationSlotCtl != NULL);
> >
> > + /*
> > + * It is possible that by the time we compute the agg_xmin
> > here and before
> > + * updating replication_slot_xmin, the CreateInitDecodingContext() will
> > + * compute and update replication_slot_xmin. So, we need to acquire
> > + * ProcArrayLock here to avoid retreating the value of
> > replication_slot_xmin.
> > + */
> > +
>
> Agreed. It looks good to me.

Attached updated patches.

Regards,

--
Masahiko Sawada
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