修改初始化参数awr_pdb_autoflush_enabled

数据库版本：19C

AWR_PDB_AUTOFLUSH_ENABLED：指定是否为CDB中的所有PDB或CDB中的单个PDB启用或禁用自动工作负载存储库(AWR)快照

以下为将参数由false修改为true的实际操作过程：

问题：在pdb级别与cdb级别修改此参数有什么不同？

验证：pdb级别修改awr_pdb_autoflush_enabled参数

SQL> alter session set container=mypdb2;

Session altered.

SQL> alter system set awr_pdb_autoflush_enabled=true;

System altered.

SQL> show parameter awr_pdb_autoflush_enabled

NAME                                 TYPE        VALUE

------------------------------------ ----------- ------------------------------

awr_pdb_autoflush_enabled            boolean     TRUE

SQL> conn / as sysdba

Connected.

SQL> show parameter awr_pdb_autoflush_enabled

NAME                                 TYPE        VALUE

------------------------------------ ----------- ------------------------------

awr_pdb_autoflush_enabled            boolean     FALSE

SQL> alter session set container=mypdb2;

Session altered.

SQL> alter system set awr_pdb_autoflush_enabled=false;

System altered.

结论：pdb级别修改awr_pdb_autoflush_enabled参数，只会影响该pdb.

验证：cdb级别修改awr_pdb_autoflush_enabled参数

SQL> conn / as sysdba

Connected.

SQL> alter pluggable database all open;

Pluggable database altered.

SQL> alter system set awr_pdb_autoflush_enabled=true;

System altered.

SQL> show pdbs

   CON_ID CON_NAME                       OPEN MODE  RESTRICTED

---------- ------------------------------ ---------- ----------

        2 PDB$SEED                       READ ONLY  NO

        3 MYPDB2                         READ WRITE NO

        4 ORCLPDB3                       READ WRITE NO

        5 PDBC                           READ WRITE NO

SQL> alter session set container=ORCLPDB3;

Session altered.

SQL> show parameter awr_pdb_autoflush_enabled

NAME                                 TYPE        VALUE

------------------------------------ ----------- ------------------------------

awr_pdb_autoflush_enabled            boolean     TRUE

SQL> conn / as sysdba

Connected.

SQL> alter session set container=pdbc;

Session altered.

SQL> show parameter awr_pdb_autoflush_enabled

NAME                                 TYPE        VALUE

------------------------------------ ----------- ------------------------------

awr_pdb_autoflush_enabled            boolean     TRUE

SQL> conn / as sysdba

Connected.

SQL> alter session set container=mypdb2;

Session altered.

SQL> show parameter awr_pdb_autoflush_enabled

NAME                                 TYPE        VALUE

------------------------------------ ----------- ------------------------------

awr_pdb_autoflush_enabled            boolean     FALSE

结论：cdb级别修改awr_pdb_autoflush_enabled，会影响所有pdb.

前提是不要单独进入某个pdb修改该参数，否则不受cdb级别管控.

如上所示pdb mypdb2该参数的值依然是FALSE.