Re: [PERFORM] How to read query plan

Tom Lane wrote:

>I wrote:
>
>
>>Since ExecProject operations within a nest of joins are going to be
>>dealing entirely with Vars, I wonder if we couldn't speed matters up
>>by having a short-circuit case for a projection that is only Vars.
>>Essentially it would be a lot like execJunk.c, except able to cope
>>with two input tuples.  Using heap_deformtuple instead of retail
>>extraction of fields would eliminate the O(N^2) penalty for wide tuples.
>>
>>
>
>Actually, we already had a pending patch (from Atsushi Ogawa) that
>eliminates that particular O(N^2) behavior in another way.  After
>applying it, I get about a factor-of-4 reduction in the runtime for
>Miroslav's example.
>
>
Is there a chance we will see this patch in the 8.0.2 release? And when
can we expect this release?

>ExecEvalVar and associated routines are still a pretty good fraction of
>the runtime, so it might still be worth doing something like the above,
>but it'd probably be just a marginal win instead of a big win.
>
>            regards, tom lane
>
>
Miroslav