Review the symptom table for information to help you troubleshoot performance problems.
Problem | Tuning parameters |
Overall throughput and response time are undesirable. | Refer to Increase processor speed and processor cache in Tuning hardware capacity and settings. |
AIX: Memory allocation error | Refer to AIX file descriptors (ulimit) in the section on "Tuning AIX" in Tuning operating systems. |
ORB: Response time and throughput indicate EJB requests with shorter execution times are being denied adequate access to threads in ORB thread pool. | Set the Logical Pool Distribution (LPD) mechanism using the ORB custom properties as described in Object Request Broker service custom properties. |
Linux: Default maximum web container threads set too high. For Linux distributions that are based on the 2.4 and earlier kernels, setting the web container maximum thread size too high will degrade performance. The maximum web container thread should be set to 25. A higher web container thread size will cause too much contention, therefore degrading performance. | Refer to . |
Solaris operating environment: Too many files open | Refer to Solaris file descriptors (ulimit) in the "Tuning Solaris" section of Tuning operating systems. |
Solaris operating environment: The server stalls during peak periods, responses take minutes, processor utilization remains high with all activity in the system processes, and netstat shows many sockets are open to port 80 in CLOSE_WAIT or FIN_WAIT_2 state. | et the Solaris tcp_time_wait_interval and Solaris tcp_fin_wait_2_flush_interval as described in the "Tuning Solaris" section of Tuning operating systems. |
Windows NT or Windows 2000: Netstat shows too many sockets are in TIME_WAIT. | Set the TcpTimedWaitDelay as described in the "Tuning Windows NT or Windows 2000" section of Tuning operating systems. |
Under load, client requests do not arrive at the Web server because they time out or are rejected. | Set the ListenBackLog as described in the "IBM HTTP Server" section in Web server tuning parameters. |
WebSphere Application Server performance decreased after an application server from another vendor was installed. | Set the IIS Permission properties as described in the "Microsoft Internet Information Server (IIS) - Windows NT and Windows 2000" section of Web server tuning parameters. |
The Percent Maxed metric from the Tivoli Performance Viewer indicates that the Web container thread pool is too large or too small. | Set the Maximum size as described in Thread pool settings. |
Netstat shows too many TIME_WAIT state sockets for port 9080. | Set the MaxKeepAliveConnections and the MaxKeepAliveRequests as described in HTTP transport custom properties. |
Too much disk input and output occurs due to paging. | et the Maximum heap size as described in Java virtual machine settings. |
The Percent Used metric for a data source connection pool from the Tivoli Performance Viewer indicates the pool size is too large. | Set the Maximum connection pool and Minimum connection pool as described in Connection pool settings. |
The Prepared Statement Discards metric from the Tivoli Performance Viewer indicates that the data source statement cache size is too small. | Adjust the Statement cache size as described in Data source settings. |
Too much disk input and output occurs due to DB2 writing log records. | Adjust the DB2 MinCommit parameter as described in DB2 tuning parameters. |
The Percent Maxed metric from the Tivoli Performance Viewer indicates that the Object Request Broker thread pool is too small. | Refer to EJB method Invocation Queuing. |
The Java Virtual Machine Profiler Interface (JVMPI) from the Tivoli Performance Viewer indicates over-utilization of objects when too much time is spent in garbage collection. | Refer to the section on "Detecting over-utilization of objects" in Java memory tuning tips. |
The Used Memory metric from the Tivoli Performance Viewer shows memory leaks and the Java code displays an Out of Memory exception. | Refer to the section on "Detecting memory leaks" in Java memory tuning tips. |
Throughput, response time and scalability are undesirable. | If the application permits, exploit the dynamic cache service as described in Configuring the dynamic cache service to improve performance. |
Startup performance is poor. | Set an initial heap size of at least 50MB (-Xms50m) as described in Java virtual machine settings. |
For current information available from IBM Support on known problems and their resolution, see the following topics on the IBM support page.
IBM Support has documents that can save you time gathering information needed to resolve this problem. Before opening a PMR, see the IBM Support page.