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XA Support
This appendix explains how RTR may be used with a X/OPEN Distributed
Transaction Processing (DTP) conformant Resource Manager.
C.1 Introduction
The X/OPEN Distributed Transaction Processing (DTP) architecture defines
a standard interface that lets application programs share resources provided
by resource managers. The XA interface uses the two-phase commit protocol
to commit transactions, and is a system-level bidirectional interface between
the transaction manager (TM) and the resource manager (RM). In the RTR
environment, RTR is the transaction manager and database software such as
ORACLE8 is the resource manager.
Without XA, an RTR application must deal with replayed transactions after
server recovery delivered with
rtr_mt_msg1_uncertain
; the application has to
check if the traansaction has been committed to the database. With XA, the
application does not need to be concerned with this problem.
The XA library is an external interface that enables a transaction manager to
coordinate global transactions. These can include opening a resource manager,
starting a transaction, rolling back a transaction, preparing and committing a
transaction, and closing a resource manager. With XA, RTR can connect directly
to a resource manager such as ORACLE8.
C.1.1 MONITOR XA
Monitors the internal status of XA interface activities. The command displays
counters containing information such as the number of XA calls, call status
(success or failure), and the number of read-only transactions. Provides counts
for the open, close, start, end, prepare, commit, rollback, and recovery commands.
Command Syntax: MONITOR XA
C.1.2 New Qualifier to CREATE FACILITY Command
The CREATE FACILITY command has a new qualifier that references the defined
resource manager. All resource managers that will be accessed by a facility must
be specified. All transactions to these resource managers are recovered when the
facility is created.
Command Syntax:
CREATE FACILITY facility_name /frontend=... /backend=... /router=...
/resource_manager=(RM_1, RM_2)
where:
XA Support C–1