Re: compute_query_id and pg_stat_statements

Greetings,

* Tom Lane (tgl(at)sss(dot)pgh(dot)pa(dot)us) wrote:
> Stephen Frost <sfrost(at)snowman(dot)net> writes:
> > * Magnus Hagander (magnus(at)hagander(dot)net) wrote:
> >> Thatäs why I suggested the three value one. Default to a mode where
> >> it's automatic, which is what the majority is going to want, but have
> >> a way to explicitly turn it on.
>
> > This is certainly fine with me too, though it seems a bit surprising to
> > me that we couldn't just figure out what the user actually wants based
> > on what's installed/running for any given combination.
>
> I'd be on board with having pg_stat_statement's pg_init function do
> something to adjust the setting, if we can figure out how to do that
> in a way that's not confusing in itself. I'm not sure though that
> the GUC engine offers a good way.

Both of the extensions are getting loaded via pg_stat_statements and
both can have pg_init functions which work together to come up with the
right answer, no?

That is- can't pg_stat_statements, when it's loaded, enable
compute_query_id if it's not already enabled, and then the pg_queryid
module simply disable it when it gets loaded in it's pg_init()? Telling
people who are using pg_queryid to have it loaded *after*
pg_stat_statements certainly seems reasonable to me, but if folks don't
like that then maybe have a tri-state which is 'auto', 'on', and 'off',
where pg_stat_statements would set it to 'on' if it's set to 'auto', but
not do anything if it starts as 'off'. pg_queryid would then set it to
'off' when it's loaded and it wouldn't matter if it's loaded before or
after.

Thanks,

Stephen