Working with PHP 4.4.2 and MySQL 4.1.19, I'm suffering some memory problems on my server (memory allocations, slowness), and would like to know if my mySQL queries are well-designed in terms of memory.
My website allow users to register and to share items with several degrees of privacity, so each time someone accesses webpages I must check which items are public or not, by using SQL queries. I've written code by myself so I may've done some mistakes.
Is there any way to check this mySQL performance? Some tips?