Re: add recovery, backup, archive, streaming etc. activity messages to server logs along with ps display

On 2021-Dec-09, Bharath Rupireddy wrote:

> On Thu, Dec 9, 2021 at 6:00 PM Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org> wrote:
> >
> > On 2021-Dec-09, Bharath Rupireddy wrote:
> >
> > > I just want to call this out: an insertion of 10 million rows in the
> > > primary generates a bunch of messages in the standby [1] within 40 sec
> > > (size of the standby server log grows by 5K).
> >
> > Hmm, that does sound excessive to me in terms of log bloat increase.
> > Remember the discussion about turning log_checkpoints on by default?
>
> The amount of LOG messages generated when the log_checkpoints GUC is
> set to on, are quite less, hardly 4 messages per-checkpoint (5min). I
> think enabling log_checkpoints is still acceptable as most of the
> hackers agreed in another thread [1] that the advantages with it are
> more and it doesn't seem to be bloating the server logs (in a day at
> max 1152 messages).

My point is that it was argued, in that thread, that setting
log_checkpoints to on by default would cause too much additional log
volume. That argument was shot down, but in this thread we're arguing
that we want five kilobytes of messages in forty seconds. That sounds
much less acceptable to me, so making it default behavior or
unconditional behavior is not going to fly very high.

> I'm not sure if it is worth having a GUC log_recovery if enabled the
> recovery messages can be emitted at LOG level otherwise DEBUG1 level.

Maybe some tunable like
log_wal_traffic = { none, medium, high }
where "none" is current behavior of no noise, "medium" gets (say) once
every 256 segments (e.g., when going from XFF to (X+1)00), "high" gets
you one message per segment.

--
Álvaro Herrera PostgreSQL Developer — https://www.EnterpriseDB.com/