You can set any c3p0 properties in your hibernate config using the prefix hibernate. Whether and how much statement pooling will help depends on how much parsing, planning, and optimizing of queries your databases does when the statements are prepared. Note that pool configuration parmeters such as maxPoolSize are enforced on a per-authentification basis! System properties override settings in c3p0. However, if you wish to place configuration information elsewhere, you may place c3p0 configuration information in the XML file format only! Definite gap in the market there.
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You can ensure the reliability of your Connections by testing them, rather than by tossing them.
C3P0 Connection Pooling Example
Applications that use ComboPooledDataSourceor that wrap any c3p0-implemented unpooled DataSource can use the simple user property. Users must take care to clean up any non-standard resources returned by a vendor-specific method.
Each PooledDataSource within your application may have the following attributes embedded within its ObjectName: But this is also the most costly choice from a client-performance perspective. ConnectionCustomizers can be configured via user-defined configuration extensions. The default is AUTO. Given an identityTokenyou can use the method C3P0Registry.
Method object for the non-standard method you wish to call as an argument. The JDBC spec is unforgivably silent on what should happen to unresolved, pending transactions on Connection close. Now, for enhanced performance, it uses code-generated, nonrefective implementations.
Under other circumstances, the overhead of statement pooling can slightly harm performance. The linked cleanup method is for closing the datasource, what isn’t needed in most projects because the DS lives as long as your app is running.
java – JDBC Connection pooling using C3P0 – Stack Overflow
You can also use this property to specify an alternative location in the ClassLoader resource path, e. Begin by setting testConnectionOnCheckout to true and get your application to run correctly and stably. Obviously, if a non-zero value is set, it should be to a value longer than any Connection should reasonably be checked-out. You will find that c3p0 registers MBeans under the domain com. If you use the DataSources factory class, and you want to programmatically override default configuration parameters, make use of the PoolConfig class:.
However, there is special support for defining keys and values for the extensions Map in configuration files. Enhanced performance c3pl the purpose of Connection and Statement pooling, and a major goal of the c3p0 library. DataSource scheme for acquiring database Connections. If you are sure your application only makes one PooledDataSourcesor you can distinguish between the DataSources by their configuration properties inspected via “getters”the first method jdhc be sufficient.
If you want to merge programmatic changes with preconfigured overrides, you’ll have to use getUserOverridesAsString and modify the original settings before replacing.
How to use the C3P0 JDBC connection pool in your Maven Project.
Note that if you use the unwrap methods, c3p0 can not clean up any Statement or ResultSet objects you may generate from raw Connections or Statements. Please provide feedback, bug-fixes, etc!
As this was a major change, and the old codebase had c3ppo extensively used and tested, this parameter was added to allow users to revert of they had problems. User-specific overrides taken from a DataSource’s named configuration specified in c3p0-config. Statement and ResultSets are carefully cleaned up when pooled Connections and Statements are checked in, to prevent resource- exhaustion when clients use the lazy but common resource-management strategy of only cleaning up their Connections.
If, however, some of these tasks “hang”, that is c3o neither succeed nor fail with an Exception for a prolonged period of time, c3p0’s thread pool can become exhausted and administrative tasks backed up. You can affect how c3p0 handles errors in acquiring Connections via the following configurable properties:. Looking for advice in using c3p0 with hibernate?
Ordinarily Connections are checked-in asynchronously so that clients avoid any overhead of testing or custom check-in logic. If you don’t like the long and ugly VMID, you can set your own, or you can turn off this solution to a hypothetical non-problem entirely with the following property:. Databases and JDBC drivers vary widely in this respect. Below is a Tomcat 5. See Appendix A for details.