Hi, I have this LAMP application with about 900k rows in MySQL and I am having some performance issues.

Background - Apart from the LAMP stack , there's also a Java process (multi-threaded) that runs in its own JVM. So together with LAMP & java, they form the complete solution. The java process is responsible for inserts/updates and few selects as well. These inserts/updates are usually in bulk/batch, anywhere between 5-150 rows. The PHP front-end code only does SELECT's.

Issue - the PHP/SELECT queries become very slow when the java process is running. When the java process is stopped, SELECT's perform alright. I mean the performance difference is huge. When the java process is running, any action performed on the php front-end results in 80% and more CPU usage for mysqld process.

Any help would be appreciated.

MySQL is running with default parameters & settings.

Software stack -

• Apache - 2.2.x
• MySQL -5.1.37-1ubuntu5
• PHP - 5.2.10
• Java - 1.6.0_15
• OS - Ubuntu 9.10 (karmic)