Parameter
ztta/roll_extension
Short text
Quota for Extended Memory
Parameter Description
This values specifies the amount of memory in bytes that a user context can allocate to extended memory. The value refers to the amount of memory that an external session (=SAP window) allocates.
If the entered value is exceeded, memory is first allocated from the roll area again, until this is full, and then heap memory is allocated (see ztta/roll_area ).
(Data in the roll area is copied at context change. When heap memory is allocated, the assignment of this work process to this user context is fixed, and it is no longer available for other user contexts (PRIV mode).) )
If you set the value too high, an individual user could cause a bottleneck in the extended memory by increasing the size of his or her user context. Other smaller user contexts would therefore take work processes into PRIV mode, before their permitted quota was exhausted.
Aim
– Minimize number of work processes in PRIV mode.
– Distribute extended memory fairly.
Parameter Unit
Bytes
Default Value
250000000 (250 MB) (Others)
2000000000 (2GB) (Microsoft Windows NT)
Remove the quota, because dynamic extension means that there is always sufficient extended memory.
Default Value
250000000 (250MB) Lower if extended memory is scarce and must be distributed more fairly.
Microsoft Windows NT
2000000000 (2GB) = Remove the quota. The quota for a user context in the extended memory is em/address_space_MB (reserved memory area for extended memory in the work process)
Who is permitted to make changes?
The customer. No manual maintenance is necessary for Microsoft Windows NT.
Are other parameters affected or dependent?
ztta/roll_extension only takes effect if its value is lower than em/initial_size_MB. Increasing the size of ztta/roll_first saves extended memory, but leads to an increased load during the context switch.
Operating System Restrictions
See above
Database System Restrictions
None
