HP Integrity NonStop J-Series - Manual (Page 67)

Configuring Automatic Transaction Processing
HP NonStop AutoTMF Software User’s Guide—429952-017
4-19
Automatic Transaction Limitations
TXTIMEOUT is set as follows:

value: n [ SEC[ONDS] | MIN[UTES] ], between 5 and 510 minutes.
value overrides the TMF AutoAbort timer setting. A value entered as n SEConds is
rounded up to minutes.

NEVER: the transactions is never aborted by TMF due to a timeout.

OFF: the default, specifies that the TMF AutoAbort is in effect.
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.
Automatic Transaction Limitations
Program Logic

A program must make one call to OPEN or to FILE_OPEN_ before any procedure
call 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 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 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. However, programs can always assume
that $RECEIVE has the file number zero.
SQL tables
AutoTMF does not currently support the generation of automatic transactions
accessing SQL tables.
Number of concurrent transactions
The AutoTMF 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:

A maximum of one hundred (100) concurrent transactions prior to OS version
G06.20. It is also the AutoTMF default.