SAP Library - Find your answers

Requirements

Procedure

Possible causes /Corrective action

• No more R/3 Extended Memory is available.

In this example, work processes 5 and 6 cannot allocate any more Extended Memory because the pool is used up, although its limit for ztta/roll_extension would still allow Extended Memory. They switch into PRIV mode prematurely (see Allocating Memory for User Contexts)

Increase the R/3 Extended Memory pool ( em/initial_size_MB: Extended Memory Pool Size) to prevent the work processes from being switched to PRIV mode.

• The limit for the Extended Memory is too low for most user contexts (set with parameter
ztta/roll_extension). Many contexts allocate heap memory and switch to PRIV mode.

Increase the limit for the Extended Memory using ztta/roll_extension.

• The limit for the Extended Memory for one user context (ztta/roll_extension) is too high. A few user contexts can completely fill the entire Extended Memory, whereby other processes are switched into PRIV mode before the limit is reached.

Decrease the limit for the Extended Memory (set with parameter ztta/roll_extension), or increase the Extended Memory (see ztta/roll_extension).

Symptom

Corrective action

SAP Workload Analysis: Average Response Time per Dialog Step (ms)

Response time per dialog step

The response time of a dialog step is the time required for requesting the dialog from the dispatcher work process to the processing of the dialog through the ending of the dialog in the dispatcher and the transfer of the data to the presentation server.

This also includes the time used for "Roundtrips" to transfer data from the SAP R/3 frontend to the application server and back. This time is recorded as roll wait time on the application server, while it is displayed as GUI time on the frontend. For inefficient networks, such as WAN connections, this time can contribute significantly to the response time, although it uses no resources on the application server, as the context is rolled out and the work process is released.

The response time is usually split into wait time and "dispatched" time. The SAP response time is made up of the following components:

Response time = wait time + "dispatched" time

"Dispatched" time

= Generation times during the runtime

+ Load times for programs, screens, and GUI interfaces

+ Roll times for rolling in work data

+ ABAP processing times

+ Database time

+ Enqueue time for logical SAP locks

+ Roll wait time (not including task types RFC/CPIC/ALE).

The CPU time is not an additive component of the response time, but rather the sum of the CPU time used by the individual components. The CPU time is an independent additional piece of response time information.