Re: No hash join across partitioned tables?

Bruce Momjian <bruce@momjian.us>

From: Bruce Momjian <bruce@momjian.us>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Robert Haas <robertmhaas@gmail.com>, Kris Jurka <books@ejurka.com>, pgsql-performance@postgresql.org
Date: 2010-07-02T03:00:00Z
Lists: pgsql-hackers, pgsql-performance
Tom Lane wrote:
> Robert Haas <robertmhaas@gmail.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.

What do we want to do about the above issue?

-- 
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + None of us is going to be here forever. +