Oracle教程 2023-02-26

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

本站中文解释

COMPATIBLE参数指定数据库的兼容性级别，是一个关键的参数，可以很大程度的影响到数据库的性能、安全性和稳定性。

设置COMPATIBLE参数的步骤如下：

1）查看当前的COMPATIBLE参数的值：

SELECT name, value FROM v$parameter WHERE name = ‘compatible’;

2）如果当前的值比需要的值低，可以用ALTER SYSTEM SET SESSION command调整COMPATIBLE参数：

ALTER SYSTEM SET COMPATIBLE=’18.0.0′ SCOPE=spfile;

3）重新启动数据库，可以使用重启推荐步骤通过SQL Plus 。

4）最后检查COMPATIBLE是否已经被正确设置：

SELECT name, value FROM v$parameter WHERE name = ‘compatible’;

官方英文解释

COMPATIBLE enables you to use a new release of Oracle while ensuring the ability to downgrade the database to an earlier release.

Property	Description
Parameter type	String
Syntax	`COMPATIBLE =` `release_number`
Default value	`21.0.0`
Modifiable	No
Modifiable in a PDB	No
Range of values	`12.2.0` to default release Values must be specified as at least three decimal numbers with each pair separated by a dot, such as `21.0.0` or `21.0.0.0.0`
Basic	Yes
Oracle RAC	Multiple instances must have the same value.

The COMPATIBLE parameter specifies the Oracle version number that the database disk format must be compatible with. The database can be downgraded to the version specified in the COMPATIBLE parameter or any later version.

Setting COMPATIBLE ensures that new features do not write data formats or structures to disk that are not compatible with the earlier release, preventing a future downgrade. Features that require a higher value of COMPATIBLE to work correctly may be restricted or disabled to ensure downgrades are possible.

Typically, users keep COMPATIBLE unchanged when upgrading their Oracle software. After upgrade, users will run the new release of the Oracle software for a few weeks to ensure that the new release is working correctly. Afterwards, users can choose to update COMPATIBLE to the latest version to take advantage of the new features.

Notes:

The value of the COMPATIBLE parameter can be increased to a higher version, but it can never be decreased to a lower version.
The value of the COMPATIBLE parameter should not be changed for a Release Update (RU) or Release Update Revision (RUR). For example, assume you are running Oracle Database 21c and the value of COMPATIBLE is 21.0.0. You then apply Oracle Database Release Update 21.4.0.0.0. Do not set the value of COMPATIBLE to 21.4.0; leave it set to 21.0.0.
When using a standby database, this parameter must have the same value on both the primary and standby databases.

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官方英文解释

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