Re: add log messages when replication slots become active and inactive (was Re: Is it worth adding ReplicationSlot active_pid to ReplicationSlotPersistentData?)

On Tue, Nov 14, 2023 at 4:50 AM Peter Smith <smithpb2250@gmail.com> wrote:
>
> Here are some review comments for patch v13-0001.

Thanks.

> ======
> doc/src/sgml/config.sgml
>
> 1.
>
> Should that also mention about walsender?
>
> e.g.
> "and slot acquisition/release" ==> "and <literal>walsender</literal>
> slot acquisition/release"

Changed.

> 2a.
> Instead of calling SlotIsLogical() and then again calling
> SlotIsPhysical(), it might be better to assign this one time to a
> local variable.
>
> 2b.
> IMO it is better to continue using variable 's' here instead of
> 'MyReplicationSlot'. Code is not only shorter but is also consistent
> with the rest of the function which never uses MyReplicationSlot, even
> in the places where it could have.
>
> SUGGESTION (for #2a and #2b)
> is_logical = SlotIsLogical(s);
> if (is_logical)
>   pgstat_acquire_replslot(s);
>
> if (am_walsender)
>   ereport(log_replication_commands ? LOG : DEBUG1,
>     errmsg_internal("acquired %s replication slot \"%s\"",
>       is_logical ? "logical" : "physical", NameStr(s->data.name)));

Use of a separate variable isn't good IMO, I used SlotIsLogical(s); directly.

> 3a.
> Notice 'MyReplicationSlot' is already assigned to the local 'slot'
> variable, so IMO it is better if this new code also uses that 'slot'
> variable for consistency with the rest of the function.
>
> 3b.
> Consider flipping the flag to be 'is_logical' instead of
> 'is_physical', so the ereport substitution will match the other
> ReplicationSlotAcquirecode suggested above (#2a).
>
> SUGGESTION (For #3a and #3b)
> if (am_walsender)
> {
>   slotname = pstrdup(NameStr(slot->data.name));
>   is_logical = SlotIsLogical(slot);
> }

Done.

PSA v14 patch.

--
Bharath Rupireddy
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com