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Compaq AA-Q88CE-TE User Manual

Page 52

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Transaction Management
4.1 Overview

this transaction is removed from memory and can no longer be monitored by the

command.

The RTR

DUMP JOURNAL

command can be used to trace and review the flow of a

transaction. The RTR journal saves all of the information about a transaction,
its transaction journal state, the transaction messages (records) received from the
RTR client, and the content of a message sent to the server. The information will
be kept until a transaction is committed and forgotten.

The RTR

SET TRANSACTION

command is used to modify a live transaction to

change the current state of a transaction to a new state. This command can be
used to circumvent a difficult situation. For example, in a situation where two
shadowed servers are configured, the system administrator might decide not
to replay (recover) all transactions in a shadowed RTR journal after a failure.
The

SET TRANSACTION

command could set specified transactions in a PRI_DONE

or remember state to a DONE state and avoid the delay of transactions being
remembered from a journal for fast recovery. The

SET TRANSACTION

command

should only be used by experienced RTR system administrators as the command
introduces the risk of corrupting or losing transactions if used incorrectly. It can
be used on the backend only and the RTR log file must be turned on for this
command.

Log file entries are made for all transaction state changes for debugging and
auditing purposes.

4.1.0.1 Command Line Examples

An example of the use of the

SET TRANSACTION

command:

RTR> start rtr
RTR> set log/file=settran
RTR> set transaction/state=PRI_DONE/new_state=DONE/facility=Facility1/partition=Partition1 *

This example would set all transactions with the wildcard * in the current state
of PRI_DONE (remember) to DONE on the facility Facility1 and the partition
Partition1. The log file, settran, would record the transaction state changes.
The changes could be viewed with the

SHOW TRANSACTION

command or the

DUMP

JOURNAL

command. In a shadow recovery situation this would clear the journal of

remember transactions and provide for a fast recovery of access to the database if
needed.

For detailed information on these commands see Chapter 6.

4.1.1 Exception Transactions

Transactions can cause servers to fail after the VOTE phase and impact
availability of a server in a recovery. These "EXCEPTION" transactions can
now be flagged by RTR as "fail transactions" after the user sets the attempts
at recovery from a failure with the

SET PARTITION/RECOVERY_RETRY_COUNT=nn

command. They then can be identified and removed from the RTR journal
and from the system to allow recovery to continue with the

SET TRANSACTION

command. In the case of a flagged "EXCEPTION" transaction the system
administrator can take action by changing the state of the "EXCEPTION"
transaction to that of "DONE" with the

SET TRANSACTION/STATE=EXCEPTION

/NEW_STATE=DONE

to allow the recovery to continue.

4–2 Transaction Management