🧩 ORA-00600 in RAC Environments

 🧩 Introduction

ORA-00600 in a RAC (Real Application Clusters) setup indicates that an internal consistency check has failed on one of the nodes. These errors are serious and can affect a single node or propagate to multiple nodes, potentially impacting application availability. Diagnosing ORA-00600 in RAC requires analyzing arguments, node information, and trace files to determine the cause.

Error Message Example:

ORA-00600: internal error code, arguments: [kghh001], [456], [NULL], ...

The alert log and trace files will specify the node and process affected.

Common Causes in RAC

Bugs in Oracle RAC inter-node communication or cache fusion.

Memory corruption in SGA or PGA on a specific node.

Problematic SQL, DML, or PL/SQL execution affecting shared resources.

Differences in patch levels or OS libraries across nodes.

Data block or index corruption visible only in cluster operations.

Step 1: Identify the Node and Process

Check alert logs for each RAC node to locate the error occurrence. Note the session or process affected.

Step 2: Review Trace Files

Trace files provide stack information and the SQL context. Locate trace files at:

$ORACLE_BASE/diag/rdbms/<db_name>/<SID>/trace

Pay special attention to RAC-specific modules like kghf or lgwr.

Step 3: Analyze Error Arguments

Use the first argument in ORA-00600 to search Oracle Support for known bugs or patches. RAC-related bugs may require cluster-wide fixes.

Step 4: Apply Fixes or Workarounds

Apply Oracle patches recommended for the ORA-00600 argument.

Correct or tune SQL/PLSQL causing the error.

Reboot affected nodes if memory corruption is suspected.

Rebuild corrupted objects or segments if necessary.

Step 5: Prevent Recurrence

Maintain consistent patch levels and OS libraries across nodes.

Monitor memory usage on each RAC instance.

Use Oracle health checks and RAC diagnostics regularly.

Conclusion

ORA-00600 errors in RAC environments are critical but manageable. Proper trace analysis, coordination with Oracle Support, and proactive RAC monitoring ensure high availability and database stability.