Re: gprof SELECT COUNT(*) results - Mailing list pgsql-hackers

From Simon Riggs
Subject Re: gprof SELECT COUNT(*) results
Date
Msg-id 1133008761.2906.121.camel@localhost.localdomain
Whole thread Raw
In response to Re: gprof SELECT COUNT(*) results  ("Qingqing Zhou" <zhouqq@cs.toronto.edu>)
Responses Re: gprof SELECT COUNT(*) results
List pgsql-hackers
On Sat, 2005-11-26 at 03:13 -0500, Qingqing Zhou wrote:
> "Tom Lane" <tgl@sss.pgh.pa.us> wrote
> >
> > I plan to take a look at it soon.
> >
> 
> "Stand corrected"[Merlin]! In-memory "SELECT COUNT(*)" doubles the 
> performance due to my test.
> 
> - before -
> 1.56 s
> 
> - now -
> 0.72 s
> 

...and for emphasis: this optimization of SeqScans is not possible with
any other database system, so its a big win for PostgreSQL.

Best Regards, Simon Riggs



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