How CA PMO Works › How the Software Cache Works

How the Software Cache Works

There are two main components of CA PMO-optimized directory searches: a managed list and a set of hash tables. These components form an in-storage software cache. CA PMO uses its in-storage software cache to resolve directory searches. This reduces the DASD I/O typically associated with library directory searches. When a BLDL/FIND request is issued, CA PMO intercepts it and attempts to locate the specified member in the software cache:

• For BLDL/FIND requests that are issued for members of LNKLST libraries, CA PMO first looks in the managed list. If it finds the requested member there, the request is satisfied; otherwise, CA PMO passes the request to z/OS. The directory search routine searches LLA if it is active. (Note that when you use CA PMO you may want to turn off LLA.) If LLA is inactive, a DASD I/O search takes place against the LNKLST library concatenation.
• For BLDL/FIND requests for members of private libraries, CA PMO starts its search in the hash tables. A search for a private library can be resolved from a hash table, eliminating DASD I/O, as long as CA PMO has a hash table for each private library in the concatenation. DASD searches take place for private libraries without hash tables.

  If you use both LLA and CA PMO, you should not allow LLA to manage any private libraries. LLA does not detect updates and it does not automatically refresh its storage areas, whereas CA PMO does both of these activities. Additionally, CA PMO resolves cross-system updates for private library members by finding the updated versions on DASD. If LLA manages any private libraries, CA PMO may receive update information from LLA instead of DASD, and this may not provide the most current information available.