C3p0 connection pooling for jpa in persistence.xml not working?
29,779
Solution 1
I found the answer from this blog : http://blog.hpxn.net/2009/02/05/using-c3p0-and-hibernate-3/
Properties in persistence.xml were just wrong, you should spell them beginning by hibernate :
<persistence xmlns="http://java.sun.com/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd"
version="1.0">
<persistence-unit name="mypersistenceunitname">
<properties>
<property name="hibernate.connection.driver_class" value="com.mysql.jdbc.Driver" />
<property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect" />
<property name="hibernate.hbm2ddl.auto" value="create-drop" />
<!-- Important -->
<property name="hibernate.connection.provider_class"
value="org.hibernate.connection.C3P0ConnectionProvider" />
<property name="hibernate.c3p0.max_size" value="100" />
<property name="hibernate.c3p0.min_size" value="0" />
<property name="hibernate.c3p0.acquire_increment" value="1" />
<property name="hibernate.c3p0.idle_test_period" value="300" />
<property name="hibernate.c3p0.max_statements" value="0" />
<property name="hibernate.c3p0.timeout" value="100" />
</properties>
</persistence-unit>
</persistence>
And then, you will see this fabulous log appear :
2011-08-15 08:58:33 com.mchange.v2.c3p0.C3P0Registry banner
INFO: Initializing c3p0-0.9.1 [built 16-January-2007 14:46:42; debug? true; trace: 10]
2011-08-15 08:58:33 com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource getPoolManager
INFO: Initializing c3p0 pool... com.mchange.v2.c3p0.PoolBackedDataSource@f3a94e12 [ connectionPoolDataSource -> com.mchange.v2.c3p0.WrapperConnectionPoolDataSource@6297f706 ....
Regards, Stéphane (sorry for the bounty)
Solution 2
The configuration looks OK. Activate logging and make sure that C3P0 is starting with the appropriate settings.
2010-10-16 11:58:31,271 INFO [main] o.h.c.ConnectionProviderFactory [ConnectionProviderFactory.java:173] Initializing connection provider: org.hibernate.connection.C3P0ConnectionProvider ...
Author by
DHM
PhD Cognitive Science from ages ago. 30 years of programming and product leadership. Currently using java, gwt, flex.
Updated on August 02, 2020Comments
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DHM almost 4 years
I'm still getting JDBC timeouts after trying to configure c3p0 following all of the examples I could find. I'm using JPA, Hibernate, Tomcat, MySQL [AWS RDS]. Here's the snippet from persistence.xml:
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://url..." /> <property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver" /> <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect" /> <property name="connection.provider_class" value="org.hibernate.connection.C3P0ConnectionProvider"/> <property name="hibernate.c3p0.acquire_increment" value="4" /> <property name="hibernate.c3p0.idle_test_period" value="3000" /> <property name="hibernate.c3p0.max_size" value="100" /> <property name="hibernate.c3p0.max_statements" value="15" /> <property name="hibernate.c3p0.min_size" value="5" /> <property name="hibernate.c3p0.timeout" value="100" />
And the error log:
09:18:51.776 WARN org.hibernate.util.JDBCExceptionReporter - SQL Error: 0, SQLState: 08S01 09:18:51.777 ERROR org.hibernate.util.JDBCExceptionReporter - The last packet successfully received from the server was 38,491,585 milliseconds ago. ...
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Snicolas almost 13 yearsLogging is activated (Indeed I use jetty, a webserver and it logs everyting). I got the very same persistence file, c3po and c3po for hibernate both are my classpath (web-inf/classes, and everything is deployed through maven). But I got no logging information about c3po.Help please
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Tony over 6 yearscan you help stackoverflow.com/questions/47011116/…