Oracle 11G统计信息自动收集及调整

Oracle 11G统计信息自动收集及调整

2018-08-08阅读 4850

 

从Oracle 11G开始，数据库统计信息的自动收集被整合到自动维护任务中，满足大多数情形下的运行需求。但对于在线商城，交易系统而言，可能需要调整其执行时间或者自行指定收集窗口。本文描述了如何查看以及调整自动收集统计时间窗口等，供大家参考。

一、缺省的统计信息相关状态查看

1、查看自动收集统计信息对应的task(也就是program的名称)及状态
        --当前状态
        SQL> select * from v$version where rownum<2;

        BANNER
        --------------------------------------------------------------------------------
        Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production

        --如下查询表明统计信息的收集是位于gather_stats_prog这个task，当前状态为enabled，即启用
        SELECT client_name,task_name, status
        FROM dba_autotask_task
        WHERE client_name = 'auto optimizer stats collection';

        CLIENT_NAME                         TASK_NAME              STATUS
        ----------------------------------- ---------------------- --------
        auto optimizer stats collection     gather_stats_prog      ENABLED

        --下面查询dba_scheduler_programs
        --在scheduler_programs中，程序GATHER_STATS_PROG调用
        --dbms_stats.gather_database_stats_job_proc来实现统计信息的自动收集，如下查询
        SQL> SELECT program_action, number_of_arguments, enabled
          2  FROM dba_scheduler_programs
          3  WHERE owner = 'SYS'
          4  AND program_name = 'GATHER_STATS_PROG';

        PROGRAM_ACTION                             NUMBER_OF_ARGUMENTS ENABL
        ------------------------------------------ ------------------- -----
        dbms_stats.gather_database_stats_job_proc                    0 TRUE

2、查看自动收集统计信息是否开启
        SELECT CLIENT_NAME,
               STATUS
        FROM   DBA_AUTOTASK_CLIENT
        WHERE  CLIENT_NAME = 'auto optimizer stats collection';

        CLIENT_NAME                         STATUS
        ----------------------------------- --------
        auto optimizer stats collection     ENABLED

3、统计信息收集的窗口组，如下查询
        SQL> SELECT window_group
          2  FROM dba_autotask_client
          3  WHERE client_name = 'auto optimizer stats collection';

        WINDOW_GROUP
        ----------------------------------------------------------------
        ORA$AT_WGRP_OS

4、查询统计信息收集的具体窗口
        --统计信息收集的时间窗口
        --如下查询周一至周五时间为22点，周六日为6点
        --此外持续也不相同，周一至周五为4小时，周六日为20个小时
        --enabled为true表明当前的这些作业处于激活状态
        SELECT w.window_name,
               w.repeat_interval,
               w.duration,
               w.enabled
          FROM dba_autotask_window_clients c, dba_scheduler_windows w
         WHERE c.window_name = w.window_name AND c.optimizer_stats = 'ENABLED';

        WINDOW_NAME               REPEAT_INTERVAL                DURATION                  ENABL
        ------------------------- ------------------------------ ------------------------- -----
        MONDAY_WINDOW             freq=daily;byday=MON;byhour=22 +000 04:00:00             TRUE
                                  ;byminute=0; bysecond=0

        TUESDAY_WINDOW            freq=daily;byday=TUE;byhour=22 +000 04:00:00             TRUE
                                  ;byminute=0; bysecond=0

        WEDNESDAY_WINDOW          freq=daily;byday=WED;byhour=22 +000 04:00:00             TRUE
                                  ;byminute=0; bysecond=0

        THURSDAY_WINDOW           freq=daily;byday=THU;byhour=22 +000 04:00:00             TRUE
                                  ;byminute=0; bysecond=0

        FRIDAY_WINDOW             freq=daily;byday=FRI;byhour=22 +000 04:00:00             TRUE
                                  ;byminute=0; bysecond=0

        SATURDAY_WINDOW           freq=daily;byday=SAT;byhour=6; +000 20:00:00             TRUE
                                  byminute=0; bysecond=0

        SUNDAY_WINDOW             freq=daily;byday=SUN;byhour=6; +000 20:00:00             TRUE
                          byminute=0; bysecond=0

4、查看自动收集统计信息历史执行情况
        SELECT *                              --Author : Leshami
          FROM dba_autotask_client_history    --Blog   : http://blog.csdn.net/leshami
         WHERE client_name LIKE '%stats%';

二、统计信息收集调度时间禁用及修改

1、启用自动收集统计信息
        BEGIN
           DBMS_AUTO_TASK_ADMIN.ENABLE (
              client_name   => 'auto optimizer stats collection',
              operation     => NULL,
              window_name   => NULL);
        END;

2、禁用自动收集统计信息
        BEGIN
           DBMS_AUTO_TASK_ADMIN.DISABLE (
              client_name   => 'auto optimizer stats collection',
              operation     => NULL,
              window_name   => NULL);
        END;

        --执行上面的代码后，验证是否被禁用
        SELECT CLIENT_NAME,
               STATUS
        FROM   DBA_AUTOTASK_CLIENT
        WHERE  CLIENT_NAME = 'auto optimizer stats collection';

        CLIENT_NAME                         STATUS
        ----------------------------------- --------
        auto optimizer stats collection     DISABLED

3、关闭单个调度时间窗口
        BEGIN
           DBMS_AUTO_TASK_ADMIN.disable (
              client_name   => 'auto optimizer stats collection',
              operation     => NULL,
              window_name   => 'MONDAY_WINDOW');
        END;
        /

        --验证关闭情况，如下，optimizer_stats列为DISABLED
        SQL>   SELECT window_name,
          2           window_next_time,
          3           window_active,
          4           optimizer_stats
          5      FROM dba_autotask_window_clients
          6     WHERE window_name = 'MONDAY_WINDOW'
          7  ORDER BY window_next_time;

        WINDOW_NAME               WINDOW_NEXT_TIME                     WINDO OPTIMIZE
        ------------------------- ------------------------------------ ----- --------
        MONDAY_WINDOW             27-MAR-17 10.00.00.000000 PM PRC     FALSE DISABLED

4、关闭所有时间调度窗口，验证略
        BEGIN
           DBMS_AUTO_TASK_ADMIN.disable (
              client_name   => 'auto optimizer stats collection',
              operation     => NULL,
              window_name   => NULL);
        END;
        /

5、开启单个调度时间窗口及所有时间调度窗口，只需要使用enable过程
        -- 注：单个应指定窗口名字，如window_name   => 'MONDAY_WINDOW'
        BEGIN
           DBMS_AUTO_TASK_ADMIN.enable (
              client_name   => 'auto optimizer stats collection',
              operation     => NULL,
              window_name   => NULL);
        END;
        /

6、修改时间窗口到特定的时间
        --如下示例，将周五时间窗口时间到晚间23点30分
        BEGIN
           DBMS_SCHEDULER.DISABLE (name => '"SYS"."FRIDAY_WINDOW"', force => TRUE);
        END;

        BEGIN
           DBMS_SCHEDULER.SET_ATTRIBUTE (
              name        => '"SYS"."FRIDAY_WINDOW"',
              attribute   => 'REPEAT_INTERVAL',
              VALUE       => 'FREQ=WEEKLY;BYDAY=FRI;BYHOUR=23;BYMINUTE=30;BYSECOND=0');
        END;

        BEGIN
           DBMS_SCHEDULER.ENABLE (name => '"SYS"."FRIDAY_WINDOW"');
        END;

        --验证修改
        SELECT w.window_name,
               w.repeat_interval,
               w.duration,
               w.enabled
        FROM   dba_autotask_window_clients c, dba_scheduler_windows w
        WHERE      c.window_name = w.window_name
               AND c.optimizer_stats = 'ENABLED'
               AND c.window_name = 'FRIDAY_WINDOW';


        WINDOW_NAME     REPEAT_INTERVAL                                              DURATION      ENABL
        --------------- ------------------------------------------------------------ ------------  --------
        FRIDAY_WINDOW   FREQ=WEEKLY;BYDAY=FRI;BYHOUR=23;BYMINUTE=30;BYSECOND=0       +000 04:00:0  TRUE

7、新增维护时间窗口
        -- 假定我们要处理的是修改周一的时间窗口
        -- 首先关闭周一的时间窗口
        BEGIN
           DBMS_AUTO_TASK_ADMIN.disable (
              client_name   => 'auto optimizer stats collection',
              operation     => NULL,
              window_name   => 'MONDAY_WINDOW');
        END;
        /

        --接下来创建一个窗口并设定时间调度间隔
        --如下，每周一5点执行，持续时间为1小时
        BEGIN
           DBMS_SCHEDULER.create_window (
              window_name       => 'STATS_WINDOW',
              resource_plan     => 'DEFAULT_MAINTENANCE_PLAN',
              repeat_interval   => 'freq=daily;byday=MON;byhour=5;byminute=0; bysecond=0',
              duration          => INTERVAL '1' HOUR,
              comments          => 'Test window for stats task');
        EXCEPTION
           WHEN OTHERS
           THEN
              IF SQLCODE = -27477
              THEN
                 NULL;
              ELSE
                 RAISE;
              END IF;
        END;

        BEGIN
           DBMS_SCHEDULER.set_attribute ('STATS_WINDOW', 'SYSTEM', TRUE);
           DBMS_SCHEDULER.set_attribute ('STATS_WINDOW',
                                         'FOLLOW_DEFAULT_TIMEZONE',
                                         TRUE);
        EXCEPTION
           WHEN OTHERS
           THEN
              IF SQLCODE = -27477
              THEN
                 NULL;
              ELSE
                 RAISE;
              END IF;
        END;
        /

        SQL> SELECT window_name, repeat_interval, enabled
          2  FROM   dba_scheduler_windows
          3  WHERE  window_name = 'STATS_WINDOW';

        WINDOW_NAME                    REPEAT_INTERVAL                                              ENABL
        ------------------------------ ------------------------------------------------------------ -----
        STATS_WINDOW                   freq=daily;byday=MON;byhour=5;byminute=0; bysecond=0         TRUE

        --接下来将窗口STATS_WINDOW添加到维护窗口组

        BEGIN
           DBMS_SCHEDULER.add_window_group_member ('MAINTENANCE_WINDOW_GROUP',
                                                   'STATS_WINDOW');
        END;
        /

        SQL> SELECT WINDOW_NAME,
          2         WINDOW_NEXT_TIME,
          3         WINDOW_ACTIVE,
          4         OPTIMIZER_STATS
          5  FROM   DBA_AUTOTASK_WINDOW_CLIENTS
          6  WHERE  WINDOW_NAME in ('STATS_WINDOW','MONDAY_WINDOW') 
          7  ORDER BY WINDOW_NEXT_TIME;

        WINDOW_NAME                    WINDOW_NEXT_TIME                       WINDO OPTIMIZE
        ------------------------------ -------------------------------------- ----- --------
        STATS_WINDOW                   27-MAR-17 05.00.00.000000 AM PRC       FALSE ENABLED   --允许
        MONDAY_WINDOW                  27-MAR-17 10.00.00.000000 PM PRC       FALSE DISABLED  --当前被disabled

三、手工执行统计信息的自动收集

SQL> create table scott.tb_objs as select * from dba_objects;

        SQL> select TABLE_NAME,NUM_ROWS,BLOCKS,LAST_ANALYZED from dba_tables where TABLE_NAME='TB_OBJS';

        TABLE_NAME                       NUM_ROWS     BLOCKS LAST_ANAL
        ------------------------------ ---------- ---------- ---------
        TB_OBJS

        --执行下面的这个存储过程
        SQL> EXEC DBMS_AUTO_TASK_IMMEDIATE.GATHER_OPTIMIZER_STATS;

        PL/SQL procedure successfully completed.

        --如下查询，scott表上的统计信息已更新
        SQL> select TABLE_NAME,NUM_ROWS,BLOCKS,LAST_ANALYZED from dba_tables where TABLE_NAME='TB_OBJS';

        TABLE_NAME                       NUM_ROWS     BLOCKS LAST_ANAL
        ------------------------------ ---------- ---------- ---------
        TB_OBJS                             75548       1103 25-MAR-17

四、参考链接