HP Integrity NonStop H-Series - Manual (Page 63)

Configuring Automatic Transaction Processing
HP NonStop AutoTMF Software User’s Guide—429952-013
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Setting Transaction Time Out
If there are outstanding automatic transactions when the AUTOCOMMIT time limit is
reached, the NonStop AutoTMF runtime takes the following actions:
1. Forces the commit of all automatic transactions,
2. Issues an EMS message,
3. Terminates the process with an abend.
The program has to be restarted but no data is lost.
To use the AUTOCOMMIT feature effectively, the time limit should be set to be lower
than the TMF AutoAbort time limit by at least 5 minutes. The default value for
AUTOCOMMIT is 115 minutes, based on the default TMF AUTOABORT time limit of
120 minutes. If you set the TMF AUTOABORT limit to a different value, you must set
the AutoTMF AUTOCOMMIT accordingly (AUTOABORT - 5 minutes).
Setting Transaction Time Out
As mentioned in Reducing causes of unilateral aborts above, some programs might
need to hold locks for a longer period than is permitted by the TMF AutoAbort setting.
An alternative to increasing the AutoAbort time limit for all transactions is configuring a
time out value for automatic transaction, provided your system is running TMF version
3.6 or later.
To specify how long an automatic transaction can live, set the TXTIMEOUT file or
program attribute or the ATMFTXTIMEOUT global parameter. Defining a TXTIMEOUT
value effectively sets the TMF AutoAbort time limit, but only for a specific program, a
specific file or for all automatic transactions.
TXTIMEOUT value can be set as follows:
•
to a value between 5 and 515 minutes
•
to NEVER, to ignore the TMF AutoAbort setting
Note that the AutoTMF AutoCommit time limit always applies. If you configure a
TXTIMEOUT value that exceeds the AutoCommit time limit, adjust the AutoCommit
accordingly.
Limitations
Program Logic
•
A program must make one call to OPEN or to FILE_OPEN_ before the first call to
any procedure that requires an open file number. Such procedures include READ,
WRITE, KEYPOSITION, CONTROL, SETMODE, and so on. These calls to OPEN
or FILE_OPEN_ allow the NonStop AutoTMF runtime to allocate and initialize its
data structures.
This requirement applies only to the first file-system procedure call made by the