Re: Tomcat/MySql DataSource - Connection Pool does not seem to get initialized

[Ken Jenkins]

Tomcat 5.0.24 uses Apache commons-dbcp 1.1 to do its connection pooling. DBCP did not include the property "initialSize" until release 1.2 so that parameter I had in my <ResourceParams> for the JDBC DataSource was getting ignored. So I upgraded my commons-dbcp and its dependencies (commons-pool and commons-collections) and everything worked. DBCP now will create the specified number of initial connections in the pool.

Incidentally, the upgraded commons-dbcp and its dependencies are included with Tomcat starting with 5.0.27.

Also, in a related matter, according to the JDBC 3.0 spec, there is a Driver property named "initialPoolSize", but commons-dbcp does not seem to use the standard property names that are defined by the JDBC 3.0 spec. I guess its because those property names are for JDBC Drivers. DBCP is just a general purpose db connection pooling lib and is not bound by JDBC specs. See section 11.7 for the standard Driver properties defined by JDBC 3.0. I assume those standard property names defined by the JDBC standard are for the case of when a Driver does the connection pooling itself in a two tier environment as opposed to having the application server taking care of the connection pooling in a three tier environment?