User Manual

Configuring Automatic Transaction Processing
HP NonStop AutoTMF Software User’s Guide—429952-014
4-19
Limitations
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
program; this requirement is usually satisfied by the program’s initialization
routines that OPEN $RECEIVE to read the startup message. If a procedure that
requires a file number is called prior to the first call to OPEN, the program will trap
because the NonStop AutoTMF data structures have not been allocated.
•
When calling I/O procedures such as READ and WRITE, a program must use a file
number that was obtained from a call to OPEN or FILE_OPEN_. Programs that
assume that the file system allocates file numbers serially (and uses hard coded
file numbers) will not function correctly. Programs can, however, assume that
$RECEIVE will have file number zero.
SQL tables
NonStop AutoTMF software does not currently support the generation of automatic
transactions to access SQL tables.
Number of concurrent transactions
The NonStop AutoTMF software runtime opens the TFILE to manage multiple,
concurrent, automatic transactions. The number of concurrent transactions allowed for
each process depends on the version of the NonStop OS:
•
One hundred (100) transactions on systems running versions of the NonStop OS
prior to G06.20. It is also the NonStop AutoTMF software default.
•
Up to 1000 transactions on systems running the NonStop OS version G06.20 or
later. To allow more than the default 100 transactions, you must configure the
ATMFMAXTX global parameter or set the program attribute MAXTX.