Re: inheritance: planning time vs children number vs column number

Marc Cousin <cousinmarc(at)gmail(dot)com> writes:
> Le mardi 01 mars 2011 07:20:19, Tom Lane a crit :
>> 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