On Wed, June 13, 2007 10:17 am, Robert Cummings wrote: > On Wed, 2007-06-13 at 10:36 -0400, Guillaume Theoret wrote: >> Hi everyone, >> >> Can anyone recommend any good books/resources for php and mysql >> performance management? I'm more interested in the software >> development side (as opposed to server configuration) of things. I'm >> looking for anything that would be good to know when working on >> websites that get millions of hits a day. >> >> Also, if anyone knows of any resources/discussions that illustrate >> the >> relative performance of joins vs multiple selects I'd love to check >> it >> out. > > JOIN will almost always be faster by virtue of the query being > optimized > and doing the work within a single request. In my limited experience, under shared server with seriously constrained resources, the exact opposite is true... Oh, sure, for a SMALL table and an easy JOIN on straight-forward indexed fields, the JOIN is faster. But every time I've ended up with a large table and a JOIN that was anything remotely interesting (read: complex and un-indexable) the server just gets swamped. And often, a simple straight-forward select to get a handful of rows followed by another query, or even one query per result row, was MUCH faster. It's entirely possible that I just don't know SQL well enough to get the schema and indexing right, but I try to index the "obvious" fields that will be used in the join. This also may not even be applicable to a site that scales up with the kinds of resources you'd throw at that. But I'd certainly recommend writing small simple crude test code with a dedicated testing server and simulated real life load conditions rather than just "guessing" at what might be fastest. An hour's testing could save you weeks/months of development in this case. -- Some people have a "gift" link here. Know what I want? I want you to buy a CD from some indie artist. http://cdbaby.com/browse/from/lynch Yeah, I get a buck. So? -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
