Tomcat Connection Pool configuration: DataSource type and "Too many connection" error

Question

I'm using the tomcat connection pool via JNDI resources.

In the context.xml:

<Resource name="jdbc/mydb" auth="Container" type="javax.sql.DataSource"
          username="root" password="root" driverClassName="com.mysql.jdbc.Driver"
          maxActive="1000" maxIdle="100" maxWait="10000"
          url="jdbc:mysql://localhost:3306/mydatabase" 
          factory="org.apache.tomcat.jdbc.pool.DataSourceFactory" />

In web.xml:

<resource-ref>
<description>DB Connection</description>
<res-ref-name>jdbc/mydb</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>

From the java classes in which I need db connections, I do this lookup:

Context initContext = new InitialContext();
DataSource ds = (DataSource)initContext.lookup("java:/comp/env/jdbc/mydb");

My first doubt is the DataSource type. Is it the same using javax.sql.DataSource or org.apache.tomcat.jdbc.pool.DataSource?

Moreover, sometimes I obtain a "Too many connections" error. I've read many stackoverflow question/answers about this, but I don't succeed in understanding where the problem could be.

I have followed the tomcat docs, and I close properly result sets, statements and connection.

EDIT

My tomcat version is 7.0.26. So there should be a bug (see link suggested by informatik01 user)

Answer 1

If you put the JDBC resource in the $CATALINA_HOME/conf/context.xml it loads the resource for every single webapp you have deployed. (Which can mean a huge number of connections) If you move that resource to META-INF/context.xml of your webapp it will only load when that specific webapp is deployed. http://tomcat.apache.org/tomcat-7.0-doc/jndi-resources-howto.html

It could also be that you have way too many maxActive and maxIdle.