Re: No hash join across partitioned tables?

Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> In going back through emails I had marked as possibly needing another
> look before 9.0 is released, I came across this issue again. As I
> understand it, analyze (or analyse) now collects statistics for both
> the parent individually, and for the parent and its children together.
> However, as I further understand it, autovacuum won't actually fire
> off an analyze unless there's enough activity on the parent table
> considered individually to warrant it. So if you have an empty parent
> and a bunch of children with data in it, your stats will still stink,
> unless you analyze by hand.

Check.

> Assuming my understanding of the problem is correct, we could:

> (a) fix it,
> (b) document that you should consider periodic manual analyze commands
> in this situation, or
> (c) do nothing.

> Thoughts?

The objections to (a) are that it might result in excessive ANALYZE work
if not done intelligently, and that we haven't got a patch ready anyway.
I would have liked to get to this for 9.0 but I feel it's a bit late
now.

regards, tom lane