Measures reported by WDispThreadTest

The SAP Web dispatcher performs load balancing, and passes requests to Internet Communication Managers (ICMs) on the connected application servers rather than to work processes. Besides the pool of worker threads, which process incoming requests, the following ICM components are also implemented as threads:

• Thread Control: This thread accepts the incoming TCP/IP requests and creates (or wakes) a worker thread from the thread pool to process the request. From this point on, thread control initializes the connection info data.

• Worker Threads: These threads handle connection requests and responses. A worker thread contains an I/O handler for the network input and output, diverse plug-ins for the various supported protocols (HTTP, SMTP,…), which are required to be able to decide when the sent packet is finished (depends on the protocol).

• Watchdog: Usually, a worker thread waits for the response, regardless of whether the worker thread is a server or a client. If a timeout occurs, the watchdog takes on the task of waiting for the response. This makes the worker thread available for other requests. When the watchdog receives the response, it informs the thread control components, which then call a worker thread.

• Signal Handler: This thread processes signals sent from the operating system or from another process (for example, the dispatcher).

• Connection Info: This table contains information about the state of the connection, the memory pipes, and the plug-in data for every existing network connection.

• Memory Pipes: These memory-based communication objects are used to transfer data between the ICM and work processes (AS ABAP), or between the ICM and Java server processes (AS Java). There are four pipes for every connection: One data pipe per request and response and one out-of-band (OOP) pipe. The OOB pipe is used for control data.

• Internet Server Cache: The ICM contains another cache to enable a quick response to repeated requests. This cache is not shown in the graphic.

For each thread of the target SAP Web Dispatcher, this test reports the current state and the rate at which requests are processed by the threads.

Outputs of the test : One set of results for each thread of the SAP Web Dispatcher being monitored

The measures made by this test are as follows: