Re: So, is COUNT(*) fast now?

On Fri, Oct 21, 2011 at 3:55 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Robert Haas <robertmhaas(at)gmail(dot)com> writes:
>> Anyhow, here's the scoop.  On my desktop machine running F14, running
>> SELECT sum(1) FROM pgbench_accounts in a tight loop, 60 s worth of
>> oprofile data:
>
>> 176830   13.0801  postgres                 postgres                 ExecProject
>
> Hm, that's weird.  In both these cases, I'd have expected that
> ExecProject would get optimized away thanks to selection of a physical
> tlist for the scan node.  Wonder if that got broken ...

If it did, it looks like it wasn't recent. I set up the same test
case on my MacBook using REL9_1_STABLE and REL9_0_STABLE and set a
breakpoint on ExecProject(). Both back-branches appear to also call
ExecProject() for every tuple.

--
Robert Haas
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