RSC/MP Programming Manual

Application Development Monitoring Transaction Calls
RSC/MP provides a sample makefile, rsctest.mak, which demonstrates the
environment variable method. This makefile can be used to rebuild the rsctest utility
or as a model set of linker options that yo u can use as a starting point and adapt for
use in your own application. If yo u use the same linker options as those used by
rsctest.mak, then the dynamic loader will search for librsc and libpipe in
directories named by standard environment variables as listed in the Remote Server
Call (RSC/MP) Installation and Configuration Guide (Section 5, Installing RSC/MP on
UNIX Workstations).
Monitoring Transaction Calls
The Transaction Management Facility (TMF) subsystem, the major functional
component of the NonStop Transaction Manager/MP product, provides transaction
protection, database consistency, and database recovery.
Fundamental to the TMF subsystem is a TMF transaction, a multi-step operation that
changes your database from one consistent state to another. Specifically, within the
RSC/MP environment, a TMF transaction is one or more RscWrite or RscWriteRead
function calls delimited by a pair of TMF function calls (RscBeginTransaction and
RscEndTransaction, or RscBeginTransaction and RscAbortTransaction).
The TMF subsystem treats each transaction as a single unit, ensuring that either all or
none of the changes that it makes are applied to the database.
For more information about the TMF subsystem, see the TM/MP Introduction.
Using Sessions With TMF Processing
RSC/MP sessions support only one active TMF transaction at a time, and only when
using session type RSC_ST_INTERPROCESS. If the return code
RSC_TRANSACTION_IN_PROGRESS is returned, RSC/MP rejects any attempt to
begin another transaction. It does not matter whether the active transaction was
started explicitly or automatically. If yo u need to perform multiple, concurrent
transactions, you must begin multiple sessions and initiate one transaction per session.
Note. RSC does not support TMF transactions for IDS requesters. You cannot use explicit or
automatic TMF transaction control with the IDS session type (RSC_ST_ID S).
See Section 4, RSC/MP Sessions, for more information about sessions.
Controlling TMF Transactions
Within the RSC/MP environment, you can begin and end TMF transactions explicitly or
implicitly (automatically). Both methods have the same effect. While the explicit method
is easier to program, the implicit method might improve performance because it
requires fewer I/O calls to the host.
You can use explicit and implicit transaction control interchangeably, for successive
transactions or even for a single transaction. For example, you can start a transaction
explicitly and then have it end automatically.
HP NonStop Remote Server Call (RSC/MP) Programming Manual — 522360-006
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