Error: LogMiner Fallen Behind Processing Redo Logs

Issue

The following error appears when LogMiner cannot access the required redo log files:

LogMiner Fallen behind processing redo logs

This error typically occurs with one of these Oracle error codes:

• ORA-01291: Missing logfile - Not all log files corresponding to the time or SCN range specified have been added to the list.
• ORA-01292: No log file has been specified for the current LogMiner session.
• ORA-01284: File cannot be opened - The file or directory may not exist or may be inaccessible.

Environment

• Connector: Oracle
• Update method: LogMiner

Resolution

To resolve this issue:

1. Check redo log retention policy: Ensure the retention policy is set to at least 7 days to prevent log files from being deleted while LogMiner still needs them.

2. Verify log file availability: Work with your Oracle DBA to ensure all required redo log files exist and the retention policy covers the entire processing timeframe.

3. Consider migrating to Binary Log Reader: If the issue persists even with proper retention settings, migrate to the Binary Log Reader incremental sync method, which doesn't rely on redo log availability. For more information about migrating to this method, see our Binary Log Reader documentation.

Cause

LogMiner requires access to redo log files to read transaction data. This error occurs when:

• Redo log files are deleted or moved before LogMiner finishes processing them.
• The redo log retention period is too short for the connector's processing speed.
• File system issues prevent access to the log files.
• Network connectivity issues occur in RAC environments.

When any of these conditions are detected, the connector automatically triggers a resync to ensure data consistency.