Truncating the transaction log

The Mirror Replication Agents for ASE and Oracle support both automatic and manual transaction log truncation.

You can enable or disable automatic log truncation at any time, and you can truncate the Mirror Replication Agent transaction log manually at any time, with automatic log truncation either enabled or disabled.

When the Mirror Replication Agent truncates its transaction log, either automatically or on command (manually), the truncation point is determined by the most recent LTM Locator received from the primary Replication Server.

You have two options for automatic transaction log truncation:

• Automatic truncation each time the Mirror Replication Agent receives a new LTM Locator value from the primary Replication Server

• Periodic truncation on a time interval you specify

Mirror Replication Agent truncates the transaction log based on the most recent truncation point received from the primary Replication Server. The truncation point is part of the information contained in the LTM Locator.

1. Log in to the Mirror Replication Agent instance with the administrator login.

2. Use the ra_config command to enable automatic log truncation and specify the type of automatic truncation:

   • Use the following commands to enable automatic log truncation at a specified time interval:

     ra_config truncation_type, interval
     

     ra_config truncation_interval, N
     

     Here, N is the number of minutes between automatic truncations.

     The maximum truncation_interval value is 720.

   • Use the following command to enable automatic log truncation whenever the Mirror Replication Agent receives a new LTM Locator value from the primary Replication Server:

     ra_config truncation_type, locator_update
     

See the Mirror Replication Agent Reference Manual for more information about the truncation_interval and truncation_type configuration parameters.

1. Log in to the Mirror Replication Agent instance with the administrator login.

2. Use the ra_config command to disable automatic log truncation:

   ra_config truncation_type, command
   

If automatic log truncation is disabled, you must periodically truncate the Mirror Replication Agent transaction log manually.

1. Log in to the Mirror Replication Agent instance with the administrator login.

2. Use the following command to truncate the Mirror Replication Agent transaction log:

   pdb_truncate_xlog
   

   The pdb_truncate_xlog command is asynchronous; it does not return success or failure, unless an immediate error occurs.

See the Mirror Replication Agent Reference Manual for more information about the pdb_truncate_xlog command.