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BMB versus Freelist Segment: DBMS_SPACE.UNUSED_SPACE and DBA_TABLES.EMPTY_BLOCKS (Doc ID 149516.1)

Last updated on SEPTEMBER 29, 2023

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


This bulletin explains how to interpret the DBA_TABLES.EMPTY_BLOCKS value and DBMS_SPACE.UNUSED_SPACE information regarding FREELIST and BMB (Bit Mapped Block) segments in 9i.


The following examples should help the DBAs not to misunderstand the values returned by different sources of information regarding the space used within blocks.


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