Overview of WAS data extractor

To use the WebSphere® Performance Analysis Reports, WAS must be enabled in Application Performance Analyzer by your installation, and the WAS data extractor must be turned on when the Observation Request is entered. You select the WAS data extractor in the Options panel when creating a new measurement. The WAS data extractor is valid only if the target job is an active WAS controller address space. The WAS controller is not actually sampled, since no application code runs in a WAS controller. Instead, all WAS requests processed by the target WAS controller are recorded in the sample file. The sampling frequency will be changed to 1 per second and the number of samples will be changed to the sampling duration in seconds when the WAS measurement request begins.

When the WAS data extractor is selected, SMF records are activated for the target WAS controller address space. The SMF records contain information about each WAS request processed by the server. This SMF data is extracted and written to the sample file.

Sequence Numbers

The sequence numbers assigned to unique occurrences of object names (EJBs, servlets, and so on) do not necessarily indicate the order in which the objects were invoked.

CPU and Service Times

CPU time (including zIIP and zAAP time) is measured in microseconds. zIIP and zAAP CPU times are normalized to CP time. Service time (elapsed time) is measured in milliseconds. Total service time can exceed the sampling duration, because WAS processes multiple requests in parallel.

CPU Usage Breakdown

The SMF records contain information at the request level, giving total CPU and service times for each request. If the request invokes the Web container or EJB container, the SMF records contain information for each servlet/JSP or method invoked, to a maximum of 30 unique occurrences. Included in this information is CPU time, service time, and the number of times the object was invoked.

The sum of CPU times and service times for the breakdown will not add up to the CPU time and service time for the request, since not all activity is recorded in the breakdown when processing a request.

Similarly, the invocation count for a servlet/JSP or method will not add up to the request count at the request level.

Request Types

The type of a request is determined by its SMF record. Only a single type is recorded for each request. For example, if a request arrives via HTTP for a managed bean, the request type is HTTP. It will be counted once as an HTTP request. It will not be counted as an Mbean request.