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Fix A Huge Materialized View Log With TRUNCATE In Case Regular DBMS_MVIEW.PURGE Fails (Doc ID 1594739.1)

Last updated on FEBRUARY 21, 2024

Applies to:

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


 A Materialized View Log (MVIEW LOG) may have grown in size to a point where deleting rows may exceed available UNDO space or fail for other reasons.

Such situations can also lead to an unused, but still registered MVIEW to not unregister, but instead cause UNDO space exhaustion.

The goal of this article is to show how such an MVIEW LOG can be truncated properly.

The straight-forward approach to simply TRUNCATE the MVIEW LOG may lead to missed change vectors if the truncate operations occurs concurrently to source table updates (that is to say, tables that the MVIEW references).


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