How CA PMO Optimizes Directory Searches › Searches Initiated by a Program or Application › How CA PMO Optimizes Program-initiated Searches › Directory Searches of Private and LNKLST Libraries (Optimized by CA PMO)

Directory Searches of Private and LNKLST Libraries (Optimized by CA PMO)

If a program issues a BLDL/FIND request to initiate a directory search, the request could be resolved by an in-storage search, if LLA is managing the libraries in the concatenation. However, at this point CA PMO gains control:

1. CA PMO searches the JOB/STEP/TASK library entries in the hash tables for the member.
   1. If the directory entry for the member is found in one of the hash tables, the search is resolved successfully from the hash table. DASD I/O is avoided because CA PMO located the member using an in-storage search.
   2. If the member does not have a hash table entry, CA PMO searches the LNKLST entries in the managed list for the member.
2. CA PMO searches the managed list.
   1. If CA PMO finds an entry for the member in the managed list, and the entry shows that the member was found during a previous LNKLST search, the search ends successfully. DASD I/O is avoided because CA PMO located the member using an in-storage search.
   2. If CA PMO finds an entry for the member in the managed list, and the member was not found during a previous LNKLST search, the search ends unsuccessfully. DASD I/O is avoided because CA PMO can determine using an in-storage search that the member cannot be found.
   3. If the member does not have an entry in the managed list, CA PMO returns control to the system directory search function.
3. The z/OS search function looks for the member in the LLA or the LNKLST libraries. This search may require DASD I/O.
   1. If z/OS finds the directory entry for the member, the search ends successfully. CA PMO adds the directory entry and owning LNKLST library's index to the managed list, marking the managed list entry member found. This allows CA PMO to resolve future directory searches for this member.
   2. If z/OS does not find the directory entry for the member, the search ends unsuccessfully. CA PMO adds the member to the managed list, marking the entry member not found. This allows CA PMO to resolve future directory searches for this member.

The following illustration shows this second type of CA PMO optimized directory search. The in-storage directory searches in steps 1 and 2 of this sequence replace the DASD I/O in the non-optimized directory search against private and LNKLST libraries (see the illustration titled Private and LNKLST Library Search.