Play 2.3 JPA Hibernate MySQL Pooling/Connection Error - mysql

Question

I'm developing a Play 2.3 Application with JPA/Hibernate and use a Heroku/ClearDB.com MySQL Database for this but after the application connects successfully to the DB I get following error:
[error] c.j.b.h.AbstractConnectionHook - Failed to acquire connection to jdbc:mysql://eu-cdbr-west-01.cleardb.com:3306/heroku_b7ea7b2d2972532 Sleeping for 1000ms and trying again. Attempts left: 10. Exception: null.Message:User 'badd25925bdd5f' has exceeded the 'max_user_connections' resource (current value: 10)
com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: User 'badd25925bdd5f' has exceeded the 'max_user_connections' resource (current value: 10)
I tried almost everything I saw on other posts but nothing helped... I think it has to do with pooling...?
persistence.xml
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" 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_2_0.xsd">
<persistence-unit name="defaultPersistenceUnit" transaction-type="RESOURCE_LOCAL">
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<properties>
<property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect"/>
<property name="hibernate.hbm2ddl.auto" value="update"/>
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://eu-cdbr-west-01.cleardb.com:3306/heroku_b7ea7b2d2972532?reconnect=true"/>
<property name="javax.persistence.jdbc.user" value="badd25925bdd5f"/>
<property name="javax.persistence.jdbc.password" value="XXX"/>
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/>
<property name="hibernate.show_sql" value="false"/>
<property name="hibernate.c3p0.min_size" value="2"/>
<property name="hibernate.c3p0.max_size" value="9"/>
<property name="hibernate.c3p0.timeout" value="300"/>
<property name="hibernate.c3p0.max_statements" value="50"/>
<property name="hibernate.c3p0.idle_test_period" value="3000"/>
</properties>
</persistence-unit>
</persistence>
application.conf (relevant part)
db.default.driver=com.mysql.jdbc.Driver
db.default.url="jdbc:mysql://eu-cdbr-west-01.cleardb.com:3306/heroku_b7ea7b2d2972532"
db.default.user="badd25925bdd5f"
db.default.password="XXX"
jpa.default=defaultPersistenceUnit
Thanks a lot for your help!

Answer 1

I don't know about using Hibernate, but with Ebean the connection pool by default is managed by BoneCP. Try to configure it in your application.conf:
# Max connections = partitionCount * maxConnPerPartition
db.default.partitionCount=2
db.default.maxConnectionsPerPartition=5
or in your persistence.xml:
<property name="bonecp.partitionCount" value="2" />
<property name="bonecp.maxConnectionsPerPartition" value="5" />

Answer 2

The error says that you are using more connections then your plan .So you can
Either upgrade you db plans see https://addons.heroku.com/cleardb#ignite
or
You can try scaling down your aplication see https://devcenter.heroku.com/articles/scaling

Answer 3

Solution to this problem (for Play 2.3) was to add the play-hikaricp library to the application.