Other processes cannot use private (heap) memory. After releasing the assigned memory, the operating system still considers the (virtual) memory as being occupied by the allocating process. These characteristics of heap memory require that:
See also:Virtual Address Space of a Work Process
If a dialog work process has used up the roll area assigned to it and the extended memory, private memory is assigned to the work process. The work process goes into PRIV mode (private).
In the parameter settings, ensure that not too many dialog work processes are simultaneously in the PRIV mode, since this lowers system performance.
The otherWork Process types (background, update, enqueue and spool work processes) are assigned heap memory after the roll area is used up. Allocating Extended Memory is not useful since no context change occurs for these processes.
Automatic Termination of PRIV Mode Processes
If too many dialog work processes run in the PRIV mode in an SAP application server, performance problems arise. The normal processing of user inquiries is slowed down by the PRIV mode work processes.
The SAP System offers a mechanism that lets you terminate non-active dialog processes in the PRIV mode. This mechanism helps reduce performance problems.
The mechanism works as follows:
In the PRIV mode, a maximum number (n) of dialog work processes can run without any time restrictions.
To determine this number n, set the value of the profile parameterrdisp/wppriv_max_no. If a value is not entered, the SAP System determines this number using the following formula:
the number (n) is set to the greater of the 2 following values:
If more than (n) dialog work processes are active and the time span set in parameterrdisp/max_priv_time (default 600 seconds) has elapsed, the transaction for that PRIV process, which has spent the longest possible time in PRIV mode, is reset.
You have configured 10 dialog work processes on one SAP instance. The parameters
Then, the SAP System checks periodically if more than 5 dialog work processes are in PRIV mode after 600 seconds (10 minutes). If this is the case, the transaction is reset that has been in PRIV mode for the longest time. A corresponding dialog box appears to the user.
If performance problems arise, you can change these parameters, but do this only after consulting with SAP.
Non-dialog work processes (background, update, etc.) are not contained in this mechanism and are also not considered.