Re: How to get the total number of rows with a query - Mailing list pgsql-general

From Ron Johnson
Subject Re: How to get the total number of rows with a query
Date
Msg-id 1060811635.4577.16.camel@haggis
Whole thread Raw
In response to How to get the total number of rows with a query "limit" ?  (proghome@silesky.com (krystoffff))
Responses Re: How to get the total number of rows with a query  (Franco Bruno Borghesi <franco@akyasociados.com.ar>)
List pgsql-general
On Wed, 2003-08-13 at 08:43, krystoffff wrote:
> Hi
>
> I would like to paginate the results of a query on several pages. So I
> use a query with a limit X offset Y to display X results on a page,
> ok.
>
> But for the first page, I need to run the same query with a count(*)
> to know how many pages I will get (number total of rows/ X).
>
> The problem is my query is very slow (maybe 5s) because there is much
> worch to do, and on the first page, I need to run this query twice
> (not exactly, but ...) so the page is very very slow to load.
>
> My question is : is there a function to get the total number of rows
> even on a query with "limit" ? Or what could I do else ?

Presuming that this is your own app, and not psql, why not suck the
result set into a doubly linked list (or dynamic list, if you use
Python, Perl, etc)?

There's also the possibility of "chunked buffers", where you malloc,
say, 8KB before the query runs, and when that gets full, realloc
to add more space, and continue until the query completes.

--
+---------------------------------------------------------------+
| Ron Johnson, Jr.        Home: ron.l.johnson@cox.net           |
| Jefferson, LA  USA                                            |
|                                                               |
| "Man, I'm pretty.  Hoo Hah!"                                  |
|    Johnny Bravo                                               |
+---------------------------------------------------------------+



pgsql-general by date:

Previous
From: Dennis Gearon
Date:
Subject: Re: Sorting Problem
Next
From: "Gregory S. Williamson"
Date:
Subject: Re: importing db as text files