Re: select count() out of memory

On 10/25/07, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Alvaro Herrera <alvherre(at)commandprompt(dot)com> writes:
> > tfinneid(at)student(dot)matnat(dot)uio(dot)no wrote:
> >> I did a test previously, where I created 1 million partitions (without
> >> data) and I checked the limits of pg, so I think it should be ok.
>
> > Clearly it's not.
>
> You couldn't have tested it too much --- even planning a query over so
> many tables would take forever, and actually executing it would surely
> have run the system out of locktable space before it even started
> scanning.
>
> The partitioning facility is designed for partition counts in the tens,
> or maybe hundreds at the most.

I've had good results well into the hundreds, but after about 400 or
so, things start to get a bit wonky.