Re: speeding up planning with partitions

On 2019/02/21 11:31, Amit Langote wrote:
> On 2019/02/21 0:50, Tom Lane wrote:
>> There might be parts of this work we can salvage, though. It seems
>> like the idea of postponing expand_inherited_tables() might be
>> something we could use anyway.
>
> +1. So, let's try to do things in this order:
>
> 1. Make inheritance-expansion-at-bottom case perform better now,
> addressing at least SELECT performance in PG 12, provided we manage to get
> the patches in order in time (I'll try to post the updated
> lazy-inheritance-expansion patch later this week.)

I have updated the inheritance expansion patch.

Patch 0001 rewrites optimizer/utils/inherit.c, so that it allows
inheritance expansion to be invoked from make_one_rel(). Although the
rewrite in this version of the patch is a bit different from earlier
versions, because I needed to account for the fact that
inheritance_planner (whose rewrite I'm withdrawing) will use the same
expansion code to expand target inheritance. So, the code now needs to
treat source-inheritance-expansion and target-inheritance-expansion cases
a bit differently.

I wanted to polish the code and various comments a bit more because the
rewritten expansion code looks different from earlier versions as I
mentioned above, but I needed to rush out today due to a family emergency
and won't be able to reply until Wednesday next week. Sorry.

Thanks,
Amit