Tuning Database Connectivity

Use

Access to the persistence layer typically slows down client request processing, since it involves the establishment of a database connection, and database operations are time-consuming. With J2EE Engine, you can configure database connection pools.

Activities

JDBC Connector Service enables you to configure a database connection pool for each DataSource you use. You can set the initial and the maximum number of connections in the pool, as well as their lifetime. For more information about these settings, see Managing Connection Pooling.

Guidelines

·        Since each client request on the J2EE Engine server processes runs in a separate application thread, you should configure the number of database connections in the pool considering the maximum number of application threads set on the server processes. The application thread number is also the maximum number of client requests that are processed concurrently on the server. A single client may use several database connections, and you can define the application thread number and the number of pooled database connections considering the average connections-per-user number. The application thread number is configured in the properties of Application Thread Manager. For more information, see Configuring the Thread Pool.

However, when you define the maximum number of pooled connections, you should also take into account the number of server processes  that you have in your cluster. If the overall number of connections is too big, this may deteriorate the database performance.

·        To limit the time during which an application thread remains locked while waiting for a database connection, you can decrease the value of the Maximum Time to Wait for Connection property for the DataSource. For more information, see Managing Connection Pooling.

Note that the good performance of the application also depends on its implementation. With regard to database connectivity, for example, it is very important that you close your connections after using them. For more information, see Accessing DataSource.