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Oracle ORA-06507 Error: Causes and Solutions Complete Guide

#oracle #database #dba #sql

ORA-06507: PL/SQL Could Not Find Program Unit Being Called

ORA-06507 occurs when the PL/SQL runtime engine cannot locate the program unit (procedure, function, or package) being called during execution. This typically happens when the referenced object has been dropped, invalidated, or is inaccessible due to privilege or schema issues. Understanding the root cause quickly is critical because this error can halt business-critical processes in production environments.

Top 3 Causes and Fixes

Cause 1: INVALID or Missing Program Unit

The most common cause is that the target PL/SQL object has become INVALID due to a dependency change, or has been accidentally dropped.

Diagnosis:

-- Check for INVALID objects
SELECT owner, object_name, object_type, status
FROM   dba_objects
WHERE  status = 'INVALID'
  AND  object_type IN ('PROCEDURE','FUNCTION','PACKAGE','PACKAGE BODY')
ORDER BY owner, object_name;
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Fix — Recompile the invalid object:

-- Recompile individual objects
ALTER PROCEDURE my_schema.my_procedure COMPILE;
ALTER PACKAGE   my_schema.my_package   COMPILE BODY;

-- Recompile all invalid objects in a schema (parallel)
EXEC UTL_RECOMP.RECOMP_PARALLEL(4, 'MY_SCHEMA');
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Check compilation errors if still INVALID:

SELECT line, position, text
FROM   user_errors
WHERE  name = 'MY_PROCEDURE'
ORDER BY sequence;
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Cause 2: Schema Mismatch or Broken Synonym

If the calling code relies on a PUBLIC or PRIVATE SYNONYM that points to the wrong schema or a dropped object, Oracle cannot resolve the program unit at runtime.

Diagnosis:

-- Verify synonym target
SELECT synonym_name, table_owner, table_name
FROM   dba_synonyms
WHERE  synonym_name = 'MY_PROCEDURE';

-- Confirm actual object location
SELECT owner, object_name, object_type, status
FROM   dba_objects
WHERE  object_name = 'MY_PROCEDURE';
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Fix — Recreate the synonym with the correct target:

-- Drop and recreate the public synonym
DROP PUBLIC SYNONYM my_procedure;
CREATE PUBLIC SYNONYM my_procedure FOR correct_schema.my_procedure;
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Best practice — use explicit schema qualification in PL/SQL:

BEGIN
  correct_schema.my_procedure(p_input => 'TEST');
END;
/
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Cause 3: Missing EXECUTE Privilege (Role-Based Grant Issue)

Oracle PL/SQL does not honor privileges granted through roles at runtime. If EXECUTE was granted via a role rather than directly to the user, the PL/SQL engine cannot see the permission and raises ORA-06507.

Diagnosis:

-- Check direct EXECUTE privileges
SELECT grantee, owner, table_name, privilege
FROM   dba_tab_privs
WHERE  table_name = 'MY_PROCEDURE'
  AND  privilege  = 'EXECUTE';
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Fix — Grant EXECUTE directly to the user:

-- Direct grant (not through a role)
GRANT EXECUTE ON my_schema.my_procedure TO target_user;
GRANT EXECUTE ON my_schema.my_package   TO target_user;
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Verify the fix:

BEGIN
  my_schema.my_procedure('VERIFY');
  DBMS_OUTPUT.PUT_LINE('Success');
EXCEPTION
  WHEN OTHERS THEN
    DBMS_OUTPUT.PUT_LINE(SQLERRM);
END;
/
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Quick Fix Checklist

Step Action
1 Query dba_objects for INVALID status
2 Run UTL_RECOMP.RECOMP_PARALLEL after any DDL change
3 Verify synonyms point to the correct schema
4 Grant EXECUTE directly — never rely on roles inside PL/SQL
5 Check user_errors for underlying compilation failures

Prevention Tips

1. Automate INVALID Object Detection
Schedule a daily job using DBMS_SCHEDULER to query dba_objects for INVALID PL/SQL units and alert the DBA team immediately. Always run UTL_RECOMP as part of your DDL deployment runbook.

-- Schedule a monitoring check
SELECT COUNT(*) FROM dba_objects
WHERE status = 'INVALID'
  AND object_type IN ('PROCEDURE','FUNCTION','PACKAGE','PACKAGE BODY');
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2. Standardize Direct EXECUTE Grants in Deployment Scripts
Include explicit GRANT EXECUTE statements in every deployment package. Never depend on role-based grants for PL/SQL inter-object calls, and document all privilege dependencies alongside your code.

Related Errors

  • ORA-04068 — Package state discarded; occurs when a package is recompiled while an active session holds its state.
  • ORA-06550 — PL/SQL compilation error; often precedes ORA-06507 when the unit cannot be found at parse time.
  • ORA-00942 — Table or view does not exist; can invalidate dependent PL/SQL objects leading to ORA-06507.
  • ORA-01031 — Insufficient privileges; closely related when EXECUTE rights are missing.

📖 Want a more detailed guide?
Check out the full in-depth version (Korean) on oraerror.com — includes detailed analysis, additional SQL examples, and prevention tips.

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