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

fn;quoted-printable:Miroslav =C5=A0ulc
org:StartNet s.r.o.
adr;quoted-printable;quoted-printable:;;Vrchlick=C3=A9ho 161/5;Praha 5;;150 00;=C4=8Cesk=C3=A1 republika
email;internet:[EMAIL PROTECTED]
tel;work:+420 257 225 602
tel;cell:+420 603 711 413

---------------------------(end of broadcast)---------------------------
TIP 2: you can get off all lists at once with the unregister command
    (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED])

Reply via email to