Loading Members to Cache

%%GLOBAL or %%LIBSYM/%%MEMSYM members can be placed in cache memory, from where they can be accessed as needed. If the members are placed in cache, the JCL accesses the contents from the cache, instead of accessing the members themselves.

This can be very advantageous if many jobs access %%GLOBAL or %%LIBSYM/%%MEMSYM members, because each access of the member increases I/O and processing overhead.

Only those %%GLOBAL or %%LIBSYM/%%MEMSYM members that are specifically requested are loaded to cache. Requests are generally made by listing the desired %%GLOBAL or %%LIBSYM/%%MEMSYM members in a special cache list member in the DAGLOBAL library. This cache list member (default name: CACHLST) is pointed to by the AECACHL parameter in the CTMPARM member in the IOA PARM library.

Members are listed in the cache list member in the following format:

%%GLOBAL memname

where memname is the name of the %%GLOBAL member in the Global library.

The cache list member can optionally contain the following control statement as its first non-comment statement:

%%RESOLVE ALLCACHE

This control statement affects AutoEdit processing only if an AutoEdit variable has not been resolved by searching the %%GLOBAL or %%LIBSYM/%%MEMSYM members identified in the job. The statement instructs Control-M to continue the variable resolution process by checking all members loaded into cache. Members in cache are searched in the same sequence they are listed in the cache list member.

%%GLOBAL or %%LIBSYM/%%MEMSYM members are loaded to cache at time of Control-M startup.

To reload %%GLOBAL or %%LIBSYM/%%MEMSYM members to cache between Control-M startups or to stop using AutoEdit cache, see the corresponding topic in the INCONTROL for z/OS Administrator Guide.