RE: Fix race in ReplicationSlotRelease for ephemeral slots

On Tuesday, June 16, 2026 5:36 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>
> On Tue, Jun 16, 2026 at 2:24 PM Zhijie Hou (Fujitsu) <houzj(dot)fnst(at)fujitsu(dot)com>
> wrote:
> >
> >
> > I have one minor comment for the 0001 patch.
> >
> > + NameData slot_name = {0};
> > ...
> > SpinLockAcquire(&local_slot->mutex);
> > synced_slot = local_slot->in_use &&
> > local_slot->data.synced;
> > + if (synced_slot)
> > + slot_name = local_slot->data.name;
> > SpinLockRelease(&local_slot->mutex);
> >
> > We can defer assigning slot_name until after we pass the existing
> > (synced_slot) check. Since it's a synced slot, no other process can
> > change it at that point, and we can also skip initializing slot_name.
> > (Please refer to the attached patch for suggested changes)
> >
>
> + if (dropped)
> + ereport(LOG,
> + errmsg("dropped replication slot \"%s\" of database with OID %u",
> + NameStr(slot_name),
> + slot_database));
>
> Can we avoid the if (dropped) check by placing this LOG message immediately
> after dropping the slot under synced slot check?

I think we can do that. I'm attaching the new patches for all supported
branches, incorporating both my and Amit's comments. I hope this helps move the
fix forward.

I also confirmed that the fix works on all supported branches.

Best Regards,
Hou zj