Materialized View Refresh : Log Population and Purge (Doc ID 236233.1)

Last updated on FEBRUARY 18, 2025

Applies to:

Oracle Database Cloud Service - Version N/A and later
Oracle Database Backup Service - Version N/A and later
Oracle Database - Enterprise Edition - Version 8.1.7.4 and later
Oracle Database Cloud Schema Service - Version N/A and later
Gen 1 Exadata Cloud at Customer (Oracle Exadata Database Cloud Machine) - Version N/A and later
Information in this document applies to any platform.

Purpose

The purpose of this article is to explain Oracle's materialized view fast
refresh mechanism. It also discusses the performance, problems related to
materialized view log management.

NB: The terms Snapshot and Materialized View are synonymous.

Scope

This is for customers of all levels of expertise in dealing with materialized views.

Details

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In this Document

1. FAST REFRESH

1.1 DATABASE OBJECTS INVOLVED IN THE FAST REFRESH MECHANISM

1.1.1 What does an MView consists of

1.1.2 What does an MView log on a master table consists of

1.1.3 An AFTER ROW trigger on the master table named TLOG$_<table_name>

1.2 REGISTRATION

1.3 FAST REFRESH OPERATION

2. MVIEW LOG MANAGEMENT

2.1 WHEN MVIEW LOG ENTRIES CAN BE PURGED?

2.1.1. HOW FAST REFRESH IS PERFORMED AND WHEN THE MVIEW LOG GETS PURGED

2.1.2 COMPLETE REFRESH

2.1.3 PURGE PROBLEMS

2.2 MANAGING MVIEW LOG SPACE

2.2.1 TRUNCATING A MVIEW LOG

2.2.2 REORGANIZING MASTER TABLES THAT HAVE MVIEW LOGS

3. RELATED BUGS

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