以下是关于Priv Mode的一些解释，对于分析和解决Priv Mode有帮助，关于SAP系统性能优化可以做的一些动作可参考 SAP系统慢的一些举措。
PRIV Mode: 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).
Why Work Process goes in Priv Mode
A work process goes into PRIV mode, if the particular open transaction process has taken up all the memory in the extended memory
(upto its quota- define by parameter ZTTZ/roll_extension), roll area memory in work process (defined by parameter ZTTA/roll_area) and then finally it starts taking up memory from Heap memory. When a work process starts using Heap memory, it goes into PRIV mode.
No work process multiplexing
Once a work process enters PRIV mode, work process multiplexing is no more possible for that open transaction.
This is because once the WP goes into PRIV mode, it is not available to any other transactions and we only have a limited number of work processes.
How to prevent dialog work process to enter in Priv Mode
Please make sure the parameters below are defined in RZ10 instance profile:
rdisp/max_priv_time – Used to define the maximum time that a work process can remain in PRIV mode. (After this the work processes is terminated and restarted). This is reasonable because beyond the time limit set, it is imperative to assume that the program using the work process is in efficient. (in case a program really needs that much time, it needs to be scheduled as a background job).
rdisp/wppriv_max_no– This parameter defines the maximum number of work processes that can be in PRIV mode. Very useful.
ABAP/heaplimit – Make sure that a parameter is defined. This ensures that if a program eats up a certain amount of heap memory, the work process being used can be terminated.
And finally please do check if your extended memory allocation is not big enough. the parameter em/initial_size_mb defines the fixed size of extended memory. Increasing this size only if you find that a lot of processes are frequently going into PRIV mode.