TRANSFER Reference Manual

Commonly Used Fields
TISERV UOW Descriptions
069139, Update 1 to 40969 Tandem Computers Incorporated 2–15
NON-DELIV-NOTIFY
indicates whether the originator requested a non-delivery notification if delivery
fails:
Y The originator requested non-delivery notification if delivery fails.
N The originator did not request non-delivery notification if delivery fails.
STORAGE-STAT Field Several UOWs related to the depot storage statistics facility have fields that include the
STORAGE-STAT DDL definition. This definition is specified as:
DEF storage-stat TYPE BINARY 64.
UPDATE-CONTROL Field The UPDATE-CONTROL field is used in UOWs that update records maintained
under the TRANSFER delivery system, such as those records comprising item
descriptions. You use this field to ensure that updates are accomplished in an orderly
way. The DDL definition for UPDATE-CONTROL is:
DEF update-control PIC S9(4) COMP.
When your process gains access to a record prior to updating it, you need some
guarantee that another process will not modify that record before your process
completes its own update operations. If another process updates the record that your
process is accessing, the copy of that record is invalid. The TRANSFER delivery
system cannot keep a record locked to prevent a multiple update; instead, the
TRANSFER delivery system must release the record locks when TMF transactions are
committed or aborted. To resolve this conflict between its own needs and those of
your process, the TRANSFER delivery system uses the UPDATE-CONTROL field as
follows:
1. Each time TISERV completes a record update, it increments the value of an update
control count in that record.
2. When your process requests access to a record, TISERV returns the current update
control count in the response UOW.
3. When your process modifies a record and subsequently requests an update to that
record, TISERV checks the value in the UPDATE-CONTROL field against the
current update control count of the record. If these two values match, the update
is allowed to proceed. If the values do not match, this indicates that another
update took place while your process was accessing the record. TISERV returns
an error indication to your process; your process should retry the access and
update operations in this case.