Re: speeding up planning with partitions

Hi Justin,

Thanks for checking.

On Sat, Feb 23, 2019 at 1:59 AM Justin Pryzby <pryzby(at)telsasoft(dot)com> wrote:
>
> On Fri, Feb 22, 2019 at 09:45:38PM +0900, Amit Langote wrote:
> > I have updated the inheritance expansion patch.
> >
> > Patch 0001 rewrites optimizer/utils/inherit.c, so that it allows
>
> Thanks for your continued work on this.
>
> I applied v23 patch and imported one of our customers' schema, and ran explain
> on a table with 210 partitions. With patch applied there are 10x fewer system
> calls, as intended.
>
> with patch:
> 173 pread64
> 76 lseek
> 47 open
> 38 brk
>
> without patch:
> 1276 lseek
> 693 pread64
> 647 open
> 594 brk

OK, great. I guess you were running SELECT? Just in case you missed,
the patch to improve UPDATE/DELETE scalability is no longer part of
this patch series.

> > + if (IS_SIMPLE_REL(rel1) && child_rel1 == NULL)
> > + child_rel1 = build_dummy_partition_rel(root, rel1, baserel1,
> > + cnt_parts);
> > + if (IS_SIMPLE_REL(rel1) && child_rel2 == NULL)
> > + child_rel2 = build_dummy_partition_rel(root, rel2, baserel2,
> > + cnt_parts);
>
> Should 2nd "if" say IS_SIMPLE_REL(rel2) ?

Good catch, fixed. Apparently not guarded by a test, but I haven't
bothered to add new tests with this patch series.

Please find attached updated patches. I've made a few updates in last
couple of hours such as improving comments, fixing a few thinkos in
inheritance_planner changes, etc.

Thanks,
Amit