rdisp/ROLL_SHM: Roll Buffer Size


This value specifies the size of the roll buffer in 8 KB blocks.

The roll buffer functions as the cache for the roll file. For a fast change of context to occur, the roll areas of all user contexts should find space in the roll buffer (approximately 1 MB for each user). Buffered data is in the shared memory; accessing this data here is much faster than accessing a file.


The default value is platform-specific and is determined dynamically. This is the default value specified in transaction RZ11. This value should not normally be changed.


For technical reasons the roll buffer size must be at least 10% of the roll file size (parameter rdisp/ROLL_MAXFS: Maximum Roll File Size