CDC Guide for Linux, UNIX, and Windows

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Starting the PowerExchange Logger

You can cold start, warm start, or special start a PowerExchange Logger process.

You must start the PowerExchange Logger under a user ID that has READ and WRITE access to PowerExchange Logger log files. Also, the PowerExchange Listener must be running under a user ID that READ access to the PowerExchange Logger log files.

Choose the start method that is appropriate for your current situation:

A cold start
uses the restart and sequence tokens, if present, in the pwxccl configuration file to determine the point in the change stream from which the PowerExchange Logger starts reading changes. If you are starting the PowerExchange Logger for the first time, you must perform a cold start. When you enter the pwxccl command to start the PowerExchange Logger, set the coldstart parameter to Y.

A warm start
uses the restart and sequence tokens in the CDCT file to resume CDC processing. You can perform a warm start only if you have run the PowerExchange Logger previously and have a recent CDCT file for the database instance. When you enter the pwxccl command for starting the PowerExchange Logger, set the coldstart parameter to N or omit the parameter.

A special start
uses the restart and sequence tokens in the pwxccl.cfg file to override the token values from the CDCT file for the PowerExchange Logger run. None of the data that was captured prior to the special start is lost. You must enter the SEQUENCE_TOKEN and RESTART_TOKEN parameters in the pwxccl.cfg. The SEQUENCE_TOKEN value must be greater than or equal to the sequence token in the CDCT file.

Use a special start to avoid capturing changes from problematic portions of the logs. For example, perform a special start in the following situations:

You do not want the PowerExchange Logger to capture an upgrade of an Oracle catalog. In this case, stop the PowerExchange Logger before the upgrade. After the upgrade is complete, generate new sequence and restart tokens for the PowerExchange Logger based on the post-upgrade SCN. To perform a special start, you must specify the SEQUENCE_TOKEN and RESTART_TOKEN parameters in the pwxccl.cfg file. Then special start the PowerExchange Logger.

You do not want the PowerExchange Logger to reprocess old, unavailable logs that were caused by outstanding UOWs that are not of CDC interest. In this case, stop the PowerExchange Logger. Edit the RESTART_TOKEN value to reflect the SCN of the earliest available log, and then perform a special start. If any of the outstanding UOWs are of CDC interest, data might be lost.

You cannot use the pwxcmd or infacmd program to start the PowerExchange Logger.

PowerExchange Logger for Linux, UNIX, and Windows

PWXCCL Syntax and Parameters

How the PowerExchange Logger Determines the Start Point for a Cold Start

Cold Starting the PowerExchange Logger

How the PowerExchange Logger Determines the Start Point for a Cold Start

Cold Starting the PowerExchange Logger

PWXCCL Command Parameters

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