RE: Difference between count(1) and count(*)

From: Cary Millsap <cary.millsap_at_hotsos.com>
Date: Thu, 8 Jul 2004 10:16:32 -0500
Message-ID: <00c501c464fe$9079f900$6701a8c0@CVMLAP02>

I think "some reason" is that for decades people didn't know how to = measure
performance (that is, response time). How can you possibly know what's = GOING
to happen if you can't even tell what DID happen?!

Cary Millsap
Hotsos Enterprises, Ltd.
http://www.hotsos.com
* Nullius in verba *

Upcoming events:
- Performance Diagnosis 101: 7/20 Cleveland, 8/10 Boston, 9/14 San = Francisco
- SQL Optimization 101: 7/26 Washington DC, 8/16 Minneapolis, 9/20 = Hartford
- Hotsos Symposium 2005: March 6-10 Dallas - Visit www.hotsos.com for schedule details...

-----Original Message-----
From: oracle-l-bounce_at_freelists.org =
[mailto:oracle-l-bounce_at_freelists.org]
On Behalf Of ryan.gaffuri_at_comcast.net
Sent: Thursday, July 08, 2004 8:38 AM
To: oracle-l_at_freelists.org; oracle-l_at_freelists.org Cc: Tanel P=F5der
Subject: Re: Difference between count(1) and count(*)

for some reason there appears to be more B.S. associated with = performance
tuning than any other Oracle topic. People are far more likely to pull = stuff
out of their asses on performance tuning than anywhere else...=20

Original message --------------=20

> I've actually seen an "expert" optimizing the count() statement, by =
using=20
> count(null) "since null means nothing and thus is the fastest" :)=20

>=20

> But check this:=20

>=20

> SQL> select count(*) from dual;=20

>=20

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Received on Thu Jul 08 2004 - 10:14:57 CDT