Are prepared statements cached server-side across multiple page loads with PHP?

Question

I learnt about prepared statements when making a JDBC-enabled Java application, and my app uses a connection pooling layer that assures me that prepared statements are cache

Answer 1

The only true answer is it depends.

Prepared statements are finicky beasts when it comes to MySQL. There are a great number of factors that determine whether or not a prepared statement is cached.

The general idea is if your version is < 5.1.17, the prepared statement is never cached in the query cache, and if using >= 5.1.17, it depends.

Please see the following page in the MySQL 5.1 manual:

http://dev.mysql.com/doc/refman/5.1/en/query-cache-operation.html