Skip site navigation (1) Skip section navigation (2)

Re: Max time queries

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: "Chad Thompson" <chad(at)weblinkservices(dot)com>
Cc: "pgsql-performance" <pgsql-performance(at)postgresql(dot)org>
Subject: Re: Max time queries
Date: 2002-10-18 01:37:27
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-performance
"Chad Thompson" <chad(at)weblinkservices(dot)com> writes:
> Heres an oddity.  Why would it take more time to not find an answer than it
>  would to find one?

Because the successful query stops as soon as it's exhausted the LIMIT
(ie, after it's found the first matching combination of rows).  The
failing query has to run through the whole tables looking in vain for
a match.  Note the difference in number of rows scanned in the lower
levels of your query.

			regards, tom lane

In response to

pgsql-performance by date

Next:From: Mario WeilguniDate: 2002-10-21 06:23:33
Subject: Self-generating statistics?
Previous:From: Chad ThompsonDate: 2002-10-17 14:45:07
Subject: Max time queries

Privacy Policy | About PostgreSQL
Copyright © 1996-2017 The PostgreSQL Global Development Group