Re: multiple databases

From: "Michael Hall" <lists@mulga.com.au> > I'd like to run this past anyone who'd care to comment before I get too > far down the track I'm considering taking with a PHP web portal site. > > Is it a wise idea to have a PHP web application running on multiple > databases? Everything I've done to date has run off one database, no > matter how large it got. With the current small portal site, the idea is > to break a monolithic database up into around 10 smaller databases, each > of which should be able to be backed up to a floppy. Not all databases are > called on each page, but up to 6 or so could be. > > What are the performance implications (slower, obviously, but 10 times > slower?). Performance beyond what the human mind can perceive is not > relevant to me. > > Should I use mysql_connect or mysql_pconnect for each db connection ? > > Should I be careful to use mysql_close with each connection? > > Any advice appreciated. > > Mick > Do you mean 10 different database servers, or 10 databases on the one server? As far as I know, separate databases on the one server give the same performance as separate tables in one database. With separate database servers you will run into new problems such as: -) additional connection overhead for each server, if you need to access more than one server in a page -) can't combine data from servers, e.g. can't JOIN tables Persistent connections may or may not help. Using persistent connections could negate the connection time overhead, but you get a memory overhead instead - if you have 40 connections open, there's got to be 40 mysqld processes (threads?) running too. Cheers Simon Garner