Compaq AA-Q88CE-TE Transaction Management Overview, Exception Transactions, Command Line Examples

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.

4–2Transaction Management