Re: speeding up planning with partitions

Amit Langote <Langote_Amit_f8@lab.ntt.co.jp> writes:
> [ v22 patch set ]

I started to look at this, and immediately choked on the 0001 patch:

        if (childpruned ||
            !apply_child_basequals(root, rel, childrel, childRTE, appinfo) ||
            relation_excluded_by_constraints(root, childrel, childRTE))
        {

Frankly, that code is just horrid.  Having a function with side effects
in an if-test is questionable at the best of times, and having it be
the second of three conditions (which the third condition silently depends
on) is unreadable and unmaintainable.

I think the existing code here is considerably cleaner than what this
patch proposes.

I suppose you are doing this because you intend to jam some additional
cleanup code into the successfully-pruned-it code path, but if said
code is really too bulky to have multiple copies of, couldn't you
put it into a subroutine?  You're not going to be able to get to only
one copy of such cleanup anyhow, because there is another early-exit
further down, for the case where set_rel_size detects dummy-ness.

            regards, tom lane