HP Integrity NonStop J-Series - Manual (Page 53)

Configuring Automatic Transaction Processing
HP NonStop AutoTMF Software User’s Guide—429952-017
4-5
Separate Transactions
when a transactional application has some previously unaudited files that are to be
audited using automatic transactions.
You may also use the ALTER GLOBAL ATMFCOMMONTX command to disable
automatic transactions for all files that are not explicitly configured for those
transactions.
Separate Transactions
Separate transactions are used to access a single file open (indicated by a unique file
number) within its own transaction.
Configure separate transactions to:

request automatic transactions for specific files, even if processes have their own
transactions. (Consider configuring common transactions instead.)

avoid long-running transactions in programs that have unusual locking behavior.

force a single-transaction-per-update. Note that you also must specify
MAXUPDATES 1 to force single-transaction-per-update. Each file configured
through SEPARATETX and MAXUPDATES 1 uses its own separate transaction
that is committed immediately after an update.
Other options you can configure for a separate transaction are NOWAIT,
AUTOCOMMIT and MAXTIME.
A process may have both common and separate automatic transactions; all automatic
transactions in a process are managed independently.
Transaction Creation
Automatic transactions are created on demand, whenever a process accesses an
audited file and the process state and the NonStop AutoTMF configuration indicates
that the access requires an automatic transaction.
Typically, an automatic transaction is created if a process accesses an audited file for a
locking operation or an update operation, and that process does not have its own
transaction. You can configure certain files for automatic transactions, either common
or separate, regardless of the process transaction. You can also configure files that
should not be accessed through an automatic transaction.
The first transactional access on a file OPEN determines if operations on that OPEN
should use automatic transactions. Automatic transactions are used consistently, even
if the program handles transactions inconsistently.
Note. Do not configure files that were previously audited as COMMONTX, since configuring
such files can cause locking problems.
Note. Do not configure files that were previously audited (the application programs already
access them under their own transaction) as SEPARATETX. This can lead to locking problems.