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I'm struggling with a problem facing c3p0 configuration. I posted a question last week
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C3P0 is an open source JDBC connection pool distributed along with Hibernate in the lib directory. Hibernate will use its org. hibernate.
c3p0 is a Java library that provides a convenient way for managing database connections. In short, it achieves this by creating a pool of connections. It also effectively handles the cleanup of Statements and ResultSets after use.
hibernate. c3p0. timeout – When an idle connection is removed from the pool (in second). Hibernate default: 0, never expire.
c3p0. timeout You specify the timeout period (in this case, 300 seconds) after which an idle connection is removed from the pool).
This is a configuration I am using which keeps resources to a minimum. Of course you'll want to tailor your application to use the resources it needs...
Reference: http://www.mchange.com/projects/c3p0/index.html
testConnectionOnCheckin validates the connection when it is returned to the pool. testConnectionOnCheckOut, although would ensure active connections before use, would be too expensive to do.idleConnectionTestPeriod sets a limit to how long a connection will stay idle before testing it. Without preferredTestQuery, the default is DatabaseMetaData.getTables() - which is database agnostic, and although a relatively expensive call, is probably fine for a relatively small database. If you're paranoid about performance use a query specific to your database (i.e. preferredTestQuery="SELECT 1")maxIdleTimeExcessConnections will bring back the connectionCount back down to minPoolSize after a spike in activity.Below configuration sets poolsize between 3-20. Idle connections are retested every 5 minutes to keep them active. Because of idleConnectionTestPeriod, this will only keep the the minumum number of connections alive. If there are more than 3 connections at the 4-minute mark, it kills those connections freeing resources back to the minimum.
Use of maxIdleTimeExcessConnections and idleConnectionTestPeriod negates the need for maxIdleTime
<Context docBase="myapp" path="/myapp" reloadable="true"> <Resource description="My DB Datasource" name="jdbc/mydb" auth="Container" factory="org.apache.naming.factory.BeanFactory" type="com.mchange.v2.c3p0.ComboPooledDataSource" user="myuser" password="******" minPoolSize="3" maxPoolSize="20" acquireIncrement="1" driverClass="com.mysql.jdbc.Driver" jdbcUrl="jdbc:mysql://localhost:3306/mydb" testConnectionOnCheckin="true" idleConnectionTestPeriod="300" maxIdleTimeExcessConnections="240" /> </Context> If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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