[20191213]toad 12下BIND_AWARE提示无效.txt

大家好，我是考100分的小小码，祝大家学习进步，加薪顺利呀。今天说一说[20191213]toad 12下BIND_AWARE提示无效.txt,希望您对编程的造诣更进一步.

[20191213]toad 12下BIND_AWARE提示无效.txt

–//链接http://blog.itpub.net/267265/viewspace-2130781/的测试,发现当时测试的错误.有空再次验证看看.

1.环境:
SCOTT@book> @ ver1
PORT_STRING VERSION BANNER
—————————— ————– ——————————————————————————–
x86_64/Linux 2.4.xx 11.2.0.4.0 Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 – 64bit Production

create table t as select rownum id ,lpad(“x”,100,”x”) name ,lpad(“1”,1) flag from dual connect by level<=1e5;
update t set flag=”0″ where id=1e5;
commit ;
create index i_t_flag on t(flag);

SCOTT@book> execute sys.dbms_stats.gather_table_stats ( OwnName => “”,TabName => “t”,Estimate_Percent => NULL,Method_Opt => “FOR ALL COLUMNS SIZE 1 for columns flag size 4”,Cascade => True ,No_Invalidate => false)
PL/SQL procedure successfully completed.

2.测试:
–//先写sql语句在toad sql编辑窗口:
select /*+ bind_aware gggg*/ * from t where flag=:x;
–//然后选择执行,代入参数”0″.查询字串gggg,获取sql_id=ddgfa29wynq6d.

SCOTT@book> @ dpc ddgfa29wynq6d outline
PLAN_TABLE_OUTPUT
————————————-
SQL_ID ddgfa29wynq6d, child number 0
————————————-
select /*+ bind_aware gggg*/ * from t where flag=:x
Plan hash value: 1601196873
—————————————————————————
| Id | Operation         | Name | E-Rows |E-Bytes| Cost (%CPU)| E-Time   |
—————————————————————————
|   0 | SELECT STATEMENT |      |        |       |   435 (100)|          |
|* 1 | TABLE ACCESS FULL| T    | 50000 | 5273K|   435   (1)| 00:00:06 |
—————————————————————————
Query Block Name / Object Alias (identified by operation id):
————————————————————-
   1 – SEL$1 / T@SEL$1
Outline Data
————-
/*+
      BEGIN_OUTLINE_DATA
      IGNORE_OPTIM_EMBEDDED_HINTS
      OPTIMIZER_FEATURES_ENABLE(“11.2.0.4”)
      DB_VERSION(“11.2.0.4”)
      OPT_PARAM(“_optim_peek_user_binds” “false”)
      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      ALL_ROWS
      OUTLINE_LEAF(@”SEL$1″)
      FULL(@”SEL$1″ “T”@”SEL$1”)
      END_OUTLINE_DATA
*/
Predicate Information (identified by operation id):
—————————————————
   1 – filter(“FLAG”=:X)

–//注意看下划线,不知道为什么toad要加入修改参数”_optim_peek_user_binds” “false”,不做绑定变量peek,
–//还可以一个细节就是没有获取绑定变量的值.导致提示bind_aware失效.

3.继续测试:
–//取消load cached plan if possible.看到的测试结果也是一样.
–//总之不知道为什么toad 12的版本为什么执行时将会话的_optim_peek_user_binds=false.而导致的提示失效.
–//这个应该在优化与调试sql语句是应该引起注意.
–//另外一个简单的验证就是在sqlplus执行:
SCOTT@book> variable x varchar2(1)
SCOTT@book> exec :x := “0”;
PL/SQL procedure successfully completed.

SCOTT@book> @ dpc “” outline
PLAN_TABLE_OUTPUT
————————————-
SQL_ID 8srddvbs5ydfv, child number 0
————————————-
select /*+ bind_aware OPT_PARAM(“_optim_peek_user_binds” “false”) */ *
from t where flag=:x
Plan hash value: 1601196873
—————————————————————————
| Id | Operation         | Name | E-Rows |E-Bytes| Cost (%CPU)| E-Time   |
—————————————————————————
|   0 | SELECT STATEMENT |      |        |       |   435 (100)|          |
|* 1 | TABLE ACCESS FULL| T    | 50000 | 5273K|   435   (1)| 00:00:06 |
—————————————————————————
Query Block Name / Object Alias (identified by operation id):
————————————————————-
   1 – SEL$1 / T@SEL$1
Outline Data
————-
/*+
      BEGIN_OUTLINE_DATA
      IGNORE_OPTIM_EMBEDDED_HINTS
      OPTIMIZER_FEATURES_ENABLE(“11.2.0.4”)
      DB_VERSION(“11.2.0.4”)
      OPT_PARAM(“_optim_peek_user_binds” “false”)
      ALL_ROWS
      OUTLINE_LEAF(@”SEL$1″)
      FULL(@”SEL$1″ “T”@”SEL$1”)
      END_OUTLINE_DATA
*/
Predicate Information (identified by operation id):
—————————————————
   1 – filter(“FLAG”=:X)

–//bind_aware提示无效.
–//如果语句在sqlplus下先执行再在toad下观察呢?
SCOTT@book> select /*+ bind_aware pppp */ * from t where flag=:x;
        ID NAME                                     F
———- —————————————- –
    100000 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx 0
           xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
           xxxxxxxxxxxxxxxxxxxx

SCOTT@book> @ dpc “” “”
PLAN_TABLE_OUTPUT
————————————-
SQL_ID 8b15sjx54pvfw, child number 0
————————————-
select /*+ bind_aware pppp */ * from t where flag=:x

Plan hash value: 120143814

—————————————————————————————–
| Id | Operation                   | Name     | E-Rows |E-Bytes| Cost (%CPU)| E-Time   |
—————————————————————————————–
|   0 | SELECT STATEMENT            |          |        |       |     2 (100)|          |
|   1 | TABLE ACCESS BY INDEX ROWID| T        |      1 |   108 |     2   (0)| 00:00:01 |
|* 2 |   INDEX RANGE SCAN          | I_T_FLAG |      1 |       |     1   (0)| 00:00:01 |
—————————————————————————————–

–//然后在toad下执行,代入参数”0″;

SQL_ID 8b15sjx54pvfw, child number 0
————————————-
select /*+ bind_aware pppp */ * from t where flag=:x

Plan hash value: 120143814

—————————————————————————————–
| Id | Operation                   | Name     | E-Rows |E-Bytes| Cost (%CPU)| E-Time   |
—————————————————————————————–
|   0 | SELECT STATEMENT            |          |        |       |     2 (100)|          |
|   1 | TABLE ACCESS BY INDEX ROWID| T        |      1 |   108 |     2   (0)| 00:00:01 |
|* 2 |   INDEX RANGE SCAN          | I_T_FLAG |      1 |       |     1   (0)| 00:00:01 |
—————————————————————————————–

Query Block Name / Object Alias (identified by operation id):
————————————————————-

   1 – SEL$1 / T@SEL$1
   2 – SEL$1 / T@SEL$1

Outline Data
————-

/*+
      BEGIN_OUTLINE_DATA
      IGNORE_OPTIM_EMBEDDED_HINTS
      OPTIMIZER_FEATURES_ENABLE(“11.2.0.4”)
      DB_VERSION(“11.2.0.4”)
      ALL_ROWS
      OUTLINE_LEAF(@”SEL$1″)
      INDEX_RS_ASC(@”SEL$1″ “T”@”SEL$1” (“T”.”FLAG”))
      END_OUTLINE_DATA
*/

Peeked Binds (identified by position):
————————————–

   1 – (VARCHAR2(30), CSID=852): “0”

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

   2 – access(“FLAG”=:X)

Column Projection Information (identified by operation id):
———————————————————–

   1 – “T”.”ID”[NUMBER,22], “T”.”NAME”[VARCHAR2,100], “FLAG”[VARCHAR2,1]
   2 – “T”.ROWID[ROWID,10], “FLAG”[VARCHAR2,1]

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

SQL_ID 8b15sjx54pvfw, child number 1
————————————-
select /*+ bind_aware pppp */ * from t where flag=:x

Plan hash value: 1601196873

—————————————————————————
| Id | Operation         | Name | E-Rows |E-Bytes| Cost (%CPU)| E-Time   |
—————————————————————————
|   0 | SELECT STATEMENT |      |        |       |   435 (100)|          |
|* 1 | TABLE ACCESS FULL| T    | 50000 | 5273K|   435   (1)| 00:00:06 |
—————————————————————————

Query Block Name / Object Alias (identified by operation id):
————————————————————-

   1 – SEL$1 / T@SEL$1

Outline Data
————-

/*+
      BEGIN_OUTLINE_DATA
      IGNORE_OPTIM_EMBEDDED_HINTS
      OPTIMIZER_FEATURES_ENABLE(“11.2.0.4”)
      DB_VERSION(“11.2.0.4”)
      OPT_PARAM(“_optim_peek_user_binds” “false”)
      ALL_ROWS
      OUTLINE_LEAF(@”SEL$1″)
      FULL(@”SEL$1″ “T”@”SEL$1”)
      END_OUTLINE_DATA
*/

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

   1 – filter(“FLAG”=:X)

Column Projection Information (identified by operation id):
———————————————————–

   1 – “T”.”ID”[NUMBER,22], “T”.”NAME”[VARCHAR2,100], “FLAG”[VARCHAR2,1]

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