HP Integrity NonStop H-Series - Manual (Page 49)

Configuring Automatic Transaction Processing
HP NonStop AutoTMF Software User’s Guide—429952-013
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Automatic Transactions
Automatic Transactions
NonStop AutoTMF software provides transactions when a program is not programmed
to provide transactions. As needed, NonStop AutoTMF software starts and commits
automatic transactions. Nontransactional programs are unaware that automatic
transactions are being created and committed.
While automatic transactions are being created and committed, a process may have its
own transactions, through calls to BEGINTRANSACTION or by inheriting transactions
through messages on $RECEIVE. Such transactions are called process transactions.
The process can manage its own transactions, while its automatic transactions are
managed transparently by NonStop AutoTMF software.
Automatic transactions are created on demand, that is, only when the process
accesses an audited file in a way that requires a transaction.
Automatic transactions are used only for database operations within a single process;
automatic transactions are never exported to server processes.
Automatic transactions are always committed; they are never aborted.
Common Transaction
The common transaction is the default type of automatic transaction. The common
transaction is used to access multiple audited files within the same transaction. At any
time, a process has at most one common transaction.
Nontransactional applications do not require configuration of common transactions.
You may configure common transactions to force the use of automatic transactions for
specific files, even if processes have their own transactions. This capacity is useful
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.)
Note. Do not configure files that were previously audited as COMMONTX, since configuring
such files can cause locking problems.