Note: Although the DFHTST macro is supported by CICS® Transaction Server for z/OS®,
it is recommended that you use resource definition online (RDO) to define
the equivalent TSMODEL definitions. The TSMODEL resource definition supports
attributes that are not supported by the DFHTST macro; for example, the LOCATION(MAIN/AUXILIARY)
attribute.
The temporary storage table (TST) is a list of generic names (or
prefixes) used to identify sets of temporary storage queues. Generic names
are formed from the leading characters of the appropriate queue names, and
can be up to
seven characters long.
- The generic names coded on a DFHTST TYPE=RECOVERY macro identify queues
for which CICS provides
backout of changes in the event of transaction failure or protection against
system failure.
- The generic name coded on a DFHTST TYPE=REMOTE macro identifies queues
for which CICS routes the temporary storage request to a remote CICS region
or TS server, unless the remote system name (SYSIDNT) is the same as that
of the local CICS. If SYSIDNT is the same name as the local CICS, the queues
specified by the DATAID option are treated by CICS as local queues.
- The generic name coded on a DFHTST TYPE=LOCAL macro identifies queues
as local queues that reside in the CICS region in which the TST is installed.
- The generic name coded on a DFHTST TYPE=SECURITY macro identifies queues
for which resource security checking is required.
Note: DATAIDs using all eight characters define unique temporary
storage queue names.
Choose a naming convention for queue names that enables you
to define many queues with only a few generic names. This reduces considerably
the task of TST definition.
Note: CICS searches the TST for the first prefix that satisfies
the particular search criteria. For example, if CICS searches for temporary
storage queue ABCDEFGH, and the TST contains prefix A followed by prefix AB,
A is selected. To avoid this, define the less-generic entries to the TST before
any more-generic entries, so that the first to be found is the least generic
of all possible matches.
Note that when CICS is looking for DATAIDs
to match against a TS queue name, it searches only the types of entry in which
it is interested for that particular search. CICS searches:
- Local and remote entries when determining whether a queue is remote.
Thus, local and remote entries are regarded as one search category when CICS
is matching a queue name against generic names.
- Recovery and remote entries when determining whether a queue is recoverable.
However, if the leading characters of a queue name match both TYPE=RECOVERY
and TYPE=REMOTE generic names, TYPE=REMOTE takes precedence, and the recovery
option must be redefined in the local region in which the queue resides. (Queues
in a shared TS pool cannot be recoverable.)
- Security entries only when determining whether a queue is subject to security.
When a task modifies temporary storage data designated as recoverable,
the data is protected from modification by a concurrent task by enqueuing
on the queue name. The queue name is not dequeued until the task terminates
or issues a task syncpoint request to designate the end of a logical unit
of work. At this time a log record is written to the system log data set to
provide external information sufficient to recover the data if the system
subsequently terminates abnormally.
You can use these macros to define the TST entries:
- Control section—DFHTST TYPE=INITIAL
- Recoverable temporary storage—DFHTST TYPE=RECOVERY
- Local temporary storage—DFHTST TYPE=LOCAL
- Remote temporary storage—DFHTST TYPE=REMOTE
- Temporary storage security checking— DFHTST TYPE=SECURITY
- Temporary storage data sharing—DFHTST TYPE=SHARED
- End of temporary storage table—DFHTST TYPE=FINAL (see TYPE=FINAL (end of table))