Re: Where do a novice do to make it run faster?

[PFC <lists(at)peufeu(dot)com>]

	You got the order slightly wrong I guess.

> 1) hardware

	Would only come first if your RAM is really too small, or you use RAID5  
on write-heavy tables, or what limits you is transaction fsync (hint :  
8.3).
	Adding RAM is cheap.

> 2) rewriting my queries and table structures

	This should really come first.
	Log expensive queries. Note that an expensive query can be a slow query,  
or be a rather fast query that you execute lots of times, or a very simple  
and fast query that you execute really really too often.

	Now ask yourself :
* What is this query supposed to do ?

* Do I need this query ?

	Example :
	You put your sessions in a database ?
	=> Perhaps put them in the good old filesystem ?

	Your PHP is loading lots of configuration from the database for every  
page.
	=> Cache it, generate some PHP code once and include it, put it in the  
session if it depends on the user, but don't reload the thing on each page  
!

	This feature is useless
	=> Do you really need to display a birthday cake on your forum for those  
users who have their birthday today ?

	UPDATEs...
	=> Do you really need to update the last time a user was online every  
time ? What about updating it every 5 minutes instead ?

* Is this query inside a loop ?
	=> Use JOIN.

* Do I need all the rows from this query ?

	Example :
You use pagination and perform the same query changing LIMIT/OFFSET ?
=> Perform the query once, retrieve the first N pages of result, cache it  
in the session or in a table.

* You have a website ?
=> Use lighttpd and fastcgi

* Do I need all the columns from this query ?

* Do I suffer from locking ?

	etc.


Now you should see some easy targets.
For the queries that are slow, use EXPLAIN ANALYZE.
Question your schema.
etc.