Re: Removing INNER JOINs

On Wed, Dec 3, 2014 at 11:23 AM, Andres Freund <andres(at)2ndquadrant(dot)com> wrote:
> Well, the planstate tree is what determines the execution, right? I
> don't see what would stop us from doing something like replacing:
> PlanState *
> ExecInitNode(Plan *node, EState *estate, int eflags)
> {
> ...
> case T_NestLoop:
> result = (PlanState *) ExecInitNestLoop((NestLoop *) node,
> estate, eflags);
> by
> case T_NestLoop:
> if (JoinCanBeSkipped(node))
> result = NonSkippedJoinNode(node);
> else
> result = (PlanState *) ExecInitNestLoop((NestLoop *) node,
> estate, eflags);
>
> Where JoinCanBeSkipped() and NonSkippedJoinNode() contain the logic
> from David's early patch where he put the logic entirely into the actual
> execution phase.

Yeah, maybe. I think there's sort of a coding principle that the plan
and planstate trees should match up one-to-one, but it's possible that
nothing breaks if they don't, or that I've misunderstood the coding
rule in the first instance.

--
Robert Haas
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