Re: Problems with hash join over nested loop

On 10/29/13 11:45 AM, Tom Lane wrote:
> Jim Nasby <jnasby(at)enova(dot)com> writes:
>> I'm also wondering if it's time to raise those limits.
>
> Yeah, possibly. The current default values were set on machines much
> smaller/slower than most current hardware.
>
> I think also that the collapse limits were invented mainly to keep people
> out of GEQO's clutches, but we've made some significant fixes in GEQO
> since then. Maybe the real answer is to make the default collapse limits
> much higher, and lower geqo_threshold to whatever we think the threshold
> of pain is for applying the regular planner.

In my test case geqo does seem to do a good job. I'll see if I can get some data on how number of relations affects planning time... I don't get much of a warm fuzzy about lowering geqo...
--
Jim Nasby, Lead Data Architect (512) 569-9461