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Master Note: Overview for SCN issues (Doc ID 1503937.1)

Last updated on DECEMBER 26, 2019

Applies to:

Oracle Database - Enterprise 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
Oracle Database Exadata 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.


As the January 2012 CPU (and associated PSU) releases include some SCN related bug fixes, along with other recommended fixes, this document will provide some information about the System Change Number (SCN) and related issues.


This document is intended for Oracle DBAs.


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In this Document
 What is System Change Number (SCN)?
 What is SCN Headroom?
 Checking the SCN Limit
 What is this "_external_scn_rejection_threshold_hours" parameter?
 Documents and Patches Related to the SCN Issue

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