18 Tuning Web Applications

The following sections contain Oracle best practices for tuning Web applications and managing sessions:

Best Practices

Disable Page Checks

You can improve performance by disabling servlet and JDP page checks. Set each of the following parameters to -1:

These are default values for production mode.

Use Custom JSP Tags

Oracle provides three specialized JSP tags that you can use in your JSP pages: cache, repeat, and process. These tags are packaged in a tag library jar file called weblogic-tags.jar. This jar file contains classes for the tags and a tag library descriptor (TLD). To use these tags, you copy this jar file to the Web application that contains your JSPs and reference the tag library in your JSP. See "Using Custom WebLogic JSP Tags (cache, process, repeat)" in Developing Web Applications, Servlets, and JSPs for Oracle WebLogic Server.

Precompile JSPs

You can configure WebLogic Server to precompile your JSPs when a Web Application is deployed or re-deployed or when WebLogic Server starts up by setting the precompile parameter to true in the jsp-descriptor element of the weblogic.xml deployment descriptor. To avoid recompiling your JSPs each time the server restarts and when you target additional servers, precompile them using weblogic.jspc and place them in the WEB-INF/classes folder and archive them in a .war file. Keeping your source files in a separate directory from the archived .war file eliminates the possibility of errors caused by a JSP having a dependency on one of the class files. For a complete explanation on how to avoid JSP recompilation, see "Avoiding Unnecessary JSP Compilation" at http://www.oracle.com/technology/pub/articles/dev2arch/2005/01/jsp_reloaded.html.

Disable Access Logging

Setting the access-logging-disabled element can eliminate access logging of the underlying Web application, which can improve server throughput by reducing the logging overhead. See container-descriptor in Developing Web Applications, Servlets, and JSPs for Oracle WebLogic Server.

Use HTML Template Compression

Using the compress-html-template element compresses the HTML in the JSP template blocks which can improve runtime performance. If the JSP's HTML template block contains the <pre> HTML tag, do not enable this feature.

See jsp-descriptor in Developing Web Applications, Servlets, and JSPs for Oracle WebLogic Server.

Use Service Level Agreements

You should assign servlets and JSPs to work managers based on the service level agreements required by your applications. See Thread Management.

Related Reading

Session Management

As a general rule, you should optimize your application so that it does as little work as possible when handling session persistence and sessions. The following sections provide information on how to design a session management strategy that suits your environment and application:

Managing Session Persistence

WebLogic Server offers many session persistence mechanisms that cater to the differing requirements of your application, including Async-replicated and Async-JDBC modes. The session persistence mechanisms are configurable at the Web application layer. Which session management strategy you choose for your application depends on real-world factors like HTTP session size, session life cycle, reliability, and session failover requirements. For example, a Web application with no failover requirements could be maintained as a single memory-based session; whereas, a Web application with session fail-over requirements could be maintained as replicated sessions or JDBC-based sessions, based on their life cycle and object size.

In terms of pure performance, replicated session persistence is a better overall choice when compared to JDBC-based persistence for session state. However, replicated-based session persistence requires the use of WebLogic clustering, so it isn't an option in a single-server environment.

On the other hand, an environment using JDBC-based persistence does not require the use of WebLogic clusters and can maintain the session state for longer periods of time in the database. One way to improve JDBC-based session persistence is to optimize your code so that it has as high a granularity for session state persistence as possible. Other factors that can improve the overall performance of JDBC-based session persistence are: the choice of database, proper database server configuration, JDBC driver, and the JDBC connection pool configuration.

For more information on managing session persistence, see:

Minimizing Sessions

Configuring how WebLogic Server manages sessions is a key part of tuning your application for best performance. Consider the following:

  • Use of sessions involves a scalability trade-off.

  • Use sessions sparingly. In other words, use sessions only for state that cannot realistically be kept on the client or if URL rewriting support is required. For example, keep simple bits of state, such as a user's name, directly in cookies. You can also write a wrapper class to "get" and "set" these cookies, in order to simplify the work of servlet developers working on the same project.

  • Keep frequently used values in local variables.

For more information, see "Setting Up Session Management" in Developing Web Applications, Servlets, and JSPs for Oracle WebLogic Server.

Aggregating Session Data

This section provides best practices on how to aggregate session data. WebLogic Server tracks and replicates changes in the session by attribute so you should:

  • Aggregate session data that changes in tandem into a single session attribute.

  • Aggregate session data that changes frequently and read-only session data into separate session attributes

For example: If you use a a single large attribute that contains all the session data and only 10% of that data changes, the entire attribute has to be replicated. This causes unnecessary serialization/deserialization and network overhead. You should move the 10% of the session data that changes into a separate attribute.

Pub-Sub Tuning Guidelines

The following section provides general tuning guidelines for a pub-sub server:

  • Increase file descriptors to cater for a large number of long-living connections, especially for applications with thousands of clients.

  • Tune logging level for WebLogic Server.

  • Disable Access Logging.

  • Tune JVM options. Suggested options: -Xms1536m -Xmx1536m -Xns512m -XXtlaSize:min=128k,preferred=256k

  • Increase the maximum message. If your application publishes messages under high volumes, consider setting the value to <max-message-size>10000000</max-message-size>.