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How to Analyze Library Cache Timeout with Associated: ORA-04021 'timeout occurred while waiting to lock object %s%s%s%s%s.' Errors (Doc ID 1486712.1)

Last updated on AUGUST 21, 2023

Applies to:

Oracle Database - Standard Edition - Version and later
Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata Express Cloud Service - Version N/A and later
Gen 1 Exadata Cloud at Customer (Oracle Exadata Database Cloud Machine) - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Information in this document applies to any platform.


This Document discusses library cache locks and pins and how to analyze locking problems in this area.

Troubleshooting Steps

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In this Document
Troubleshooting Steps
 Why does ORA-4021 error occur?
 Which views can be used to detect library locking problems?
 How to find out why an ORA-4021 occurs?
 What type of objects can be locked in a library cache?
 Which lock/pin mode is required for which type of action?
 Common ora-4021 and ora-4020 situations
 Known issues:

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