DB_INDEX_COMPRESSION_INHERITANCE

DB_INDEX_COMPRESSION_INHERITANCE dictates how index creation inherits compression attributes.

Property	Description
Parameter type	String
Syntax	DB_INDEX_COMPRESSION_INHERITANCE = { TABLESPACE | TABLE | ALL | NONE }
Default value	NONE
Modifiable	ALTER SESSION, ALTER SYSTEM
Modifiable in a PDB	Yes
Basic	No
Oracle RAC	You must set this parameter for every instance, and multiple instances must have the same value.

Values:

• TABLESPACE

  Index inheritance is based on tablespace attributes.

• TABLE

  Index inheritance is based on table attributes.

• ALL

  Index inheritance is based on table settings. However, if the table does not have default compression attributes, then index inheritance is based on tablespace attributes.

• NONE

  There is no index inheritance from the table or tablespace.

If the CREATE INDEX statement specifies compression attributes, then the value of DB_INDEX_COMPRESSION_INHERITANCE is ignored, and there is no inheritance from the table or tablespace. When there is table inheritance or tablespace inheritance (and the tablespace does not have an explicit index compression clause), then the following matrix is used:

Table/Tablespace Level Compression	Inherited Compression for Index
OLTP	ADVANCED LOW
QUERY LOW, QUERY HIGH	ADVANCED HIGH
ARCHIVE LOW, ARCHIVE HIGH	ADVANCED HIGH

Note: The value of DB_INDEX_COMPRESSION_INHERITANCE is ignored when creating an index owned by SYS. Such indexes do not inherit index compression attributes from tables or tablespaces. If you want to compress an index owned by SYS, you must explicitly specify the index compression attributes in the CREATE INDEX or ALTER INDEX statement.

See Also: Oracle AI Database Administrator’s Guide for more information about index compression