From: | "Pierre C" <lists(at)peufeu(dot)com> |
---|---|
To: | "pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org>, "Neil Whelchel" <neil(dot)whelchel(at)gmail(dot)com> |
Subject: | Re: Slow count(*) again... |
Date: | 2010-10-12 21:35:01 |
Message-ID: | op.vkhfkn1yeorkce@apollo13 |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers pgsql-performance |
> suggest that 99% instances of the "select count(*)" idiom are probably
>> bad use of the SQL language.
Well, suppose you paginate results. If the user sees that the search query
returns 500 pages, there are two options :
- you're google, and your sorting algorithms are so good that the answer
the user wants is in the first page
- or the user will refine his search by entering more keywords tu get a
manageable result set
So, in both cases, the count(*) was useless anyway. And the slowest ones
are the most useless, since the user will immediatey discard the result
and refine his query.
If your full text search is slow, try Xapian or Lucene.
From | Date | Subject | |
---|---|---|---|
Next Message | Kevin Grittner | 2010-10-12 21:51:06 | Re: SQL command to edit postgresql.conf, with comments |
Previous Message | Darren Duncan | 2010-10-12 21:33:37 | Re: SQL command to edit postgresql.conf, with comments |
From | Date | Subject | |
---|---|---|---|
Next Message | Neil Whelchel | 2010-10-12 22:21:31 | Re: Slow count(*) again... |
Previous Message | Tom Lane | 2010-10-12 21:22:14 | Re: bulk load performance question |