Re: WIP: cross column correlation ...

> I think there would be value in giving the DBA an easier way to see
> which tables are hot, but I am really leery about the idea of trying
> to feed that directly into the query planner.  I think this is one of
> those cases where we let people tune it manually for starters, and
> then wait for feedback.  Eventually someone will say "oh, I never tune
> that by hand any more, ever since I wrote this script which does the
> following computation... and I just run it out cron".  And then we
> will get out the party hats.  But we will never get the experience we
> need to say what that auto-tuning algorithm will be unless we first
> provide the knob for someone to fiddle with manually.

I'm not disagreeing with that.  I'm saying "first, we give DBAs a way to
see which tables are currently hot".  Such a feature has multiple
benefits, making it worth the overhead and/or coding effort.

Whether we're shooting for autotuning or manual tuning, it starts with
having the data.


-- 
                                  -- Josh Berkus
                                     PostgreSQL Experts Inc.
                                     http://www.pgexperts.com