Re: repeated decoding of prepared transactions

On Thu, Feb 25, 2021 at 5:04 PM vignesh C <vignesh21(at)gmail(dot)com> wrote:
>
> On Wed, Feb 24, 2021 at 5:06 PM Ajin Cherian <itsajin(at)gmail(dot)com> wrote:
> >
> > On Wed, Feb 24, 2021 at 4:48 PM Ajin Cherian <itsajin(at)gmail(dot)com> wrote:
> >
> > > I plan to split this into two patches next. But do review and let me
> > > know if you have any comments.
> >
> > Attaching an updated patch-set with the changes for
> > snapshot_was_exported_at_lsn separated out from the changes for the
> > APIs pg_create_logical_replication_slot() and
> > pg_logical_slot_get_changes(). Along with a rebase that takes in a few
> > more commits since my last patch.
>
> One observation while verifying the patch I noticed that most of
> ReplicationSlotPersistentData structure members are displayed in
> pg_replication_slots, but I did not see snapshot_was_exported_at_lsn
> being displayed. Is this intentional? If not intentional we can
> include snapshot_was_exported_at_lsn in pg_replication_slots.
>

On thinking about this point, I feel we don't need this new parameter
in the view because I am not able to see how it is of any use to the
user. Over time, corresponding to that LSN there won't be any WAL
record or maybe WAL would be overwritten. I think this is primarily
for our internal use so let's not expose it. I intend to remove it
from the patch unless you have some reason for exposing this to the
user.

--
With Regards,
Amit Kapila.