HP Reliable Transaction Router - Manual (Page 21)

RTR Terminology
Clients send messages to servers to ask that a piece of work be
done. Such requests may be bundled together into transactions.
An RTR transaction consists of one or more messages that have
been grouped together by a client application, so that the work
done as a result of each message can be undone completely, if
some part of that work cannot be done. If the system fails or is
disconnected before all parts of the transaction are done, then
the transaction remains incomplete.
Transaction
A transaction is a piece of work or group of operations that
must be executed together to perform a consistent transformation
of data. This group of operations can be distributed across many
nodes serving multiple databases. Applications use services that
RTR provides.
Because typically a transaction consists of several operations, a
system or network failure at any step in the process will cause
the transaction to be in doubt. RTR ensures that all transactions
have the ACID properties so that all transactions are in a known
state. (See the description of ‘‘Transactional messaging’’ for
further clarification of transaction integrity.)
Transaction
Controller
With the C++ API, the Transaction Controller manages
transactions (one at a time), channels, messages, and events.
Transactional
messaging
RTR provides transactional messaging in which transactions
are enclosed in messages controlled by RTR.
Transactional messaging ensures that each transaction is
complete, and not partially recorded. For example, a transaction
or business exchange in a bank account might be to move money
from a checking account to a savings account. The complete
transaction is to remove the money from the checking account
and add it to the savings account.
A transaction that transfers funds from one account to another
consists of two individual updates: one to debit the first account,
and one to credit the second account. The transaction is not
complete until both actions are done. If a system performing
this work goes down after the money has been debited from the
checking account but before it has been credited to the savings
account, the transaction is incomplete.
Introduction 1–9