Re: Replication logging

On Mon, Jan 17, 2011 at 1:57 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Magnus Hagander <magnus(at)hagander(dot)net> writes:
>> On Mon, Jan 17, 2011 at 17:46, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>>> I think it'd make more sense just to say that replication connections
>>> are subject to the same log_connections rule as others.  An extra GUC
>>> for this is surely overkill.
>
>> I thought so, but Robert didn't agree. And given that things are the
>> way they are, clearly somebody else didn't agree as well - though I've
>> been unable to locate the original discussion if there was one.
>
> The existing behavior dates from here:
> http://archives.postgresql.org/pgsql-committers/2010-03/msg00245.php
>
> As best I can tell there was no preceding discussion, just Simon
> unilaterally deciding that this logging was required for debugging
> purposes.  (There is a followup thread in -hackers arguing about the
> message wording, but nobody questioned whether it should come out
> unconditionally.)
>
> I'm of the opinion that the correct way of "lowering in later releases"
> is to make the messages obey Log_connections.  The "needed for debug"
> argument seems mighty weak to me even for the time, and surely falls
> down now.

On a busy system, you could have a pretty high rate of messages
spewing forth for regular connections - that's a lot to wade through
if all you really want to see are the replication connections, which
should be much lower volume. But I guess now that we have
pg_stat_replication it's a little easier to see the status of
replication anyway. On the whole I've found the default setting here
very pleasant, so I'm reluctant to change it, but it sounds like I
might be out-voted.

--
Robert Haas
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