11.11.2 Allocating data local buffers

Organization of this subsection
(1) Multiple RDAREAs with different page lengths
(2) Multiple RDAREAs with different UAP access methods

(1) Multiple RDAREAs with different page lengths

If there are multiple RDAREAs with different page lengths, all RDAREAs with the same or almost the same page length should be allocated to a single local buffer, so that memory utilization efficiency can be improved.

If multiple RDAREAs with very different page lengths are assigned to the same local buffer, the local buffer is allocated as appropriate for the RDAREA with the largest page length. When data pages are input/output on an RDAREA with a small page length, some areas in a single local buffer sector will remain unused, thereby adversely affecting the efficiency of memory usage.

(2) Multiple RDAREAs with different UAP access methods

If multiple RDAREAs have the same page length, but their UAP access methods are different, each RDAREA should be allocated to a different local buffer. Examples of such RDAREAs include RDAREAs with different usage, RDAREAs with frequent sequential processing and infrequent update processing, and RDAREAs subject to frequent addition or update processing.