Re: Resetting spilled txn statistics in pg_stat_replication

On Mon, 19 Oct 2020 at 14:24, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>
> On Mon, Oct 19, 2020 at 9:04 AM Masahiko Sawada
> <masahiko(dot)sawada(at)2ndquadrant(dot)com> wrote:
> >
> > On Thu, 15 Oct 2020 at 17:51, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> > >
> > >
> > > AFAICS, we use name data-type in many other similar stats views like
> > > pg_stat_subscription, pg_statio_all_sequences, pg_stat_user_functions,
> > > pg_stat_all_tables. So, shouldn't we consistent with those views?
> > >
> >
> > Yes, they has the name data type column but it actually comes from
> > system catalogs. For instance, here is the view definition of
> > pg_stat_subscription:
> >
> > SELECT su.oid AS subid,
> > su.subname,
> > st.pid,
> > st.relid,
> > st.received_lsn,
> > st.last_msg_send_time,
> > st.last_msg_receipt_time,
> > st.latest_end_lsn,
> > st.latest_end_time
> > FROM pg_subscription su
> > LEFT JOIN pg_stat_get_subscription(NULL::oid) st(subid, relid,
> > pid, received_lsn, last_msg_send_time, last_msg_receipt_time, latest
> > _end_lsn, latest_end_time) ON st.subid = su.oid;
> >
> > This view uses the subscription name from pg_subscription system
> > catalog. AFAICS no string data managed by the stats collector use name
> > data type. It uses char[NAMEDATALEN] instead. And since I found the
> > description about name data type in the doc, I thought it's better to
> > have it as text.
> >
>
> Okay, I see the merit of keeping slot_name as 'text' type. I was
> trying to see if we can be consistent but I guess that is not so
> straight-forward, if we go with all (stat) view definitions to
> consistently display/use 'name' datatype for strings then ideally we
> need to change at other places as well. Also, I see that
> pg_stat_wal_receiver uses slot_name as 'text', so displaying the same
> as 'name' in pg_stat_replication_slots might not be ideal.

Oh, I didn't realize pg_stat_wal_receiver uses text data type.

> So, let's
> stick with 'text' data type for slot_name which means we should
> go-ahead with the v3 version of the patch [1] posted by Shinoda-San,
> right?

Right. +1

Regards,

--
Masahiko Sawada http://www.2ndQuadrant.com/
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