近期发现个别11G数据库无法自动收集统计信息，部分视图查询结果如下：

SQL>  select client_name,status from dba_autotask_client where client_name = ‘auto optimizer stats collection‘;
 
CLIENT_NAME                                                      STATUS
---------------------------------------------------------------- --------
auto optimizer stats collection                                  ENABLED
 
SQL>
 
SQL> select client_name,status from dba_autotask_task;
 
CLIENT_NAME                                                      STATUS
---------------------------------------------------------------- --------
 
SQL>
SQL> select window_name,autotask_status from DBA_AUTOTASK_WINDOW_CLIENTS;
 
WINDOW_NAME                    AUTOTASK_STATUS
------------------------------ ---------------
WEDNESDAY_WINDOW               DISABLED
FRIDAY_WINDOW                  DISABLED
SATURDAY_WINDOW                DISABLED
THURSDAY_WINDOW                DISABLED
TUESDAY_WINDOW                 DISABLED
SUNDAY_WINDOW                  DISABLED
MONDAY_WINDOW                  DISABLED
 
7 rows selected
 

发现作业全部DISABLED，经测试发现和数据库安装时未勾选“启用自动维护任务”的现象一致(默认勾选)，可能是之前ＤＢＡ安装时取消勾选，如下图：

由于未勾选“启用自动维护任务“，数据安装会执行如下命令，导致作业disable：

execute DBMS_AUTO_TASK_ADMIN.disable();

以后数据库如果需要启动自动维护任务，只需要执行如下命令：

SQL> execute DBMS_AUTO_TASK_ADMIN.enable();
 
PL/SQL procedure successfully completed
 
SQL> select window_name,autotask_status from DBA_AUTOTASK_WINDOW_CLIENTS;
 
WINDOW_NAME                    AUTOTASK_STATUS
------------------------------ ---------------
WEDNESDAY_WINDOW               ENABLED
FRIDAY_WINDOW                  ENABLED
SATURDAY_WINDOW                ENABLED
THURSDAY_WINDOW                ENABLED
TUESDAY_WINDOW                 ENABLED
SUNDAY_WINDOW                  ENABLED
MONDAY_WINDOW                  ENABLED
 
7 rows selected
 

解决oracle 11g安装导致数据库无法自动搜集统计信息