ORA-04020 Deadlocks: Most Common Causes (Doc ID 166924.1)

Last updated on NOVEMBER 08, 2024

Applies to:

Oracle Database Exadata Express Cloud Service - Version N/A and later
Oracle Database Cloud Service - Version N/A and later
Oracle Database Backup Service - Version N/A and later
Oracle Database Cloud Exadata Service - Version N/A and later
Oracle Database - Personal Edition - Version 7.3.4.0 and later
Information in this document applies to any platform.

Purpose

This document outlines the most common scenarios for ORA-04020 Deadlocks and how to avoid them.

Troubleshooting Steps

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In this Document

Troubleshooting Steps

Reasons for getting a ORA-04020 error

1. Self-Deadlocks

The recompilation of a trigger can sometimes result in an ORA-04020

Compiling circular dependent code

ORA-4020 self deadlock on drop table with a functional index

ORA-04020 when creating functional indexes due to the usage of %TYPE

ALTER TABLE Command Fails Using INDEX ONLINE Option

DBCA scripts contain an error "ORACLE_SID PIPPO" instead of correct "ORACLE_SID=PIPPO".

Truncating a synonym raises an ORA-04020 "deadlock detected" rather than an ora-942 "invalid table or view".

2. Deadlocks between concurrent sessions

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