How to Effectively Debug Oracle's ORA-01775: Looping Chain of Synonyms?

Debugging ORA-01775: Looping Chain of Synonyms

Despite understanding the ORA-01775 error, debugging it can be daunting, prompting the question of how to trace the issue effectively.

Existing Synonym Definition Query

While manually tracing synonyms can be error-prone, an alternative approach involves querying the schema for the current synonym definition. This can be achieved using the following query:

SELECT synonym_name, table_name, db_link 
FROM user_synonyms 
WHERE synonym_name = 'PUBLIC_SYNONYM_NAME';

Additional Debugging Techniques

To further aid in debugging:

• Trace Files: Enable SQL trace files to capture detailed SQL activity, including synonym resolutions.
• DBMS_UTILITY: Use the DBMS_UTILITY.FORMAT_CALL_STACK procedure to print the stack trace of a recursive call.
• Reversing the Creation Order: Start by dropping the synonym that is causing the loop and progressively create and drop synonyms in reverse order until the error disappears. This can help identify the problematic synonym.

Graphical Tools

Unfortunately, there are no graphical tools specifically designed for debugging looping chains of synonyms in Oracle. However, some general-purpose database management tools may provide enhanced visibility into the schema and object dependencies.

Caveat

It's worth noting that the ORA-01775 error can also occur when a synonym points to a non-existent view or table. This can be a confounding factor and requires additional investigation beyond checking for looping chains.

The above is the detailed content of How to Effectively Debug Oracle's ORA-01775: Looping Chain of Synonyms?. For more information, please follow other related articles on the PHP Chinese website!