如果使用数据源，请休眠“ connection.pool_size”属性

Question

I am using hibernate 4.0.1 in my Portlet application which deployed on Websphere application server, I am referring to datasource configured on the application server from the hibernate configuration, my question is should I use "connection.pool_size" property OR "c3p0" to set the connection pool size or no ? , As the data source on server already have connection pool size with 10.

In other words, Which take the priority, the Hibernate configuration or the datasource configuration for connection pooling and which is better ?

Thanks in advance.

Answer 1

Datasource makes limitation for incoming connections. If you use CP with for example 20 connections - maximum it will get 10 connections from 20. So your dsource pool size should be 20 or more.

Answer 2

When using a data source configured in WebSphere Application Server, which you access by JNDI name, either directly or by providing the JNDI name to your Hibernate config, you end up with connections being pooled by the application server by default. In additional to connection pooling, you also gain transaction enlistment, connection sharing, statement caching and other value adds. The application server does not detect the presence of alternate connection pooling and disable its own. Regarding your question about priority, neither takes priority. If a data source or other implementation provides its own connection pooling, you would end up with pooling being done at both layers, which is likely undesirable. If you need to or prefer to, it is possible to manually disable the application server's connection pooling and statement caching while preserving the other capabilities that the application server provides (transaction enlistment and so forth) by setting the connection pool's aged timeout to immediate and the data source's statementCacheSize to 0. This would allow you to try with either implementation and judge for yourself which performs better in your particular scenario.