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HP Reliable Transaction Router User Manual

Page 95

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transaction

An operation performed on a database, typically causing an

update to the database. Analogous in many cases to a business

transaction such as executing a stock trade or purchasing an

item in a store. A business transaction may consist of one or

more than one RTR transaction. A transaction is classified as

original, replay, or recovery, depending on how it arrives at the

backend:

Original—Transaction arrived on the first attempt from the

client.

Replay—Transaction arrived after some failure as the

result of a re-send from the client (that is, from the client

transaction-replay buffers in the RTRACP).

Recovery—Transaction arrived as the result of a backend-

to-backend recovery operation (recovery from the

journal).

transaction controller

A transaction controller processes transactions. A transaction

controller may have 0 or 1 transactions active at any moment in

time. It is through the transaction controller that messages and

events are sent and received.

transaction ID

Transaction identification created for each transaction by RTR.

transaction state

As a transaction proceeds from initiation to completion, it passes

through several defined states such as SENDING, VOTING,

RECEIVING, and COMMIT. These states are shown, for

example, with the SHOW TRANSACTION command.

transaction voting

A transaction cannot be committed to the database until all

participating servers agree that it is to be committed. This is

part of the two-phase commit process. Once voting is complete

and all servers are in agreement, the transaction proceeds to the

COMMIT state. See voting.

transactional message

A message containing transactional data.

Glossary–11