The persistence mechanism usually involves the JDBC API. Because JDBC requires manaul coding, the SQL that runs against a database instance, it is critical to optimize the SQL statement that are used within the application. Also, conifgure the database server to support the optimal performance of these SQL statements.
If your using JDBC API, you must consider including prepared statements and batching. Also always use the container managed transactions.
You should tune data source for optimial performance.
Important Note: In general, the type 2 JDBC driver is recommended. However, the type 4 JDBC drivers perform faster in the area of multi-row fetch.
Some applications generate a high rate of writes to the WebSphere Application Server transaction log. Locating the transaction log on a fast disk or disk array can improve response time