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How to Troubleshoot Slow Materialized View Complete Refresh Issues (Doc ID 1313291.1)

Last updated on SEPTEMBER 29, 2021

Applies to:

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

Purpose

This article describes how to troubleshoot slow materialized view complete refresh in order to find the cause of the slowness, and it provides directions towards the solution.

In simplified terms complete refresh consists of the following phases:


Several internal/recursive SQLs are involved in the above mentioned phases.

Troubleshooting Steps

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In this Document
Purpose
Troubleshooting Steps
 1./ Has the complete refresh or any of its parts ever performed better?
 2./ Which internal/recursive SQL(s) is (are) the most time consuming
 2.1./ DELETE FROM mview is slow
 2.2./ INSERT INTO mview SELECT ... is slow
 2.3./ SQLs on MLOG$_masterTable tables is slow
References

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