Changes to Existing Features › CA Datacom/DB Changes › CBS Performance

CBS Performance

Compound Boolean Selection (CBS) performance has been enhanced as follows:

• The Compound Boolean Selection buffer has been changed from a structure needing a lock when adding or deleting entries, to a structure that can use comparing and swapping to get or delete an entry.
• Each set, once it is built, now remains in its expanded form in MUF memory, unless it must be spilled to the CBS index due to the size of the CBS buffer. This eliminates the overhead of reconstituting the set for each SELNR (select-next-record) Compound Boolean Selection Facility command.

The Compound Boolean Selection (CBS) buffer architecture was changed, but most of the changes were internal in nature. From a user perspective, however, the major change of which to be aware is that the CBS buffer is no longer one large, contiguous piece of memory that is acquired at MUF startup. The CBS buffer memory is now acquired and freed as needed for each individual set. This has several ramifications as follows:

• At any given time, the CBS buffer memory is no greater than the amount needed to store open sets.
• CBS buffer architecture can be changed to more efficiently save and restore sets.
• Less memory is therefore used to store any given set, and sets in memory are stored in a simpler, more natural form, so that they do not have to be reconstituted.