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How to check dictionary and fixed objects statistics (Doc ID 1474937.1)

Last updated on APRIL 14, 2021

Applies to:

Oracle Database - Enterprise Edition - Version to [Release 10.2 to 12.1]
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 Database Cloud Exadata Service - Version N/A and later
Information in this document applies to any platform.
Since version 10 it is recommended to gather statistics on the dictionary and the fixed objects.


This article describes how to check dictionary statistics including statistics on fixed objects. Since version 10g, statistics on the data dictionary are mandatory for the cost-based optimizer to work properly. Dictionary statistics include the statistics on the tables and indexes owned by SYS (and other internal RDBMS schemas like SYSTEM) and the statistics on the fixed objects. Fixed objects are the internal X$ tables and the so called dynamic performance views or V$ views which are based upon them. These are not real tables and indexes, but rather memory structures. The statistics for the fixed objects need to be gathered manually; they are not updated by the automatic statistics gathering.


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