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.