Version 14.0 › CA Datacom Tools Products › New Features and Enhancements › MUF Additional Buffer Pools

MUF Additional Buffer Pools

Support has been added for additional buffer pools as alternatives to the DATAPOOL and SYSPOOL Multi-User Facility (MUF) startup options. This enhancement provides a process by which databases and data areas can be assigned to the alternate buffer pools.

In Version 12.0, the CA Datacom/DB MUF supported one common high level index (IXX) buffer pool, one common low level index (DXX) buffer pool, and two data area buffer pools (normal and large). This enhancement allows more pools of each type, that is, alternate IXX buffer pools, alternate DXX buffer pools, and alternate data buffer pools. These pools are completely optional. Each of these three types of buffers can have up to 99 alternate buffer pools.

If you want to use these alternate buffer pools, define the pools and specify which areas and database IDs (DBIDs) use these alternate pools.

This facility can be used to increase memory resources for selected areas and to restrict memory for other selected areas. The reason it would be used is to improve performance with regard to accessing selected databases.

Important:

• Take into consideration that using additional buffer pools makes tuning the MUF more complex. For example, if an area is restricted to a small number of buffers, I/O for the area can be exponentially increased by additions to the MUF I/O counts and CPU time, as well as increasing the user program elapsed times significantly.
• The MUF startup option ACCESS is required to be set to OPTIMIZE for every DBID with an area in an alternate buffer pool.
• Areas (and all data areas) that use alternative buffer pools are required to be loaded with URI.
• Moving an open area to a different pool requires that the DBID be fully closed.
• Index buffers (IXX/DXX) default to (and should be) 64-bit memory in z/OS. Data buffers, however, are in 31-bit memory and are constrained by the region size which has many requirements placed upon it that limit it to much less that 2g. Also take into consideration that virtual memory is, at some point, backed by real memory.