Oracle教程 2023-02-26

Oracle 参数 DB_INDEX_COMPRESSION_INHERITANCE 官方解释，作用，如何配置最优化建议

本站中文解释

参数

DB_INDEX_COMPRESSION_INHERITANCE参数用于控制指定再继承表空间上索引空间的压缩属性是否继承对象的所有者。

值为TRUE表示只允许在继承表空间上的索引空间继承创建对象的所有者的压缩属性，

值为FALSE表示在继承表空间上的索引空间不会继承创建对象的压缩属性。

正确设置：

ALTER SYSTEM SET DB_INDEX_COMPRESSION_INHERITANCE=TRUE;

官方英文解释

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.

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官方英文解释

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