Horton

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

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: pgsql-hackers@postgresql.org
Date: 2011-10-23T03:14:48Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Remove pg_upgrade dependency on the 'postgres' database existing in the

Robert Haas <robertmhaas@gmail.com> writes:
> On Fri, Oct 21, 2011 at 3:55 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Robert Haas <robertmhaas@gmail.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.

Oh, the ExecProject calls are coming from advance_aggregates().
Move along, nothing to see here ...

			regards, tom lane