Oracle 参数 AWR_PDB_AUTOFLUSH_ENABLED 官方解释，作用，如何配置最优化建议
本站中文解释
AWR_PDB_AUTOFLUSH_ENABLED是一个自11g开始支持的Oracle参数，它控制Automatic Workload Repository (AWR) 对PDB（容器数据库）的汇报行为。
如果设置为FALSE，PDB中的汇报操作将在主实例的AWR处理完成后，再在PDB中进行一次，此时PDB的汇报行为受主实例的影响。如果设置为TRUE，PDB将自己控制数据库性能报告（如AWR），不受主实例影响，性能报告可能与主实例不同。
为了正确设置AWR_PDB_AUTOFLUSH_ENABLED ，必须考虑应用的业务要求，以及主实例、PDB的意图是否一致。
一般情况下，该参数的设置取决于它们是否在一起使用，如果两个无关系，就不需要连接，所以可以设置为FALSE。必要时，可以将参数设置为TRUE，使主实例和PDB的行为一致，这样可以保证对AWR的一致报告。
官方英文解释
AWR_PDB_AUTOFLUSH_ENABLED enables you to specify whether to enable or disable automatic Automatic Workload Repository (AWR) snapshots for all the PDBs in a CDB or for individual PDBs in a CDB.
| Property | Description |
|---|---|
|
Parameter type |
Boolean |
|
Default value |
|
|
Modifiable |
|
|
Modifiable in a PDB |
Yes |
|
Range of values |
|
|
Basic |
No |
|
Oracle RAC |
The same value must be used on all instances. |
Note:
The value of this parameter in CDB$ROOT (the root of a CDB) has no effect in the root. Automatic AWR snapshots are always enabled in the root, regardless of the setting of this parameter.
The default value of AWR_PDB_AUTOFLUSH_ENABLED is false. Thus, by default, automatic AWR snapshots are disabled for all the PDBs in a CDB.
When you change the value of AWR_PDB_AUTOFLUSH_ENABLED in the CDB root, the new value takes effect in all the PDBs in the CDB.
Therefore, if you change the value of AWR_PDB_AUTOFLUSH_ENABLED in the CDB root to true, the value of AWR_PDB_AUTOFLUSH_ENABLED is also changed to true in all of the PDBs, so that automatic AWR snapshots are enabled for all the PDBs.
You can also change the value of AWR_PDB_AUTOFLUSH_ENABLED in any of the individual PDBs in a CDB, and the value that is set for each individual PDB will be honored. This enables you to enable or disable automatic AWR snapshots for individual PDBs.
When a new PDB is created, or a PDB from a previous database release is upgraded to the current database release, automatic AWR snapshots are enabled or disabled for the PDB based on the current value of AWR_PDB_AUTOFLUSH_ENABLED in the root.
See Also:
-
Oracle Database
Performance Tuning Guide for more information about Automatic Workload Repository (AWR) -
Oracle Database
Performance Tuning Guide for more information about AWR snapshots
