create table test0605 as select * from dba_objects;

select t1.owner,t1.object_name,t1.object_id from test0605 t1 where t1.object_id=3344;

select t1.SQL_ID,t1.HASH_VALUE,t1.SQL_TEXT,t1.SQL_FULLTEXT,to_char(t1.LAST_ACTIVE_TIME,'yyyy-mm-dd hh24:mi:ss') LAST_ACTIVE_TIME ,to_char(t1.LAST_LOAD_TIME,'yyyy-mm-dd hh24:mi:ss') LAST_LOAD_TIME from v$sqlarea t1 where t1.SQL_FULLTEXT like '%test0605 t1 where t1.object_id=3344%'
order by LAST_ACTIVE_TIME desc,LAST_LOAD_TIME desc;

/*select * from v$sql_plan t1 where t1.;

select * from v$sql_plan_statistics;

select * from v$sql_workarea;*/

select * from v$sql_plan_statistics_all t1 where t1.SQL_ID='f21sgfyqvkz9m';

select * from table(dbms_xplan.display_cursor('f21sgfyqvkz9m',0,'advanced'));

select * from table(dbms_xplan.display_awr('f21sgfyqvkz9m'));

--1008
关于一定时期内显著的执行计划变动、资源消耗变动 ,oracle提供了awrsqrpt.sql 、spresql.sql两个脚本

--1021
1030
包含执行计划的表中的字段

基本字段
字段                              描述
id                                每一个操作的标识符。如果数字前面带有星号,意味着该行有谓词信息
operation                         该行的操作,也叫 row source
name                              操作的对象

查询优化器评估类
rows(e-rows)                              评估中操作返回的记录总数
bytes(e-bytes)                            评估中操作返回的字节数
tempspc                                   评估中操作使用的临时空间大小
cost(%cpu)                                评估中操作的开销。括号中是开销的百分比。注意该值是通过执行计划计算过来的。即:父操作的开销包含子操作的开销
time                                      评估中执行操作需要的时间

分区类
pstart                                    访问的第一个分区。如果解析时不知道是哪个分区就设为key、key(i) 、key(mc)、 key(or)、 key(sq)
pstop                                     访问的最后一个分区。如果解析时不知道是哪个分区就设为key、key(i) 、key(mc)、 key(or)、 key(sq)

运行时统计
starts                                    指定操作执行的次数
a-rows                                    指定操作返回的真实记录数
a-time                                    指定操作执行的真实时间

io统计类
buffers                                   操作期间进行的逻辑读数量
reads                                     操作期间进行的物理读数量
writes                                    操作期间进行的物理写数量

内存使用统计类
0mem                                      最优执行所需内存的评估值
1mem                                      一次性通过(one-pass)执行所需内存的评估值
used-mem                                  最后一次操作时使用的内存量
user-tmp                                  最后一次操作时使用的临时空间大小

--1439 display函数
/*
format参数可用的基本值
basic                                   仅显示最少的信息。基本上之报错操作和操作的对象
typical                                 显示大部分相关内容,基本上包含除了别名,提纲和字段投影外的所有信息                                        
serial                                  和typical类似,只是没有并行的相关信息
all                                     显示除了提纲外的所有信息
advanced                                显示所有信息
alias                                   空值包含查询块名和对象别名那一部分的显示
bytes                                   控制执行计划表中字段bytes的显示
cost                                    控制执行计划表中字段cost的显示
note                                    控制包含注意信息note那一部分的显示
outline                                 控制包含提纲outline那一部分的显示
parallel                                空值并行处理信息的显示,尤其是,执行计划表中字段TQ、IN-OUT、PQ distrib的显示
partition                               控制分区信息的显示,尤其是pstart和pstop的显示
peek_binds                              控制包含被窥测的绑定变量那一部分的显示。
predicate                               控制包含谓词filter和access那一部分的显示
projection                              控制包含字段投影信息那一部分的显示
remote                                  控制远程执行的sql语句的显示
rows                                    控制执行计划表中字段rows的显示
*/

--1055

--case 1
SQL> CREATE TABLE t AS SELECT * FROM o;
SQL> execute dbms_stats.gather_table_stats(user, 't')
SQL> EXPLAIN PLAN FOR CREATE TABLE t AS SELECT * FROM o;
SQL>
SQL> SELECT * FROM table(dbms_xplan.display);

PLAN_TABLE_OUTPUT                                                                                                       
------------------------------------------------------------------------------------------------------------------------
Plan hash value: 1827057699                                                                                             
                                                                                                                        
-------------------------------------------------------------------------------                                         
| Id  | Operation              | Name | Rows  | Bytes | Cost (%CPU)| Time     |                                         
-------------------------------------------------------------------------------                                         
|   0 | CREATE TABLE STATEMENT |      |  1000 | 84000 |     5   (0)| 00:00:01 |                                         
|   1 |  LOAD AS SELECT        | T    |       |       |            |          |                                         
|   2 |   TABLE ACCESS FULL    | O    |  1000 | 84000 |     3   (0)| 00:00:01 |                                         
-------------------------------------------------------------------------------

--case2
SQL> CREATE INDEX i ON t (object_id);
SQL>
SQL> EXPLAIN PLAN FOR ALTER INDEX i REBUILD;
SQL>
SQL> SELECT * FROM table(dbms_xplan.display);

PLAN_TABLE_OUTPUT                                                                                                       
------------------------------------------------------------------------------------------------------------------------
Plan hash value: 1634214326                                                                                             
                                                                                                                        
-------------------------------------------------------------------------------                                         
| Id  | Operation              | Name | Rows  | Bytes | Cost (%CPU)| Time     |                                         
-------------------------------------------------------------------------------                                         
|   0 | ALTER INDEX STATEMENT  |      |  1000 |  4000 |     2   (0)| 00:00:01 |                                         
|   1 |  INDEX BUILD NON UNIQUE| I    |       |       |            |          |                                         
|   2 |   SORT CREATE INDEX    |      |  1000 |  4000 |            |          |                                         
|   3 |    INDEX FAST FULL SCAN| I    |  1000 |  4000 |     2   (0)| 00:00:01 |                                         
-------------------------------------------------------------------------------

--case3
SQL> EXPLAIN PLAN FOR SELECT * FROM t;
SQL>
SQL> SELECT * FROM table(dbms_xplan.display);

PLAN_TABLE_OUTPUT                                                                                                       
------------------------------------------------------------------------------------------------------------------------
Plan hash value: 1601196873                                                                                             
                                                                                                                        
--------------------------------------------------------------------------                                              
| Id  | Operation         | Name | Rows  | Bytes | Cost (%CPU)| Time     |                                              
--------------------------------------------------------------------------                                              
|   0 | SELECT STATEMENT  |      |  1000 | 84000 |     3   (0)| 00:00:01 |                                              
|   1 |  TABLE ACCESS FULL| T    |  1000 | 84000 |     3   (0)| 00:00:01 |                                              
--------------------------------------------------------------------------

--case4
SQL> EXPLAIN PLAN FOR INSERT INTO t SELECT * FROM o WHERE rownum = 1;
SQL>
SQL> SELECT * FROM table(dbms_xplan.display);

PLAN_TABLE_OUTPUT                                                                                                       
------------------------------------------------------------------------------------------------------------------------
Plan hash value: 1110922135                                                                                             
                                                                                                                        
---------------------------------------------------------------------------------                                       
| Id  | Operation                | Name | Rows  | Bytes | Cost (%CPU)| Time     |                                       
---------------------------------------------------------------------------------                                       
|   0 | INSERT STATEMENT         |      |     1 |    84 |     3   (0)| 00:00:01 |                                       
|   1 |  LOAD TABLE CONVENTIONAL | T    |       |       |            |          |                                       
|*  2 |   COUNT STOPKEY          |      |       |       |            |          |                                       
|   3 |    TABLE ACCESS FULL     | O    |  1000 | 84000 |     3   (0)| 00:00:01 |                                       
---------------------------------------------------------------------------------                                       
                                                                                                                        
Predicate Information (identified by operation id):                                                                     
---------------------------------------------------                                                                     
                                                                                                                        
   2 - filter(ROWNUM=1)                                                              
   
--case5
SQL> EXPLAIN PLAN FOR UPDATE t SET subobject_name = object_name;
SQL>
SQL> SELECT * FROM table(dbms_xplan.display);

PLAN_TABLE_OUTPUT                                                                                                       
------------------------------------------------------------------------------------------------------------------------
Plan hash value: 931696821                                                                                              
                                                                                                                        
---------------------------------------------------------------------------                                             
| Id  | Operation          | Name | Rows  | Bytes | Cost (%CPU)| Time     |                                             
---------------------------------------------------------------------------                                             
|   0 | UPDATE STATEMENT   |      |  1000 | 33000 |     3   (0)| 00:00:01 |                                             
|   1 |  UPDATE            | T    |       |       |            |          |                                             
|   2 |   TABLE ACCESS FULL| T    |  1000 | 33000 |     3   (0)| 00:00:01 |                                             
---------------------------------------------------------------------------

--case6
SQL> EXPLAIN PLAN FOR MERGE INTO t
  2                USING (SELECT * FROM o) o
  3                ON (t.object_id = o.object_id)
  4                WHEN MATCHED THEN UPDATE SET t.subobject_name = o.subobject_name
  5                WHEN NOT MATCHED THEN INSERT (owner, object_name, object_id, created, last_ddl_time)
  6                          VALUES (o.owner, o.object_name, o.object_id, o.created, o.last_ddl_time);
SQL>
SQL> SELECT * FROM table(dbms_xplan.display);

PLAN_TABLE_OUTPUT                                                                                                       
------------------------------------------------------------------------------------------------------------------------
Plan hash value: 4087175684                                                                                             
                                                                                                                        
-----------------------------------------------------------------------------                                           
| Id  | Operation            | Name | Rows  | Bytes | Cost (%CPU)| Time     |                                           
-----------------------------------------------------------------------------                                           
|   0 | MERGE STATEMENT      |      |  1000 |   162K|     7  (15)| 00:00:01 |                                           
|   1 |  MERGE               | T    |       |       |            |          |                                           
|   2 |   VIEW               |      |       |       |            |          |                                           
|*  3 |    HASH JOIN OUTER   |      |  1000 |   164K|     7  (15)| 00:00:01 |                                           
|   4 |     TABLE ACCESS FULL| O    |  1000 | 84000 |     3   (0)| 00:00:01 |                                           
|   5 |     TABLE ACCESS FULL| T    |  1000 | 84000 |     3   (0)| 00:00:01 |                                           
-----------------------------------------------------------------------------                                           
                                                                                                                        
Predicate Information (identified by operation id):                                                                     
---------------------------------------------------                                                                     
                                                                                                                        
   3 - access("T"."OBJECT_ID"(+)="O"."OBJECT_ID")                   
   
--case7
SQL> EXPLAIN PLAN FOR DELETE FROM t;
SQL>
SQL> SELECT * FROM table(dbms_xplan.display);

PLAN_TABLE_OUTPUT                                                                                                       
------------------------------------------------------------------------------------------------------------------------
Plan hash value: 3335594643                                                                                             
                                                                                                                        
---------------------------------------------------------------------------                                             
| Id  | Operation          | Name | Rows  | Bytes | Cost (%CPU)| Time     |                                             
---------------------------------------------------------------------------                                             
|   0 | DELETE STATEMENT   |      |  1000 |  4000 |     3   (0)| 00:00:01 |                                             
|   1 |  DELETE            | T    |       |       |            |          |                                             
|   2 |   TABLE ACCESS FULL| T    |  1000 |  4000 |     3   (0)| 00:00:01 |                                             
---------------------------------------------------------------------------

--1519
dbms_xplan.display_cursor

/*
format可用的修饰符
allstats*     是iostats  memstats的快捷方式
iostat*       控制I/0统计的显示
last*         默认,显示所有执行计划过的统计。如果指定此值,只显示最后一次执行的统计信息
memstats*     控制pga相关统计的显示
runstats_last 和iostats last 相同,适用于 oracle10g r1
runstats_tot  和iostats相同。适用于 oracle10g r1

以上附带*表示从oracle10g r2 起可以使用
*/

case1
SQL> UPDATE t
  2  SET val = (SELECT /*+ index(t) */ max(val) FROM t WHERE id BETWEEN 6 AND 19),
  3      pad = (SELECT pad FROM t WHERE id = 6)
  4  WHERE id IN (SELECT id FROM t WHERE id BETWEEN 6 AND 19);
SQL>
SQL> SELECT * FROM table(dbms_xplan.display_cursor(NULL,NULL,'basic'));

PLAN_TABLE_OUTPUT
---------------------------------------------------------------------------------------------------------------------------------------------
EXPLAINED SQL STATEMENT:
------------------------
UPDATE t SET val = (SELECT /*+ index(t) */ max(val) FROM t WHERE id
BETWEEN 6 AND 19),     pad = (SELECT pad FROM t WHERE id = 6) WHERE id
IN (SELECT id FROM t WHERE id BETWEEN 6 AND 19)

Plan hash value: 2674170182

----------------------------------------------
| Id  | Operation                     | Name |
----------------------------------------------
|   0 | UPDATE STATEMENT              |      |
|   1 |  UPDATE                       | T    |
|   2 |   NESTED LOOPS                |      |
|   3 |    TABLE ACCESS FULL          | T    |
|   4 |    INDEX UNIQUE SCAN          | T_PK |
|   5 |   SORT AGGREGATE              |      |
|   6 |    TABLE ACCESS BY INDEX ROWID| T    |
|   7 |     INDEX FULL SCAN           | I    |
|   8 |   TABLE ACCESS BY INDEX ROWID | T    |
|   9 |    INDEX UNIQUE SCAN          | T_PK |
----------------------------------------------

--case2
SQL> SELECT deptno, count(*)
  2  FROM emp
  3  WHERE job = 'CLERK' AND sal < 1200
  4  GROUP BY deptno;
SQL>
SQL> SELECT * FROM table(dbms_xplan.display_cursor(null,null,'iostats last'));

PLAN_TABLE_OUTPUT
------------------------------------------------------------------------------------------------------------
SQL_ID  5k3rhmx9hprh7, child number 0
-------------------------------------
SELECT deptno, count(*) FROM emp WHERE job = 'CLERK' AND sal < 1200
GROUP BY deptno

Plan hash value: 4067220884

--------------------------------------------
| Id  | Operation          | Name | E-Rows |
--------------------------------------------
|   0 | SELECT STATEMENT   |      |        |
|   1 |  HASH GROUP BY     |      |      1 |
|*  2 |   TABLE ACCESS FULL| EMP  |      1 |
--------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

2 - filter(("JOB"='CLERK' AND "SAL"<1200))

Note
-----
   - Warning: basic plan statistics not available. These are only collected when:
       * hint 'gather_plan_statistics' is used for the statement or
       * parameter 'statistics_level' is set to 'ALL', at session or system level

--case3
SQL> SELECT *
  2  FROM emp
  3  WHERE rownum <= 10;
SQL>
SQL> SELECT * FROM table(dbms_xplan.display_cursor(null,null,'iostats last'));

PLAN_TABLE_OUTPUT
-----------------------------------------------------------------------------------------------------------------------
SQL_ID  ajp501ttxv1vn, child number 0
-------------------------------------
SELECT * FROM emp WHERE rownum <= 10

Plan hash value: 1973284518

--------------------------------------------
| Id  | Operation          | Name | E-Rows |
--------------------------------------------
|   0 | SELECT STATEMENT   |      |        |
|*  1 |  COUNT STOPKEY     |      |        |
|   2 |   TABLE ACCESS FULL| EMP  |      1 |
--------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

1 - filter(ROWNUM<=10)

Note
-----
   - Warning: basic plan statistics not available. These are only collected when:
       * hint 'gather_plan_statistics' is used for the statement or
       * parameter 'statistics_level' is set to 'ALL', at session or system level

--case4
SQL> SELECT *
  2  FROM (
  3    SELECT *
  4    FROM emp
  5    ORDER BY sal DESC
  6  )
  7  WHERE rownum <= 10;
SQL>
SQL> SELECT * FROM table(dbms_xplan.display_cursor(null,null,'iostats last'));

PLAN_TABLE_OUTPUT
-----------------------------------------------------------------------------------------------------------------
SQL_ID  7jpchs5c5bstu, child number 0
-------------------------------------
SELECT * FROM (   SELECT *   FROM emp   ORDER BY sal DESC ) WHERE
rownum <= 10

Plan hash value: 1744961472

-------------------------------------------------
| Id  | Operation               | Name | E-Rows |
-------------------------------------------------
|   0 | SELECT STATEMENT        |      |        |
|*  1 |  COUNT STOPKEY          |      |        |
|   2 |   VIEW                  |      |      1 |
|*  3 |    SORT ORDER BY STOPKEY|      |      1 |
|   4 |     TABLE ACCESS FULL   | EMP  |      1 |
-------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

1 - filter(ROWNUM<=10)
   3 - filter(ROWNUM<=10)

Note
-----
   - Warning: basic plan statistics not available. These are only collected when:
       * hint 'gather_plan_statistics' is used for the statement or
       * parameter 'statistics_level' is set to 'ALL', at session or system level
       
--case5
SQL> SELECT *
  2  FROM emp
  3  WHERE job = 'CLERK'
  4  AND 1=2;
SQL>
SQL> SELECT * FROM table(dbms_xplan.display_cursor(null,null,'iostats last'));

PLAN_TABLE_OUTPUT
------------------------------------------------------------------------------------------------------
SQL_ID  7vajq952vnrbk, child number 0
-------------------------------------
SELECT * FROM emp WHERE job = 'CLERK' AND 1=2

Plan hash value: 3896240783

--------------------------------------------
| Id  | Operation          | Name | E-Rows |
--------------------------------------------
|   0 | SELECT STATEMENT   |      |        |
|*  1 |  FILTER            |      |        |
|*  2 |   TABLE ACCESS FULL| EMP  |      1 |
--------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

1 - filter(NULL IS NOT NULL)
   2 - filter("JOB"='CLERK')

Note
-----
   - Warning: basic plan statistics not available. These are only collected when:
       * hint 'gather_plan_statistics' is used for the statement or
       * parameter 'statistics_level' is set to 'ALL', at session or system level
       
--case 6
SQL> SELECT ename FROM emp
  2  UNION ALL
  3  SELECT dname FROM dept
  4  UNION ALL
  5  SELECT '%' FROM dual;

ENAME
----------
ACCOUNTING
RESEARCH
SALES
OPERATIONS
%
SQL>
SQL> SELECT * FROM table(dbms_xplan.display_cursor(null,null,'iostats last'));

PLAN_TABLE_OUTPUT
---------------------------------------------------------------------------------------------
SQL_ID  781xq971h0y2p, child number 0
-------------------------------------
SELECT ename FROM emp UNION ALL SELECT dname FROM dept UNION ALL SELECT
'%' FROM dual

Plan hash value: 4181933179

--------------------------------------------
| Id  | Operation          | Name | E-Rows |
--------------------------------------------
|   0 | SELECT STATEMENT   |      |        |
|   1 |  UNION-ALL         |      |        |
|   2 |   TABLE ACCESS FULL| EMP  |      1 |
|   3 |   TABLE ACCESS FULL| DEPT |      4 |
|   4 |   FAST DUAL        |      |      1 |
--------------------------------------------

Note
-----
   - Warning: basic plan statistics not available. These are only collected when:
       * hint 'gather_plan_statistics' is used for the statement or
       * parameter 'statistics_level' is set to 'ALL', at session or system level
       
--case7
SQL> SELECT /*+ ordered use_nl(dept) index(dept) */ *
  2  FROM emp, dept
  3  WHERE emp.deptno = dept.deptno
  4  AND emp.comm IS NULL
  5  AND dept.dname != 'SALES';
SQL>
SQL> SELECT * FROM table(dbms_xplan.display_cursor(null,null,'iostats last'));

PLAN_TABLE_OUTPUT
---------------------------------------------------------------------------------------------------
SQL_ID  3ux4g340c933p, child number 0
-------------------------------------
SELECT /*+ ordered use_nl(dept) index(dept) */ * FROM emp, dept WHERE
emp.deptno = dept.deptno AND emp.comm IS NULL AND dept.dname != 'SALES'

Plan hash value: 2694310824

---------------------------------------------------------
| Id  | Operation                    | Name    | E-Rows |
---------------------------------------------------------
|   0 | SELECT STATEMENT             |         |        |
|   1 |  NESTED LOOPS                |         |        |
|   2 |   NESTED LOOPS               |         |      1 |
|*  3 |    TABLE ACCESS FULL         | EMP     |      1 |
|*  4 |    INDEX UNIQUE SCAN         | DEPT_PK |      1 |
|*  5 |   TABLE ACCESS BY INDEX ROWID| DEPT    |      1 |
---------------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

3 - filter("EMP"."COMM" IS NULL)
   4 - access("EMP"."DEPTNO"="DEPT"."DEPTNO")
   5 - filter("DEPT"."DNAME"<>'SALES')

Note
-----
   - Warning: basic plan statistics not available. These are only collected when:
       * hint 'gather_plan_statistics' is used for the statement or
       * parameter 'statistics_level' is set to 'ALL', at session or system level
       
--case 8
SQL> SELECT *
  2  FROM emp
  3  WHERE NOT EXISTS (SELECT /*+ no_unnest */ 0
  4                    FROM dept
  5                    WHERE dept.dname = 'SALES' AND dept.deptno = emp.deptno)
  6  AND NOT EXISTS (SELECT /*+ no_unnest */ 0
  7                  FROM bonus
  8                  WHERE bonus.ename = emp.ename);
                FROM bonus
                     *
第 7 行出现错误:
ORA-00942: ???????

SQL>
SQL> SELECT * FROM table(dbms_xplan.display_cursor(null,null,'iostats last'));

PLAN_TABLE_OUTPUT
-------------------------------------------------------------------------------------------------------
SQL_ID  2tty67sw0nz6c, child number 1
-------------------------------------
SELECT * FROM table(dbms_xplan.display_cursor(null,null,'iostats last'))

Plan hash value: 3713220770

---------------------------------------------------------------------
| Id  | Operation                         | Name           | E-Rows |
---------------------------------------------------------------------
|   0 | SELECT STATEMENT                  |                |        |
|   1 |  COLLECTION ITERATOR PICKLER FETCH| DISPLAY_CURSOR |     52 |
---------------------------------------------------------------------

Note
-----
   - cardinality feedback used for this statement
   - Warning: basic plan statistics not available. These are only collected when:
       * hint 'gather_plan_statistics' is used for the statement or
       * parameter 'statistics_level' is set to 'ALL', at session or system level

--1555
SQL> CREATE TABLE t
  2  PARTITION BY HASH (id)
  3  PARTITIONS 2
  4  AS
  5  SELECT rownum AS id, rownum AS n, lpad('*',1000,'*') AS pad
  6  FROM dual
  7  CONNECT BY level <= 1000;
SQL>
SQL> PAUSE

SQL>
SQL> REM Display information about partitioning (columns Pstart and Pstop) and
SQL> REM temporary space (column TempSpc)
SQL>
SQL> SELECT /*+ gather_plan_statistics */ count(pad)
  2  FROM (SELECT /* parallel(t,2) */ rownum AS rn, pad
  3        FROM t
  4        ORDER BY n)
  5  WHERE rn = 1;

COUNT(PAD)
----------
         1
SQL> /

COUNT(PAD)
----------
         1
SQL> /

COUNT(PAD)
----------
         1
SQL> /

COUNT(PAD)
----------
         1
SQL>
SQL> SELECT * FROM table(dbms_xplan.display_cursor);

PLAN_TABLE_OUTPUT
-------------------------------------------------------------------------------------------------------------------------
SQL_ID  6rwckvk4d8xjb, child number 0
-------------------------------------
SELECT /*+ gather_plan_statistics */ count(pad) FROM (SELECT /*
parallel(t,2) */ rownum AS rn, pad       FROM t       ORDER BY n) WHERE
rn = 1

Plan hash value: 2056542717

-------------------------------------------------------------------------------------------------------
| Id  | Operation              | Name | Rows  | Bytes |TempSpc| Cost (%CPU)| Time     | Pstart| Pstop |
-------------------------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT       |      |       |       |       |   171 (100)|          |       |       |
|   1 |  SORT AGGREGATE        |      |     1 |   515 |       |            |          |       |       |
|*  2 |   VIEW                 |      |  1177 |   591K|       |   171   (2)| 00:00:02 |       |       |
|   3 |    SORT ORDER BY       |      |  1177 |   591K|   640K|   171   (2)| 00:00:02 |       |       |
|   4 |     COUNT              |      |       |       |       |            |          |       |       |
|   5 |      PARTITION HASH ALL|      |  1177 |   591K|       |    19   (0)| 00:00:01 |     1 |     2 |
|   6 |       TABLE ACCESS FULL| T    |  1177 |   591K|       |    19   (0)| 00:00:01 |     1 |     2 |
-------------------------------------------------------------------------------------------------------

--1744
SQL> alter session set statistics_level=all;

Session altered.

执行这步之后,执行计划中才会显示  starts

select /*+ gather_plan_statistics */ * from data_skew;

select * from table(dbms_xplan.display_cursor(null,null,'advanced'));

select * from data_skew where rownum < 101;

---  4dy2ffhhyud3c    569193580    0    select * from data_skew where rownum <100     1    2017/6/6 14:21:36    2017/6/6 14:21:35

SELECT * FROM table(dbms_xplan.display_cursor('6rwckvk4d8xjb',0,'iostats last'));

--case 2 advanced
SELECT * FROM table(dbms_xplan.display_cursor('6rwckvk4d8xjb',0,'advanced'));

--case 3 typical
SELECT * FROM table(dbms_xplan.display_cursor('6rwckvk4d8xjb',0,'typical'));

--case 4 all
SELECT * FROM table(dbms_xplan.display_cursor('6rwckvk4d8xjb',0,'all'));

--case 5 memstats last
SELECT * FROM table(dbms_xplan.display_cursor('6rwckvk4d8xjb',0,'memstats last'));

SELECT * FROM table(dbms_xplan.display_cursor('6rwckvk4d8xjb',0,'iostats last'));

SELECT /*+ gather_plan_statistics */ count(pad)
FROM (SELECT /* parallel(t,2) */ rownum AS rn, pad
      FROM t
      ORDER BY n)
WHERE rn = 1;

grant execute on dbms_hpof to owner

dbms_profiler.

alter procedure sys.dbms_profiler.perfect_triangles compile debug;

grant all on dbms_profiler to public;

dbms_output.put_line

select t1.object_name,t1.object_id,t1.object_type,t1.owner from dba_objects t1 where t1.object_name='PERFECT_TRIANGLES';

SELECT s.line,
       round(ratio_to_report(p.total_time) OVER ()*100,1) AS time,
       total_occur,
       s.text
FROM all_source s,
     (SELECT u.unit_owner, u.unit_name, u.unit_type,
             d.line#, d.total_time, d.total_occur
      FROM plsql_profiler_units u, plsql_profiler_data d
      WHERE u.runid = &runid
      AND d.runid = u.runid
      AND d.unit_number = u.unit_number) p
WHERE s.owner = p.unit_owner (+)
AND s.name = p.unit_name (+)
AND s.type = p.unit_type (+)
AND s.line = p.line# (+)
AND s.owner = user
AND s.name = 'SLEEP'
ORDER BY s.line;

dbms_sql.

explain plan for select * from data_skew where rownum <2000;

exec dbms_stats.gather_table_stats(user,'DATA_SKEW');

select sys_context('userenv','sid') from dual;

select * from v$sql_plan_statistics ;

select /*+ gather_plan_statistics*/ * from t where n2=19;

select sps.LAST_OUTPUT_ROWS,
       sps.LAST_CR_BUFFER_GETS,
       sps.LAST_CU_BUFFER_GETS
  from v$session s, v$sql_plan_statistics sps
 where s.prev_sql_id = sps.sql_id
   and s.PREV_CHILD_NUMBER = sps.CHILD_NUMBER
   and s.sid = sys_context('userenv', 'sid')
   and sps.OPERATION_ID = 1;

dbms_stats.ObjectTab

select * from test0605;

alter table test0605 add (tmp_obj as (substr(object_name,1,3)));

SELECT partition_name, partition_position, num_rows
FROM user_tab_partitions
WHERE table_name = 'T'
ORDER BY partition_position;

select p.partition_position,p.partition_name,s.subpartition_position,s.subpartition_name
from user_tab_partitions p, user_tab_subpartitions s
where p.table_name='T' and s.table_name=p.table_name and
s.partition_name=p.partition_name
order by p.partition_position,s.subpartition_position;

select * from test0605;

exec dbms_stats.gather_table_stats(user,'TEST0605');

exec dbms_stats.gather_index_stats(user,'IDX_OBJECT_ID');

select /*+ index(test0605 IDX_OBJECT_ID) */ object_name from test0605 where object_id =3389;

explain plan for select /*+ index_ffs(test0605 IDX_OBJECT_ID) */ object_name from test0605 where object_id is not null;

select extract(hg from sql_id) from v$sql_cs_statistics;

select owner,object_id,extract('SYS' from O) from test;

select * /*,extract(YEAR FROM CREATED)*/ from test;

select * from dba_enabled_traces;

select * from v$diag_info where name='';

select * from tvd$xtat ;

select t1.pname,t1.pval1,t1.pval2 from sys.aux_stats$ t1
where t1.sname='SYSSTATS_MAIN';

select sum(t1.SINGLEBLKRDS) as count,sum(t1.SINGLEBLKRDTIM) time_ms  from v$filestat t1;

create table t as
select rownum as id,
round(dbms_random.normal*1000) as val1,
100+round(ln(rownum/3.25+2 )) as val2,
100+round(ln(rownum/3.25+2 )) as val3,
dbms_random.string('p',250) as pad
from all_objects
where rownum<=1000
order by dbms_random.value;

update t set val1=null where val1<0;

alter table t add constraints  t_pk primary key(id);

create index t_val1_i on t(val1);

create index t_val2_i on t(val2);

begin
  dbms_stats.gather_table_stats(
 ownname=>user,
 tabname=>'T',
 estimate_percent=>100,
 method_opt =>'for all columns size skewonly',
  cascade=>true);
  end;

select t1.NUM_ROWS,t1.BLOCKS,t1.EMPTY_BLOCKS,t1.AVG_SPACE,t1.CHAIN_CNT,t1.AVG_ROW_LEN
from user_tab_statistics t1
where t1.TABLE_NAME='T';

NUM_ROWS     BLOCKS EMPTY_BLOCKS  AVG_SPACE  CHAIN_CNT AVG_ROW_LEN
---------- ---------- ------------ ---------- ---------- -----------
      1000         44            0          0          0         266

/*
NUM_ROWS 表中数据的行数
BLOCKS  高水位线以下的数据块个数
EMPTY_BLOCKS 高水位线以上的数据块个数
AVG_SPACE 表中数据块的平均空闲空间(单位:字节)
CHAIN_CNT  涉及行迁移、行链接的总行数
AVG_ROW_LEN 表中平均每个记录的长度(单位:字节)
*/

select t1.column_name name,t1.num_distinct "#dst",t1.low_value,t1.high_value,
t1.density dens,t1.num_nulls "#null",t1.avg_col_len avglen,t1.HISTOGRAM,t1.num_buckets "#bkt"    
from user_tab_col_statistics t1
where t1.table_name='T';

NAME                                 #dst LOW_VALUE                                                        HIGH_VALUE                                                             DENS      #null     AVGLEN HISTOGRAM             #bkt
------------------------------ ---------- ---------------------------------------------------------------- ---------------------------------------------------------------- ---------- ---------- ---------- --------------- ----------
ID                                   1000 C102                                                             C20B                                                                   .001          0          4 NONE                     1
VAL1                                  457 C105                                                             C22160                                                           .002353264        481          3 HEIGHT BALANCED        254
VAL2                                    6 C20202                                                           C20207                                                                .0005          0          4 FREQUENCY                6
VAL3                                    6 C20202                                                           C20207                                                                .0005          0          4 FREQUENCY                6
PAD                                  1000 203F2C5D523371586E695D456775533C565A522A4F3128234F43502F77353026 7E7E7438735D7A464E77205B7B79454D517E384069784521344735457E2F2120       .001          0        251 HEIGHT BALANCED        254

select utl_raw.cast_to_number(low_value) as low_value,
utl_raw.cast_to_number(high_value) as high_value
from user_tab_col_statistics
where table_name='T'
and column_name='VAL1';

/*
LOW_VALUE HIGH_VALUE
---------- ----------
         4       3295
*/

begin
  dbms_stats.gather_index_stats(ownname =>user, indname =>'T_VAL1_I',estimate_percent=>100);
  end;

select t1.INDEX_NAME,t1.blevel,t1.LEAF_BLOCKS,t1.DISTINCT_KEYS,
t1.NUM_ROWS,t1.CLUSTERING_FACTOR,t1.AVG_LEAF_BLOCKS_PER_KEY,t1.AVG_DATA_BLOCKS_PER_KEY
from user_ind_statistics t1
where t1.TABLE_NAME='T';

/*
INDEX_NAME                         BLEVEL LEAF_BLOCKS DISTINCT_KEYS   NUM_ROWS CLUSTERING_FACTOR AVG_LEAF_BLOCKS_PER_KEY AVG_DATA_BLOCKS_PER_KEY
------------------------------ ---------- ----------- ------------- ---------- ----------------- ----------------------- -----------------------
T_PK                                    1           2          1000       1000               972                       1                       1
T_VAL1_I                                1           2           457        519               508                       1                       1
T_VAL2_I                                1           3             6       1000               174                       1                      29

BLEVEL 访问叶子快而需要读取的分支块的数量,包括根块
LEAF_BLOCKS 索引中的叶子块数量
DISTINCT_KEYS 索引中唯一键值总数
NUM_ROWS 索引中的键值数,对于主键来说 等同于 DISTINCT_KEYS
CLUSTERING_FACTOR 表明有多少临近的索引条目知道不同的数据块。
如果表中数据和索引的排序是相似的,那么 聚簇因子就小。最小值是表中非空数据的数据块总数
如果表中数据和索引的排序迥异,聚簇因子就非常大。最大值是索引中的键值数

*/

select i.index_name,i.clustering_factor,clustering_factor(user,i.table_name,ic.COLUMN_NAME) as my_clstf
from user_indexes i,user_ind_columns ic
where i.table_name='T' and i.index_name=ic.INDEX_NAME;

select * from v$fixed_table;

select * from user_tab_pending_stats;

20170531
0907
select dbms_stats.get_stats_history_retention() from dual;

select extract(hg from sql_id) from v$sql_cs_statistics;

select owner,object_id,extract('SYS' from O) from test;

select * /*,extract(YEAR FROM CREATED)*/ from test;

select * from dba_enabled_traces;

select * from v$diag_info where name='';

select * from tvd$xtat ;

select t1.pname,t1.pval1,t1.pval2 from sys.aux_stats$ t1
where t1.sname='SYSSTATS_MAIN';

select sum(t1.SINGLEBLKRDS) as count,sum(t1.SINGLEBLKRDTIM) time_ms  from v$filestat t1;

create table t as
select rownum as id,
round(dbms_random.normal*1000) as val1,
100+round(ln(rownum/3.25+2 )) as val2,
100+round(ln(rownum/3.25+2 )) as val3,
dbms_random.string('p',250) as pad
from all_objects
where rownum<=1000
order by dbms_random.value;

update t set val1=null where val1<0;

alter table t add constraints  t_pk primary key(id);

create index t_val1_i on t(val1);

create index t_val2_i on t(val2);

begin
  dbms_stats.gather_table_stats(
 ownname=>user,
 tabname=>'T',
 estimate_percent=>100,
 method_opt =>'for all columns size skewonly',
  cascade=>true);
  end;

select t1.NUM_ROWS,t1.BLOCKS,t1.EMPTY_BLOCKS,t1.AVG_SPACE,t1.CHAIN_CNT,t1.AVG_ROW_LEN
from user_tab_statistics t1
where t1.TABLE_NAME='T';

NUM_ROWS     BLOCKS EMPTY_BLOCKS  AVG_SPACE  CHAIN_CNT AVG_ROW_LEN
---------- ---------- ------------ ---------- ---------- -----------
      1000         44            0          0          0         266

/*
NUM_ROWS 表中数据的行数
BLOCKS  高水位线以下的数据块个数
EMPTY_BLOCKS 高水位线以上的数据块个数
AVG_SPACE 表中数据块的平均空闲空间(单位:字节)
CHAIN_CNT  涉及行迁移、行链接的总行数
AVG_ROW_LEN 表中平均每个记录的长度(单位:字节)
*/

select t1.column_name name,t1.num_distinct "#dst",t1.low_value,t1.high_value,
t1.density dens,t1.num_nulls "#null",t1.avg_col_len avglen,t1.HISTOGRAM,t1.num_buckets "#bkt"    
from user_tab_col_statistics t1
where t1.table_name='T';

NAME                                 #dst LOW_VALUE                                                        HIGH_VALUE                                                             DENS      #null     AVGLEN HISTOGRAM             #bkt
------------------------------ ---------- ---------------------------------------------------------------- ---------------------------------------------------------------- ---------- ---------- ---------- --------------- ----------
ID                                   1000 C102                                                             C20B                                                                   .001          0          4 NONE                     1
VAL1                                  457 C105                                                             C22160                                                           .002353264        481          3 HEIGHT BALANCED        254
VAL2                                    6 C20202                                                           C20207                                                                .0005          0          4 FREQUENCY                6
VAL3                                    6 C20202                                                           C20207                                                                .0005          0          4 FREQUENCY                6
PAD                                  1000 203F2C5D523371586E695D456775533C565A522A4F3128234F43502F77353026 7E7E7438735D7A464E77205B7B79454D517E384069784521344735457E2F2120       .001          0        251 HEIGHT BALANCED        254

select utl_raw.cast_to_number(low_value) as low_value,
utl_raw.cast_to_number(high_value) as high_value
from user_tab_col_statistics
where table_name='T'
and column_name='VAL1';

/*
LOW_VALUE HIGH_VALUE
---------- ----------
         4       3295
*/

begin
  dbms_stats.gather_index_stats(ownname =>user, indname =>'T_VAL1_I',estimate_percent=>100);
  end;

select t1.INDEX_NAME,t1.blevel,t1.LEAF_BLOCKS,t1.DISTINCT_KEYS,
t1.NUM_ROWS,t1.CLUSTERING_FACTOR,t1.AVG_LEAF_BLOCKS_PER_KEY,t1.AVG_DATA_BLOCKS_PER_KEY
from user_ind_statistics t1
where t1.TABLE_NAME='T';

/*
INDEX_NAME                         BLEVEL LEAF_BLOCKS DISTINCT_KEYS   NUM_ROWS CLUSTERING_FACTOR AVG_LEAF_BLOCKS_PER_KEY AVG_DATA_BLOCKS_PER_KEY
------------------------------ ---------- ----------- ------------- ---------- ----------------- ----------------------- -----------------------
T_PK                                    1           2          1000       1000               972                       1                       1
T_VAL1_I                                1           2           457        519               508                       1                       1
T_VAL2_I                                1           3             6       1000               174                       1                      29

BLEVEL 访问叶子快而需要读取的分支块的数量,包括根块
LEAF_BLOCKS 索引中的叶子块数量
DISTINCT_KEYS 索引中唯一键值总数
NUM_ROWS 索引中的键值数,对于主键来说 等同于 DISTINCT_KEYS
CLUSTERING_FACTOR 表明有多少临近的索引条目知道不同的数据块。
如果表中数据和索引的排序是相似的,那么 聚簇因子就小。最小值是表中非空数据的数据块总数
如果表中数据和索引的排序迥异,聚簇因子就非常大。最大值是索引中的键值数

*/

select i.index_name,i.clustering_factor,clustering_factor(user,i.table_name,ic.COLUMN_NAME) as my_clstf
from user_indexes i,user_ind_columns ic
where i.table_name='T' and i.index_name=ic.INDEX_NAME;

select * from v$fixed_table;

select * from user_tab_pending_stats;

20170531
0907
--统计信息保留窗口
select dbms_stats.get_stats_history_retention() from dual;

--2.0 修改保留窗口
exec dbms_stats.alter_stats_history_retention(retention=>14);

--3.0 删除14t天之前的统计信息
dbms_stats.purge_stats(before_timestamp=>systimestamp-14);

--执行 2.0  3.0 需要权限 analyze any dictionary

--4.0 确认统计信息是否变动过
select  t1.OWNER,t1.TABLE_NAME,to_char(t1.STATS_UPDATE_TIME,'yyyy-mm-dd hh24:mi:ss') stats_time   from dba_tab_stats_history t1 where t1.owner='OWNER' and t1.TABLE_NAME='T1' order by stats_time desc;

--5.0 恢复单张表的统计信息

dbms_stats.restore_table_stats(ownname=>,
tabname=>,
as_of_timestamp=>,
force=>)

--6.0 修改表的统计信息

exec  dbms_stats.gather_table_stats(ownname=>'OWNER',tabname=>'T1');

select wri.rowcnt,
wri.blkcnt,
wri.avgrln,
wri.analyzetime    from sys.wri$_optstat_tab_history wri,dba_objects obj  where wri.obj#=obj.data_object_id
and  obj.object_name='T1'
 order by wri.analyzetime desc nulls last,obj.subobject_name asc nulls last,
 obj.data_object_id desc nulls last;

select count(1) from  test t1 ;
--71988

select t1.owner,t1.object_name from test t1 where t1.object_id =3389;

SQL> exec dbms_stats.set_table_stats( tabname=>'T1',ownname=>'OWNER',numrows => 2);

PL/SQL procedure successfully completed.

select t1.operation,to_char(t1.START_TIME,'yyyy-mm-dd hh24:mi:ss'), (t1.end_time-t1.start_time)  day(1) to second(0) as duration
from dba_optstat_operations t1
order by t1.start_time desc;

--1528 去人该参数maximum PGA allocated 如果 远远大于 aggregate PGA target parameter ,那么初始化参数 pga_aggregate_target 值 也许不合适了
select name ,value/1024/1024 ,unit from v$pgastat  where name in ('aggregate PGA target parameter','maximum PGA allocated')

--1559
select * from v$sql_plan t1;

select * from v$sql_plan_statistics t1;

select * from v$sql_workarea t1;

select * from v$sql_plan_statistics_all;

--10053 events
alter session set tracefile_identifier='10053';
alter session set events '10053 trace name context forever,level 1';
select * from test;
alter session set events '10053 trace name context off';

--10132 events
alter session set tracefile_identifier='10132';
alter session set events '10132 trace name context forever,level 1';
select * from test;
alter session set events '10132 trace name context off';

--1609 历史执行计划
select * from table(dbms_xplan.display_awr('sql_id'))

--1639
为了使用 display_cursor函数,调用者必须对以下几张动态性能视图有 select权限: V$SESSION 、v$sql、v$sql_plan、v$sql_plan_statistics_all

20170601
 select * from scott.emp where deptno=10 order by ename;

select * from table(dbms_xplan.display(null,null,'advanced'));
select * from table(dbms_xplan.display(null,null,'advanced +iostats last'));
/*
1    Plan hash value: 150391907
2    
3    ---------------------------------------------------------------------------
4    | Id  | Operation          | Name | Rows  | Bytes | Cost (%CPU)| Time     |
5    ---------------------------------------------------------------------------
6    |   0 | SELECT STATEMENT   |      |     5 |   190 |     4  (25)| 00:00:01 |
7    |   1 |  SORT ORDER BY     |      |     5 |   190 |     4  (25)| 00:00:01 |
8    |*  2 |   TABLE ACCESS FULL| EMP  |     5 |   190 |     3   (0)| 00:00:01 |
9    ---------------------------------------------------------------------------
10    
11    Predicate Information (identified by operation id):
12    ---------------------------------------------------
13    
14       2 - filter("DEPTNO"=10)
*/

1030
包含执行计划的表中的字段

基本字段
字段                              描述
id                                每一个操作的标识符。如果数字前面带有星号,意味着该行有谓词信息
operation                         该行的操作,也叫 row source
name                              操作的对象

查询优化器评估类
rows(e-rows)                              评估中操作返回的记录总数
bytes(e-bytes)                            评估中操作返回的字节数
tempspc                                   评估中操作使用的临时空间大小
cost(%cpu)                                评估中操作的开销。括号中是开销的百分比。注意该值是通过执行计划计算过来的。即:福操作的开销包含子操作的开销
time                                      评估中执行操作需要的时间
分区类
pstart                                    访问的第一个分区。如果解析时不知道是哪个分区就设为key、key(i) 、key(mc)、 key(or)、 key(sq)
pstop                                     访问的最后一个分区。如果解析时不知道是哪个分区就设为key、key(i) 、key(mc)、 key(or)、 key(sq)

并行和分布式处理类
starts                                    指定操作执行的次数
a-rows                                    指定操作返回的真实记录数
a-time                                    指定操作执行的真实时间

io统计类
buffers                                   操作期间进行的逻辑读数量
reads                                     操作期间进行的物理读数量
writes                                    操作期间进行的物理写数量

内存使用统计类
omem                                      最有执行所需内存的评估值
imem                                      一次性通过(one-pass)执行所需内存的评估值
used-mem                                  最后一次操作时使用的内存量
user-tmp                                  最后一次操作时使用的临时空间大小

select * from scott.emp where rownum <5;

select * from table(dbms_xplan.display(null,null,'advanced +allstats'));

select * from table(dbms_xplan.display(null,null,'advanced +iostats'));

select * from table(dbms_xplan.display(null,null,'advanced +last'));

select * from table(dbms_xplan.display(null,null,'advanced +memstats'));

select * from table(dbms_xplan.display(null,null,'advanced +runstats_last'));

select * from (select * from scott.emp order by sal desc) where rownum <6;

select * from table(dbms_xplan.display(null,null,'advanced'));

select * from scott.emp,scott.dept where emp.deptno=dept.deptno and emp.comm is null and dept.dname!='SALeES';

select t1.INDEX_NAME,t1.blevel,t1.LEAF_BLOCKS,t1.DISTINCT_KEYS,
t1.NUM_ROWS,t1.CLUSTERING_FACTOR,t1.AVG_LEAF_BLOCKS_PER_KEY,t1.AVG_DATA_BLOCKS_PER_KEY
from user_ind_statistics t1
where t1.TABLE_NAME='TEST';

SELECT index_name,    clustering_factor(user, table_name, column_name) AS clust_factor FROM user_ind_columns  WHERE table_name = 'T';

select * from sys.aux_stats_history;

--SQL> REM Display information about execution statistics (columns Starts, E-Rows,
--SQL> REM A-Rows and A-Time) and I/O operations (columns Buffers, Reads and Writes)

--1. 确认该参数statistics_level 的值
SQL> show parameter statistics_level;

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
statistics_level                     string      TYPICAL  --该参数statistics_level默认值 typical

--2. 修改参数值为 all
SQL> alter session set statistics_level=all;

Session altered.

--3. 再次确认该参数值
SQL> show parameter statistics_level;

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
statistics_level                     string      ALL

/*
执行计划中 Starts 、 E-Rows 、A-Rows 、   A-Time   、Buffers 、 Reads  、 Writes 等参数只在 statistics_level=all的情况下才可以看到值。
*/

--以下开始测试
select * from data_skew;
以下分为 case1、case2、case3、case4、case5

--case 1 iostats last
SELECT * FROM table(dbms_xplan.display_cursor('4y4a4kxntcmsf',0,'iostats last'));
/*
1  SQL_ID  6rwckvk4d8xjb, child number 0
2  -------------------------------------
3  SELECT \*+ gather_plan_statistics *\ count(pad) FROM (SELECT \*
4  parallel(t,2) *\ rownum AS rn, pad       FROM t       ORDER BY n) WHERE
5  rn = 1
6   
7  Plan hash value: 2056542717
8   
9  -----------------------------------------------------------------------------------------------------------
10  | Id  | Operation              | Name | Starts | E-Rows | A-Rows |   A-Time   | Buffers | Reads  | Writes |
11  -----------------------------------------------------------------------------------------------------------
12  |   0 | SELECT STATEMENT       |      |      1 |        |      1 |00:00:00.03 |     153 |    126 |    126 |
13  |   1 |  SORT AGGREGATE        |      |      1 |      1 |      1 |00:00:00.03 |     153 |    126 |    126 |
14  |*  2 |   VIEW                 |      |      1 |    894 |      1 |00:00:00.03 |     153 |    126 |    126 |
15  |   3 |    SORT ORDER BY       |      |      1 |    894 |   1000 |00:00:00.04 |     153 |    126 |    126 |
16  |   4 |     COUNT              |      |      1 |        |   1000 |00:00:00.01 |     150 |      0 |      0 |
17  |   5 |      PARTITION HASH ALL|      |      1 |    894 |   1000 |00:00:00.01 |     150 |      0 |      0 |
18  |   6 |       TABLE ACCESS FULL| T    |      2 |    894 |   1000 |00:00:00.01 |     150 |      0 |      0 |
19  -----------------------------------------------------------------------------------------------------------
20    
21    Predicate Information (identified by operation id):
22    ---------------------------------------------------
23    
24       2 - filter("RN"=1)
25    
26    Note
27    -----
28       - dynamic sampling used for this statement (level=2)
29    
*/

--case 2 advanced
SELECT * FROM table(dbms_xplan.display_cursor('cahbf3stcpj2g',0,'advanced'));
/*
1    SQL_ID  6rwckvk4d8xjb, child number 0
2    -------------------------------------
3    SELECT \*+ gather_plan_statistics *\ count(pad) FROM (SELECT \*
4    parallel(t,2) *\ rownum AS rn, pad       FROM t       ORDER BY n) WHERE
5    rn = 1
6    
7    Plan hash value: 2056542717
8    
9    -------------------------------------------------------------------------------------------------------
10    | Id  | Operation              | Name | Rows  | Bytes |TempSpc| Cost (%CPU)| Time     | Pstart| Pstop |
11    -------------------------------------------------------------------------------------------------------
12    |   0 | SELECT STATEMENT       |      |       |       |       |   139 (100)|          |       |       |
13    |   1 |  SORT AGGREGATE        |      |     1 |   515 |       |            |          |       |       |
14    |*  2 |   VIEW                 |      |   894 |   449K|       |   139   (2)| 00:00:01 |       |       |
15    |   3 |    SORT ORDER BY       |      |   894 |   449K|   488K|   139   (2)| 00:00:01 |       |       |
16    |   4 |     COUNT              |      |       |       |       |            |          |       |       |
17    |   5 |      PARTITION HASH ALL|      |   894 |   449K|       |    19   (0)| 00:00:01 |     1 |     2 |
18    |   6 |       TABLE ACCESS FULL| T    |   894 |   449K|       |    19   (0)| 00:00:01 |     1 |     2 |
19    -------------------------------------------------------------------------------------------------------
20    
21    Query Block Name / Object Alias (identified by operation id):
22    -------------------------------------------------------------
23    
24       1 - SEL$1
*/

--case 3 typical
SELECT * FROM table(dbms_xplan.display_cursor('cahbf3stcpj2g',0,'typical'));
/*
1    SQL_ID  6rwckvk4d8xjb, child number 0
2    -------------------------------------
3    SELECT \*+ gather_plan_statistics *\ count(pad) FROM (SELECT \*
4    parallel(t,2) *\ rownum AS rn, pad       FROM t       ORDER BY n) WHERE
5    rn = 1
6    
7    Plan hash value: 2056542717
8    
9    -------------------------------------------------------------------------------------------------------
10    | Id  | Operation              | Name | Rows  | Bytes |TempSpc| Cost (%CPU)| Time     | Pstart| Pstop |
11    -------------------------------------------------------------------------------------------------------
12    |   0 | SELECT STATEMENT       |      |       |       |       |   139 (100)|          |       |       |
13    |   1 |  SORT AGGREGATE        |      |     1 |   515 |       |            |          |       |       |
14    |*  2 |   VIEW                 |      |   894 |   449K|       |   139   (2)| 00:00:01 |       |       |
15    |   3 |    SORT ORDER BY       |      |   894 |   449K|   488K|   139   (2)| 00:00:01 |       |       |
16    |   4 |     COUNT              |      |       |       |       |            |          |       |       |
17    |   5 |      PARTITION HASH ALL|      |   894 |   449K|       |    19   (0)| 00:00:01 |     1 |     2 |
18    |   6 |       TABLE ACCESS FULL| T    |   894 |   449K|       |    19   (0)| 00:00:01 |     1 |     2 |
19    -------------------------------------------------------------------------------------------------------
20    
21    Predicate Information (identified by operation id):
22    ---------------------------------------------------
23    
24       2 - filter("RN"=1)
25    
26    Note
27    -----
28       - dynamic sampling used for this statement (level=2)
29    
*/

--case 4 all
SELECT * FROM table(dbms_xplan.display_cursor('cahbf3stcpj2g',0,'all'));
/*
1    SQL_ID  6rwckvk4d8xjb, child number 0
2    -------------------------------------
3    SELECT \*+ gather_plan_statistics *\ count(pad) FROM (SELECT \*
4    parallel(t,2) *\ rownum AS rn, pad       FROM t       ORDER BY n) WHERE
5    rn = 1
6    
7    Plan hash value: 2056542717
8    
9    -------------------------------------------------------------------------------------------------------
10    | Id  | Operation              | Name | Rows  | Bytes |TempSpc| Cost (%CPU)| Time     | Pstart| Pstop |
11    -------------------------------------------------------------------------------------------------------
12    |   0 | SELECT STATEMENT       |      |       |       |       |   139 (100)|          |       |       |
13    |   1 |  SORT AGGREGATE        |      |     1 |   515 |       |            |          |       |       |
14    |*  2 |   VIEW                 |      |   894 |   449K|       |   139   (2)| 00:00:01 |       |       |
15    |   3 |    SORT ORDER BY       |      |   894 |   449K|   488K|   139   (2)| 00:00:01 |       |       |
16    |   4 |     COUNT              |      |       |       |       |            |          |       |       |
17    |   5 |      PARTITION HASH ALL|      |   894 |   449K|       |    19   (0)| 00:00:01 |     1 |     2 |
18    |   6 |       TABLE ACCESS FULL| T    |   894 |   449K|       |    19   (0)| 00:00:01 |     1 |     2 |
19    -------------------------------------------------------------------------------------------------------
20    
21    Query Block Name / Object Alias (identified by operation id):
22    -------------------------------------------------------------
23    
24       1 - SEL$1
25       2 - SEL$2 / from$_subquery$_001@SEL$1
26       3 - SEL$2
27       6 - SEL$2 / T@SEL$2
28    
29    Predicate Information (identified by operation id):
30    ---------------------------------------------------
31    
32       2 - filter("RN"=1)
33    
34    Column Projection Information (identified by operation id):
35    -----------------------------------------------------------
36    
37       1 - (#keys=0) COUNT("PAD")[22]
38       2 - "RN"[NUMBER,22], "PAD"[VARCHAR2,1000]
39       3 - (#keys=1) "N"[NUMBER,22], ROWNUM[22], "PAD"[VARCHAR2,1000]
40       4 - "N"[NUMBER,22], "PAD"[VARCHAR2,1000], ROWNUM[4]
41       5 - "N"[NUMBER,22], "PAD"[VARCHAR2,1000]
42       6 - "N"[NUMBER,22], "PAD"[VARCHAR2,1000]
43    
44    Note
45    -----
46       - dynamic sampling used for this statement (level=2)
47    
*/

--case 5 memstats last
SELECT * FROM table(dbms_xplan.display_cursor('cahbf3stcpj2g',0,'memstats last'));
/*
1    SQL_ID  6rwckvk4d8xjb, child number 0
2    -------------------------------------
3    SELECT \*+ gather_plan_statistics *\ count(pad) FROM (SELECT \*
4    parallel(t,2) *\ rownum AS rn, pad       FROM t       ORDER BY n) WHERE
5    rn = 1
6    
7    Plan hash value: 2056542717
8    
9    --------------------------------------------------------------------------------------------------------------------
10    | Id  | Operation              | Name | Starts | E-Rows | A-Rows |   A-Time   |  OMem |  1Mem | Used-Mem | Used-Tmp|
11    --------------------------------------------------------------------------------------------------------------------
12    |   0 | SELECT STATEMENT       |      |      1 |        |      1 |00:00:00.03 |       |       |          |         |
13    |   1 |  SORT AGGREGATE        |      |      1 |      1 |      1 |00:00:00.03 |       |       |          |         |
14    |*  2 |   VIEW                 |      |      1 |    894 |      1 |00:00:00.03 |       |       |          |         |
15    |   3 |    SORT ORDER BY       |      |      1 |    894 |   1000 |00:00:00.04 |  1134K|   560K|74752  (1)|    1024 |
16    |   4 |     COUNT              |      |      1 |        |   1000 |00:00:00.01 |       |       |          |         |
17    |   5 |      PARTITION HASH ALL|      |      1 |    894 |   1000 |00:00:00.01 |       |       |          |         |
18    |   6 |       TABLE ACCESS FULL| T    |      2 |    894 |   1000 |00:00:00.01 |       |       |          |         |
19    --------------------------------------------------------------------------------------------------------------------
20    
21    Predicate Information (identified by operation id):
22    ---------------------------------------------------
23    
24       2 - filter("RN"=1)
25    
26    Note
27    -----
28       - dynamic sampling used for this statement (level=2)
29    
*/

/*
添加 hint   /*+ gather_plan_statistics */
SELECT * FROM table(dbms_xplan.display_cursor(NULL,NULL,'runstats_last'));
以 runstats_last的方式查看执行计划 同样可以返回 execution statistics (columns Starts, E-Rows,
SQL> REM A-Rows and A-Time) and I/O operations (columns Buffers, Reads and Writes)
*/

select /*+ gather_plan_statistics */  object_name from test0605;
select * from table(dbms_xplan.display_cursor(null,null,'advanced'));

select * from test0605;

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