User Manual

Configuring Automatic Transaction Processing
HP NonStop AutoTMF Software User’s Guide—429952-014
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Transaction File (TFILE)
supports large transfers, it takes advantage of the feature to provide optimum
performance.
NonStop AutoTMF software cannot emulate unstructured writes (either with large or
small transfers) to audited structured files.
Transaction File (TFILE)
The TMF Application Programmers Guide describes the use of the TFILE ($TMP) to
manage multiple transactions in a multi-threaded program. Because NonStop
AutoTMF software also manages multiple transactions and transactions in parallel with
the program transactions, NonStop AutoTMF software opens the TFILE. For this
reason, the TFILE must be managed as a shared resource, even though the TFILE
appears to the program as a dedicated resource.
NonStop AutoTMF software manages TFILE sharing effectively, using the TFILE to
support parallel and nowait automatic transactions, and to manage process
transactions. Your programs can use the TFILE in the conventional manner, but you
are bound by TMF limits on the number concurrent transactions in a single process
described below in Number of concurrent transactions.
Unilateral Aborts
When a program updates audited files within a transaction, an external factor may
cause the transaction to be aborted and uncommitted updates to be rolled back. Such
aborts are called unilateral, because they do not require the cooperation of the process
that started the transaction. Factors causing unilateral aborts include:
•
A process is terminated by another process.
•
A server process that inherits a transaction process (or its CPU) fails before
replying to the transactional request.
•
A server process that inherits a transaction process performs an
ABORTRANSACTION request.
•
A CPU, a primary disk process, or a TMF component fails.
•
A transaction exceeds the system AutoAbort time limit.
•
The TMF operator aborts the transaction.
NonStop AutoTMF software prevents many sources of unilateral aborts and detects
and deals with unilateral aborts that are not preventable. When a unilateral abort does
occur, NonStop AutoTMF software achieves database consistency that is equivalent to
unaudited database consistency by:
•
Intercepting operations that would cause the process to terminate (such as ABEND
or STOP) and committing any outstanding automatic transaction.