Measuring data requests (PMI)

 

PMI Request Metrics allows one to track individual transactions, recording the processing time in each of the major WAS components. Information can be saved to log files and sent to ARM Agents.

As a transaction flows through the system, Request Metrics tacks on additional information so that the log records from each component can be correlated, building up a complete picture of that transaction. The result looks similar to the following

HTTP request /trade/scenario             --------------------------------> 172 ms
      Servlet/trade/scenario             --------------------------------> 130 ms
         EJB TradeEJB.getAccountData      ------------------------------->  38 ms
              JDBC select                -------------------------------->   7 ms 

This transaction flow with associated response times can help users target performance problem areas and debug resource constraint problems. For example, the flow can help determine if a transaction is spending most of its time in the Web server plug-in, the Web container, the enterprise bean container or the backend database. The response time collected for each level includes the time spent at that level and the time spent in the lower levels.

Tools can inject synthetic transactions for tracking the response time. The information provided can be used as an alert mechanism to detect when the performance of particular request type goes beyond acceptable thresholds. The filtering mechanism within Request Metrics may be used to focus on the specific synthetic transactions and can help optimize performance in this scenario.

Three types of filters are supported...

• Originator IP filter
• URI filter
• EJB method name filter

When filtering is enabled, only requests matching the filter generate Request Metrics data, create log records, and/or call the ARM interfaces. This allows work to be injected into a running system (specifically to generate trace information) to evaluate the performance of specific types of requests in the context of normal load, ignoring requests from other sources that might be hitting the system.

 

 

 

 

 

 

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