Re: Re: Paginating searchs = performance problem

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. Ivo