Re: Resetting spilled txn statistics in pg_stat_replication

On Thu, Jul 2, 2020 at 1:31 PM Masahiko Sawada <
masahiko(dot)sawada(at)2ndquadrant(dot)com> wrote:

>
>
> Thanks! Yes, I'm working on this patch while considering to send the
> stats to stats collector.
>
> I've attached PoC patch that implements a simple approach. I'd like to
> discuss how we collect the replication slot statistics in the stats
> collector before I bring the patch to completion.
>
>
I understand the patch is only in the initial stage but I just tried
testing it. Using the patch, I enabled logical replication and created two
pub/subs (sub1,sub2) for two seperate tables (t1,t2). I inserted data into
the second table (t2) such that it spills into disk.
Then when I checked the stats using the new function
pg_stat_get_replication_slots() , I see that the same stats are updated for
both the slots, when ideally it should have reflected in the second slot
alone.

postgres=# SELECT s.name, s.spill_txns, s.spill_count, s.spill_bytes
FROM pg_stat_get_replication_slots() s(name, spill_txns, spill_count,
spill_bytes);
name | spill_txns | spill_count | spill_bytes
------+------------+-------------+-------------
sub1 | 1 | 20 | 1320000000
sub2 | 1 | 20 | 1320000000
(2 rows)

I haven't debugged the issue yet, I can if you wish but just thought I'd
let you know what I found.

thanks,
Ajin Cherian
Fujitsu Australia