tomcat7 - jdbc datasource - This is very likely to create a memory leak

mysql spring memory-leaks tomcat7 datasource
arahant picture arahant · Mar 26, 2013 · Viewed 48.5k times · Source

I get the following messages in catalina.out log file when tomcat is shutdown. I am using Tomcat 7.x and the Tomcat JDBC data source.

Mar 26, 2013 1:17:52 PM org.apache.catalina.loader.WebappClassLoader clearReferencesJdbc 
SEVERE: The web application [/my_webapp] registered the JDBC driver [com.mysql.jdbc.Driver] but failed to unregister it when the web application was stopped. To prevent a memory leak, the JDBC Driver has been forcibly unregistered. 
Mar 26, 2013 1:17:52 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads 
SEVERE: The web application [/my_webapp] appears to have started a thread named [MySQL Statement Cancellation Timer] but has failed to stop it. This is very likely to create a memory leak.

The first one claims that the DataSource has been forcibly unregistered so that is fine. However it is strange Because I have configured the destroy-method like so:

<bean name="dataSource" class="org.apache.tomcat.jdbc.pool.DataSource" destroy-method="close">
    <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
    <property name="url" value="jdbc:mysql://localhost:3306/mydb"/>
    <property name="username" value="root"/>
    <property name="password" value="password"/>
</bean>

Not sure why I get the second one. The one about the "MySQL Statement Cancellation Timer".

Any help is appreciated

EDIT 1: I tried the fix suggested by @Zelldon and it gets rid of the first error. However the MySQL Statement Cancellation Timer related issue still persists

Answer

Zelldon picture Zelldon · Mar 26, 2013

Try to put the sql Connector/Driver in the tomcat/lib and not in the war. Because every time you deploy the war the connector/driver will be created sometimes the garbage collector cant remove them which will ends in a memory leak. So try to move the connector on the tomcat/lib folder.

Please read the following answers:

Why must the JDBC driver be put in TOMCAT_HOME/lib folder?

How to configure Tomcat to connect with MySQL

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