Re: More vacuum stats

Magnus Hagander <magnus(at)hagander(dot)net> writes:
> I noticed that we were already tracking the information about when an
> autovacuum worker was last started in a database, but this information
> was not exposed. The attached patch puts this column in
> pg_stat_database.

> Was there any particular reason why this wasn't exposed before that
> I've missed, making this a bad addition? :-)

I think that's an implementation detail. If we expose it then we'll
be forced to track it forevermore, regardless of whether the AV launcher
actually needs it in the future. (In particular, the assumption that
this is tracked per-database and not per-something-else seems like an
artifact of the current AV launching algorithm.)

So I'd like to see a positive argument why this is important for users
to know, rather than merely "we should expose every conceivable detail
by default". Why wouldn't a user care more about last AV time for a
specific table, which we already do expose?

regards, tom lane