Performance Monitoring Infrastructure (PMI)
Performance Monitoring Infrastructure (PMI) is the core monitoring infrastructure for WebSphere Application Server and WebSphere family products like Portal, Commerce, and so on. The performance data provided by WebSphere PMI helps to monitor and tune the application server performance. PMI provides database connection pool size, servlet response time, EJB method response time, JVM garbage collection time, CPU usage, and so on.
Performance bottlenecks in the application server can be identified and fixed. For instance, one of the PMI statistics in the Java DataBase Connectivity (JDBC) connection pool is the number of statements discarded from prepared statement cache. This statistic can be used to adjust the prepared statement cache size in order to minimize the discards and to improve the database query performance.
PMI data can be monitored and analyzed using Tivoli Performance Viewer (TPV), other Tivoli tools, our own applications, or third party tools. TPV is graphical viewer for PMI data that ships with WebSphere Application Server. Performance advisors use PMI data to analyze the run-time state of the application server, and provide tuning advice to optimize the application server resource utilization.
PMI data can also be used to monitor the health of the application server. Some of the health indicators are CPU usage, Servlet response time, and JDBC query time. Performance management tools like Tivoli Monitoring for Web Infrastructure and other third party tools can monitor the PMI data and generate alerts based on some predefined thresholds.
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