Tune the WebLogic Server

Top Performance Areas 2-11

2.6.2 Tuning Redo Logs Location and Sizing

Managing the database IO load balancing is a non-trivial task. However, tuning the redo log options can provide performance improvement for applications running in an Oracle Fusion Middleware environment, and in some cases, you can significantly improve IO throughput by moving the redo logs to a separate disk. The size of the redo log files can also influence performance, because the behavior of the database writer and archiver processes depend on the redo log sizes. Generally, larger redo log files provide better performance by reducing checkpoint activity. It is not possible to provide a specific size recommendation for redo log files, but redo log files in the range of a hundred megabytes to a few gigabytes are considered reasonable. Size your online redo log files according to the amount of redo your system generates. A rough guide is to switch logs at most once every twenty minutes. Set the initialization parameter LOG_CHECKPOINTS_TO_ALERT = TRUE to have checkpoint times written to the alert file. The complete set of required redo log files can be created during database creation. After they are created, the size of a redo log size cannot be changed. New, larger files can be added later, however, and the original smaller ones can be dropped. For more information see the Oracle Database Performance Tuning Guide.

2.6.3 Automatic Segment-Space Management ASSM

For permanent tablespaces, consider using automatic segment-space management. Such tablespaces, often referred to as bitmap tablespaces, are locally managed tablespaces with bitmap segment space management. For backward compatibility, the default local tablespace segment-space management mode is MANUAL. For more information, see Free Space Management in Oracle Database Concepts, and Specifying Segment Space Management in Locally Managed Tablespaces in Oracle Database Administrators Guide.

2.7 Reuse Database Connections

Creating a database connection is a relatively resource intensive process in any environment. Typically, a connection pool starts with a small number of connections. As client demand for more connections grow, there may not be enough in the pool to satisfy the requests. WebLogic Server creates additional connections and adds them to the pool until the maximum pool size is reached. One way to avoid connection creation delays is to initialize all connections at server startup, rather than on-demand as clients need them. This may be appropriate if your load is predictable and even. Set the initial number of connections equal to the maximum number of connections in the Connection Pool tab of your data source configuration. Determine the optimal value for the Maximum Capacity as part of your pre-production performance testing. If your load is uneven, and has a much higher number of connections at peak load than at typical load, consider setting the initial number of connections equal to your typical load. In addition, consider setting the maximum number of connections based on your supported peak load. With these configurations, WebLogic server can free up some connections when they are not used for a period of time. For more information, see Tuning Data Source Connection Pool Options in Oracle Fusion Middleware Configuring and Managing JDBC for Oracle WebLogic Server.