HP NonStop G-Series - Manual (Page 63)

Configuring Automatic Transaction Processing
HP NonStop AutoTMF Software User’s Guide—429952-014
4-17
Forced Transaction Commit
•
Avoiding sending transactional requests to other processes so that those
processes cannot cause unilateral aborts.
•
Detecting unilateral aborts and abending the process. The program will not make
database updates that assume that earlier updates were completed.
•
Providing transaction isolation controls to prevent a unilateral abort from affecting
external users or database consistency; see the preceding subsection
Transaction
Isolation on page 4-7.
•
Providing an AUTOCOMMIT option that allows you to force all outstanding
automatic transactions to be committed before the process abends, to avoid
reaching the TMF AutoAbort time limit. See subsection
Forced Transaction Commit
below for details.
Unilateral aborts caused by hardware or system failures should be rare.
Reducing causes of unilateral aborts
To reduce other causes of unilateral aborts in production processing, perform these
tasks:
•
Configure TMF to handle the projected transaction load.
•
If programs hold record locks and file locks for long periods, alter the TMF
AutoAbort parameter to avoid aborting long-running automatic transactions. If TMF
version 3.6 or later is running in your system, another option is to configure a
timeout for automatic transactions. See
Setting Transaction Time Out below.
•
Avoid using the TACL STOP and the PATHWAY SHUTDOWN2 MODE
IMMEDIATE commands unless you know that the programs being stopped do not
have pending transactions. Use the
STOP PROCESS command to externally stop
server processes that are reading $RECEIVE
Forced Transaction Commit
As mentioned in the paragraph on Transaction Commit , NonStop AutoTMF software
ensures that normal unaudited locking protocols are observed in order to preserve the
integrity of the program logic. NonStop AutoTMF software assumes that programs are
locking and unlocking records as needed to process a business transaction or unit of
work. Automatic transactions are therefore not committed if a program is holding a lock
on a record or a file.
The case where a program does not conform to the unaudited locking protocol
presents a problem. If a program fails to unlock a record or a file, the program prevents
NonStop AutoTMF software from committing automatic transactions. To deal with such
situations, AutoTMF issues a warning in the EMS log to notify the operator of the long
running transaction when a transaction runs longer than 5 minutes. The warning is
repeated every 5 minutes, until the transaction is committed. (You can suppress these
warnings by setting the file or program attributes
NOWARNLONGTX or the global
parameter ATMFNOWARNLONGTX)