Re: inheritance: planning time vs children number vs column number - Mailing list pgsql-performance

From Marc Cousin
Subject Re: inheritance: planning time vs children number vs column number
Date
Msg-id 201103011639.19396.cousinmarc@gmail.com
Whole thread Raw
In response to Re: inheritance: planning time vs children number vs column number  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-performance

The Tuesday 01 March 2011 16:33:51, Tom Lane wrote :

> Marc Cousin <cousinmarc@gmail.com> writes:

> > Le mardi 01 mars 2011 07:20:19, Tom Lane a écrit :

> >> It's worth pointing out that the only reason this effect is dominating

> >> the runtime is that you don't have any statistics for these toy test

> >> tables. If you did, the cycles spent using those entries would dwarf

> >> the lookup costs, I think. So it's hard to get excited about doing

> >> anything based on this test case --- it's likely the bottleneck would be

> >> somewhere else entirely if you'd bothered to load up some data.

> >

> > Yes, for the same test case, with a bit of data in every partition and

> > statistics up to date, planning time goes from 20 seconds to 125ms for

> > the 600 children/1000 columns case. Which is of course more than

> > acceptable.

>

> [ scratches head ... ] Actually, I was expecting the runtime to go up

> not down. Maybe there's something else strange going on here.

>

> regards, tom lane


Then, what can I do to help ?

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