Re: Re: Paginating searchs = performance problem

Robert Cummings wrote:

On Mon, 2006-10-23 at 10:13 +0200, Ivo F.A.C. Fokkema wrote:

On Fri, 20 Oct 2006 12:06:26 -0400, Robert Cummings wrote:

On Fri, 2006-10-20 at 17:22 +0200, Ivo F.A.C. Fokkema wrote:

On Fri, 20 Oct 2006 17:04:35 +0200, Fourat Zouari wrote:

I have PHP/PostgreSQL application were i got a search page with some items to search, am building the search query on server side. I need to display a paginated search and for this i need to get the total count of lines matching the search before OFFSET/LIMITing my page, am i obliged to repeat the query twice ??? first to get the total count, second to get my page. it's very heavy Any one's suggesting better doing ?

As far as I know, this is the only way. The first query, you don't need to sort your data though, and you might be able to drop a join, depending on whether or not you use the joined table in your WHERE clause. But I think due to caching the database will not take a long time for the second query, since it just recently had (almost) the same query - YMMV.

Hell no, don't use the same query twice. Use a count in the first query that only returns 1 row... the count. The second query can return the records (which may be less than the count returns since you're paging).

There must have been a reason why I started doing this... I used to use COUNT(*) first too, then run the full query but somehow this must have not worked for me when searching though a complex set of JOIN'ed tables or so... after which I have my query builder run the query first without the order clause. I'm going to look into this, see if I can track that down. But you're right, I should've mentioned that in his case a COUNT(*) could've been possible, since I didn't know his table structure or query.

You can also use this dirty little sucker that's specific to MySQL (AFAIK):

    SQL_CALC_FOUND_ROWS

Yep mysql specific. Postgres you have to do it the old fashioned way: $count_query = "SELECT COUNT(...)"; $fetch_query = "SELECT " ..... -- Postgresql & php tutorials http://www.designmagick.com/