saa傻瓜優化祕籍：

1、創建基於cache的job

 
DECLARE
  l_taskname VARCHAR2(30) := 'test_sql_access_task';
  l_task_desc VARCHAR2(128) := 'Test SQL Access Task';
  l_wkld_name VARCHAR2(30) := 'test_work_load';
  l_saved_rows NUMBER := 0;
  l_failed_rows NUMBER := 0;
  l_num_found NUMBER;
BEGIN
  -- Create an SQLAccess Advisor task.
  DBMS_ADVISOR.create_task(
                           advisor_name => DBMS_ADVISOR.sqlaccess_advisor,
                           task_name => l_taskname,
                           task_desc => l_task_desc);
  -- Reset the task.
  DBMS_ADVISOR.reset_task(task_name => l_taskname);
  -- Create a workload.
  SELECT COUNT(*)
    INTO l_num_found
    FROM user_advisor_sqlw_sum
   WHERE workload_name = l_wkld_name;
  IF l_num_found = 0 THEN
  DBMS_ADVISOR.create_sqlwkld(workload_name => l_wkld_name);
  END IF;
  -- Link the workload to the task.
  SELECT count(*)
    INTO l_num_found
    FROM user_advisor_sqla_wk_map
   WHERE task_name = l_taskname
     AND workload_name = l_wkld_name;
  IF l_num_found = 0 THEN
  DBMS_ADVISOR.add_sqlwkld_ref(
                               task_name => l_taskname,
                               workload_name => l_wkld_name);
  END IF;
  -- Set workload parameters.
  DBMS_ADVISOR.set_sqlwkld_parameter(l_wkld_name,
                                     'ACTION_LIST',
                                     DBMS_ADVISOR.ADVISOR_UNUSED);
  DBMS_ADVISOR.set_sqlwkld_parameter(l_wkld_name,
                                     'MODULE_LIST',
                                     DBMS_ADVISOR.ADVISOR_UNUSED);
  DBMS_ADVISOR.set_sqlwkld_parameter(l_wkld_name,
                                     'SQL_LIMIT',
                                     DBMS_ADVISOR.ADVISOR_UNLIMITED);
  DBMS_ADVISOR.set_sqlwkld_parameter(l_wkld_name,
                                     'ORDER_LIST',
                                     'PRIORITY,OPTIMIZER_COST');
  DBMS_ADVISOR.set_sqlwkld_parameter(l_wkld_name,
                                     'USERNAME_LIST',
                                     DBMS_ADVISOR.ADVISOR_UNUSED);
  DBMS_ADVISOR.set_sqlwkld_parameter(l_wkld_name,
                                     'VALID_TABLE_LIST',
                                     DBMS_ADVISOR.ADVISOR_UNUSED);
                                     
 --                                    
                                     
  DBMS_ADVISOR.import_sqlwkld_sqlcache(l_wkld_name,
                                       'REPLACE',
                                       2,
                                       l_saved_rows,
                                       l_failed_rows);
  -- Set task parameters.
  DBMS_ADVISOR.set_task_parameter(l_taskname,
                                  '_MARK_IMPLEMENTATION',
                                  'FALSE');
  DBMS_ADVISOR.set_task_parameter(l_taskname,
                                  'EXECUTION_TYPE',
                                  'INDEX_ONLY');
  DBMS_ADVISOR.set_task_parameter(l_taskname, 'MODE', 'COMPREHENSIVE');
  DBMS_ADVISOR.set_task_parameter(l_taskname,
                                  'STORAGE_CHANGE',
                                  DBMS_ADVISOR.ADVISOR_UNLIMITED);
  DBMS_ADVISOR.set_task_parameter(l_taskname, 'DML_VOLATILITY', 'TRUE');
  DBMS_ADVISOR.set_task_parameter(l_taskname,
                                  'ORDER_LIST',
                                  'PRIORITY,OPTIMIZER_COST');
  DBMS_ADVISOR.set_task_parameter(l_taskname, 'WORKLOAD_SCOPE', 'PARTIAL');
  DBMS_ADVISOR.set_task_parameter(l_taskname,
                                  'DEF_INDEX_TABLESPACE',
                                  DBMS_ADVISOR.ADVISOR_UNUSED);
  DBMS_ADVISOR.set_task_parameter(l_taskname,
                                  'DEF_INDEX_OWNER',
                                  DBMS_ADVISOR.ADVISOR_UNUSED);
  DBMS_ADVISOR.set_task_parameter(l_taskname,
                                  'DEF_MVIEW_TABLESPACE',
                                  DBMS_ADVISOR.ADVISOR_UNUSED);
  DBMS_ADVISOR.set_task_parameter(l_taskname,
                                  'DEF_MVIEW_OWNER',
                                  DBMS_ADVISOR.ADVISOR_UNUSED);
  -- Execute the task.
  DBMS_ADVISOR.execute_task(task_name => l_taskname);
END;
/

2、查看saa建議

  SET LONG 100000
 SET PAGESIZE 50000
SELECT DBMS_ADVISOR.get_task_script('test_sql_access_task') AS script FROM  dual;

3、查看saa的建議的性能提高效果預估

 

 SELECT sql_id,
   precost 優化前cost,
 postcost 優化後cost,
   (precost / postcost) cost提升倍數，decode(PRIORITY, 1, '高', 2, '中', 3, '低') 重要性
   FROM dba_advisor_sqla_wk_stmts
WHERE
 task_name='test_sql_access_task';

4、反查sql語法

 
select SQL_TEXT,SQL_FULLTEXT,SQL_ID,LOADS,FIRST_LOAD_TIME,PLSQL_EXEC_TIME,JAVA_EXEC_TIME,ROWS_PROCESSED,COMMAND_TYPE,PARSING_USER_ID,PARSING_SCHEMA_ID,PARSING_SCHEMA_NAME,KEPT_VERSIONS,ADDRESS,SERVICE,MODULE,MODULE_HASH,ACTION,CPU_TIME,ELAPSED_TIME,OUTLINE_SID,CHILD_ADDRESS,SQLTYPE,REMOTE,OBJECT_STATUS,LITERAL_HASH_VALUE,LAST_LOAD_TIME,PROGRAM_ID,PROGRAM_LINE#,LAST_ACTIVE_TIME 
from  v$sql where sql_id in (
 
 SELECT sql_id
   FROM dba_advisor_sqla_wk_stmts
WHERE
 task_name='test_sql_access_task' and  (precost / postcost)>10 and postcost<>0)



 
select * from  dba_hist_sqltext  where sql_id in (
 
 SELECT sql_id
   FROM dba_advisor_sqla_wk_stmts
WHERE
 task_name='test_sql_access_task' and  (precost / postcost)>10 and postcost<>0)

select distinct substr(to_char(sql_text),1,20) from  dba_hist_sqltext  where sql_id in (
 
 SELECT sql_id
   FROM dba_advisor_sqla_wk_stmts
WHERE
 task_name='test_sql_access_task' and  (precost / postcost)>10 and postcost<>0)

 
 
select distinct to_char(sql_text) from  dba_hist_sqltext  where sql_id in (
 
 SELECT sql_id
   FROM dba_advisor_sqla_wk_stmts
WHERE
 task_name='test_sql_access_task' and  (precost / postcost)>10 and postcost<>0)

找那些提升明顯的sql進行優化