Oracle Database / Operations & Incident Response
ORA-04021: investigate an object lock timeout during compilation or DDL
A library or object lock timeout can occur when code or metadata is in use. Capture the object name and active workload at the failure time.
Environment and inputs: Oracle Database 19c baseline · SQL*Plus-compatible SQL unless RMAN, DGMGRL, ADRCI or a host shell is specified. Check release, patch level, edition and container first.
Start with this diagnostic
Use the stated SQL, RMAN, DGMGRL or host shell and replace sample names with approved targets. DBA and V$ views need authorized catalog access in the correct container. Do not grant broad privileges for an example.
SELECT session_id, owner, name, type, mode_held, mode_requested FROM dba_ddl_locks WHERE owner = 'APP_OWNER';Read the result
The view provides DDL lock context, but some library-cache relationships need further diagnostics. A completed timeout may leave no current waiter.
Resolve and verify
Correlate compilation, deployment and long-running calls, then coordinate a safe maintenance window or targeted application drain.
Operational precautions
Do not repeatedly recompile the schema or kill every session using the package.