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

Robert Haas <robertmhaas@gmail.com>

From: Robert Haas <robertmhaas@gmail.com>

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

Cc: pgsql-hackers@postgresql.org

Date: 2011-10-21T20:24:12Z

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 →

Remove pg_upgrade dependency on the 'postgres' database existing in the
- 51eba98cf459 9.2.0 cited

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.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company