[20220125]生產系統怪異的查詢語句.txt

lfree 發表於 2022-01-25

[20220125]生產系統怪異的查詢語句.txt

--//生產系統有一些程式設計工具會執行一些怪異的查詢語句,檢查生產系統時發現一些奇怪的語句.

1.環境:
> @ prxx
==============================
PORT_STRING                   : x86_64/Linux 2.4.xx
VERSION                       : 19.0.0.0.0
BANNER                        : Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
BANNER_FULL                   : Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.9.0.0.0
BANNER_LEGACY                 : Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
CON_ID                        : 0

PL/SQL procedure successfully completed.

> @ashtop sql_id,event,module,machine  sql_id='9rzcqu8p5uu97'  sysdate-1 sysdate
    Total                                                                                                                                                 Distinct Distinct
  Seconds     AAS %This   SQL_ID        EVENT                       MODULE               MACHINE                FIRST_SEEN          LAST_SEEN           Execs Seen  Tstamps
--------- ------- ------- ------------- --------------------------- -------------------- ---------------------- ------------------- ------------------- ---------- --------
      388      .0  100% | 9rzcqu8p5uu97                             JDBC Thin Client     localhost.localdomain  2022-01-24 09:23:42 2022-01-25 09:18:28        388      388


> @ sqlhh 9rzcqu8p5uu97
BEGIN_INTERVAL_TIME    INST_ID SQL_ID        PLAN_HASH_VALUE EXECUTIONS ELA_MS_PER_EXEC CPU_MS_PER_EXEC ROWS_PER_EXEC LIOS_PER_EXEC BLKRD_PER_EXEC IOW_MS_PER_EXEC  AVG_IOW_MS CLW_MS_PER_EXEC APW_MS_PER_EXEC CCW_MS_PER_EXEC
------------------- ---------- ------------- --------------- ---------- --------------- --------------- ------------- ------------- -------------- --------------- ----------- --------------- --------------- ---------------
2021-11-25 22:00:32          1 9rzcqu8p5uu97      1279168831        715              29              28           6.0          1445              0               0         0.0               0               0               0
2021-11-25 23:00:04          1 9rzcqu8p5uu97      1279168831        721              29              28           6.0          1445              0               0         0.0               0               0               0
...
2022-01-25 07:00:01          2 9rzcqu8p5uu97      1279168831        724              29              28           6.0          1445              0               0         0.0               0               0               0
2022-01-25 08:00:20          2 9rzcqu8p5uu97      1279168831        724              29              29           6.0          1445              0               0         0.0               0               0               0

1563 rows selected.
--//基本每個小時執行72X次.3600/720 = 5.每5秒執行1次.

[email protected]:17102/dyhis> @ sql_id 9rzcqu8p5uu97
--SQL_ID = 9rzcqu8p5uu97
SELECT column_name as Field , data_type as Type  FROM all_tab_cols WHERE lower(table_name) = 'view_lb_doctor_login';

--//使用謂詞lower(table_name) = 'view_lb_doctor_login',不知道為什麼使用小寫函式,直接導致每次掃描sys.obj$.

Plan hash value: 1279168831
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
| Id  | Operation                               | Name              | Starts | E-Rows |E-Bytes| Cost (%CPU)| E-Time   | A-Rows |   A-Time   | Buffers |  OMem |  1Mem | Used-Mem |
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT                        |                   |      1 |        |       |   541 (100)|          |      6 |00:00:00.03 |    1445 |       |       |          |
|   1 |  TABLE ACCESS BY INDEX ROWID BATCHED    | OBJ$              |      0 |      1 |    38 |     3   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|*  2 |   INDEX RANGE SCAN                      | I_OBJ1            |      0 |      1 |       |     2   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|   3 |   TABLE ACCESS BY INDEX ROWID BATCHED   | OBJ$              |      0 |      1 |    38 |     3   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|*  4 |    INDEX RANGE SCAN                     | I_OBJ1            |      0 |      1 |       |     2   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|   5 |    TABLE ACCESS BY INDEX ROWID BATCHED  | OBJ$              |      0 |      1 |    38 |     3   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|*  6 |     INDEX RANGE SCAN                    | I_OBJ1            |      0 |      1 |       |     2   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|   7 |     TABLE ACCESS BY INDEX ROWID BATCHED | OBJ$              |      0 |      1 |    38 |     3   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|*  8 |      INDEX RANGE SCAN                   | I_OBJ1            |      0 |      1 |       |     2   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|   9 |      TABLE ACCESS BY INDEX ROWID BATCHED| OBJ$              |      0 |      1 |    38 |     3   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|* 10 |       INDEX RANGE SCAN                  | I_OBJ1            |      0 |      1 |       |     2   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|* 11 |  FILTER                                 |                   |      1 |        |       |            |          |      6 |00:00:00.03 |    1445 |       |       |          |
|* 12 |   HASH JOIN OUTER                       |                   |      1 |     27 |  5427 |   526   (1)| 00:00:01 |      6 |00:00:00.03 |    1441 |   970K|   970K|  463K (0)|
|  13 |    NESTED LOOPS OUTER                   |                   |      1 |     27 |  5319 |   525   (1)| 00:00:01 |      6 |00:00:00.03 |    1440 |       |       |          |
|  14 |     NESTED LOOPS OUTER                  |                   |      1 |     27 |  5049 |   498   (1)| 00:00:01 |      6 |00:00:00.03 |    1431 |       |       |          |
|  15 |      NESTED LOOPS OUTER                 |                   |      1 |     27 |  3915 |   390   (1)| 00:00:01 |      6 |00:00:00.03 |    1431 |       |       |          |
|  16 |       NESTED LOOPS                      |                   |      1 |     27 |  3159 |   389   (1)| 00:00:01 |      6 |00:00:00.03 |    1423 |       |       |          |
|* 17 |        HASH JOIN                        |                   |      1 |      2 |   174 |   388   (1)| 00:00:01 |      2 |00:00:00.03 |    1418 |  1209K|  1209K|  858K (0)|
|* 18 |         HASH JOIN                       |                   |      1 |      2 |   166 |   387   (1)| 00:00:01 |      2 |00:00:00.03 |    1417 |  1265K|  1265K|  881K (0)|
|  19 |          NESTED LOOPS OUTER             |                   |      1 |      2 |   118 |   386   (1)| 00:00:01 |      2 |00:00:00.03 |    1416 |       |       |          |
|* 20 |           TABLE ACCESS FULL             | OBJ$              |      1 |      2 |   108 |   385   (1)| 00:00:01 |      2 |00:00:00.03 |    1411 |       |       |          |
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|  21 |           TABLE ACCESS CLUSTER          | TAB$              |      2 |      1 |     5 |     1   (0)| 00:00:01 |      0 |00:00:00.01 |       5 |       |       |          |
|* 22 |            INDEX UNIQUE SCAN            | I_OBJ#            |      2 |      1 |       |     0   (0)|          |      1 |00:00:00.01 |       4 |       |       |          |
|  23 |          INDEX FULL SCAN                | I_USER2           |      1 |    143 |  3432 |     1   (0)| 00:00:01 |    143 |00:00:00.01 |       1 |       |       |          |
|  24 |         INDEX FULL SCAN                 | I_USER2           |      1 |    143 |   572 |     1   (0)| 00:00:01 |    143 |00:00:00.01 |       1 |       |       |          |
|  25 |        TABLE ACCESS CLUSTER             | COL$              |      2 |     14 |   420 |     1   (0)| 00:00:01 |      6 |00:00:00.01 |       5 |       |       |          |
|* 26 |         INDEX UNIQUE SCAN               | I_OBJ#            |      2 |      1 |       |     0   (0)|          |      1 |00:00:00.01 |       4 |       |       |          |
|  27 |       TABLE ACCESS BY INDEX ROWID       | COLTYPE$          |      6 |      1 |    28 |     1   (0)| 00:00:01 |      0 |00:00:00.01 |       8 |       |       |          |
|* 28 |        INDEX UNIQUE SCAN                | I_COLTYPE2        |      6 |      1 |       |     0   (0)|          |      0 |00:00:00.01 |       8 |       |       |          |
|* 29 |      TABLE ACCESS BY INDEX ROWID BATCHED| OBJ$              |      6 |      1 |    42 |     4   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|* 30 |       INDEX RANGE SCAN                  | I_OBJ3            |      6 |     24 |       |     1   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|* 31 |     INDEX RANGE SCAN                    | I_HH_OBJ#_INTCOL# |      6 |      1 |    10 |     1   (0)| 00:00:01 |      0 |00:00:00.01 |       9 |       |       |          |
|  32 |    INDEX FULL SCAN                      | I_USER2           |      1 |    143 |   572 |     1   (0)| 00:00:01 |    143 |00:00:00.01 |       1 |       |       |          |
|* 33 |   TABLE ACCESS CLUSTER                  | TAB$              |      0 |      1 |    13 |     2   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|* 34 |    INDEX UNIQUE SCAN                    | I_OBJ#            |      0 |      1 |       |     1   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|  35 |   NESTED LOOPS SEMI                     |                   |      1 |      1 |    12 |     2   (0)| 00:00:01 |      0 |00:00:00.01 |       4 |       |       |          |
|  36 |    FIXED TABLE FULL                     | X$KZSRO           |      1 |      2 |     6 |     0   (0)|          |      2 |00:00:00.01 |       0 |       |       |          |
|* 37 |    INDEX RANGE SCAN                     | I_OBJAUTH2        |      2 |      1 |     9 |     1   (0)| 00:00:01 |      0 |00:00:00.01 |       4 |       |       |          |
|* 38 |   FIXED TABLE FULL                      | X$KZSPR           |      1 |      1 |     7 |     0   (0)|          |      1 |00:00:00.01 |       0 |       |       |          |
|* 39 |   TABLE ACCESS BY INDEX ROWID BATCHED   | USER_EDITIONING$  |      0 |      1 |     6 |     2   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|* 40 |    INDEX RANGE SCAN                     | I_USER_EDITIONING |      0 |      2 |       |     1   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|* 41 |   TABLE ACCESS BY INDEX ROWID BATCHED   | USER_EDITIONING$  |      0 |      1 |     6 |     2   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|* 42 |    INDEX RANGE SCAN                     | I_USER_EDITIONING |      0 |      2 |       |     1   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|  43 |   NESTED LOOPS SEMI                     |                   |      0 |      1 |    29 |     2   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|* 44 |    INDEX SKIP SCAN                      | I_USER2           |      0 |      1 |    20 |     1   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|* 45 |    INDEX RANGE SCAN                     | I_OBJ4            |      0 |      1 |     9 |     1   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

--//ID=20全表掃描OBJ$,邏輯讀最大貢獻來之這裡.如果修改如下執行:

SELECT column_name as Field , data_type as Type  FROM all_tab_cols WHERE table_name = 'VIEW_LB_DOCTOR_LOGIN';

Plan hash value: 1626446879

---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
| Id  | Operation                                    | Name              | Starts | E-Rows |E-Bytes| Cost (%CPU)| E-Time   | A-Rows |   A-Time   | Buffers |  OMem |  1Mem | Used-Mem |
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT                             |                   |      1 |        |       |   136 (100)|          |      6 |00:00:00.01 |      72 |       |       |          |
|   1 |  TABLE ACCESS BY INDEX ROWID BATCHED         | OBJ$              |      0 |      1 |    38 |     3   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|*  2 |   INDEX RANGE SCAN                           | I_OBJ1            |      0 |      1 |       |     2   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|   3 |   TABLE ACCESS BY INDEX ROWID BATCHED        | OBJ$              |      0 |      1 |    38 |     3   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|*  4 |    INDEX RANGE SCAN                          | I_OBJ1            |      0 |      1 |       |     2   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|   5 |    TABLE ACCESS BY INDEX ROWID BATCHED       | OBJ$              |      0 |      1 |    38 |     3   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|*  6 |     INDEX RANGE SCAN                         | I_OBJ1            |      0 |      1 |       |     2   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|   7 |     TABLE ACCESS BY INDEX ROWID BATCHED      | OBJ$              |      0 |      1 |    38 |     3   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|*  8 |      INDEX RANGE SCAN                        | I_OBJ1            |      0 |      1 |       |     2   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|   9 |      TABLE ACCESS BY INDEX ROWID BATCHED     | OBJ$              |      0 |      1 |    38 |     3   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|* 10 |       INDEX RANGE SCAN                       | I_OBJ1            |      0 |      1 |       |     2   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|* 11 |  FILTER                                      |                   |      1 |        |       |            |          |      6 |00:00:00.01 |      72 |       |       |          |
|* 12 |   HASH JOIN OUTER                            |                   |      1 |     16 |  3216 |   121   (0)| 00:00:01 |      6 |00:00:00.01 |      68 |   970K|   970K|  506K (0)|
|  13 |    NESTED LOOPS OUTER                        |                   |      1 |     16 |  3152 |   120   (0)| 00:00:01 |      6 |00:00:00.01 |      67 |       |       |          |
|  14 |     NESTED LOOPS OUTER                       |                   |      1 |     16 |  2480 |    56   (0)| 00:00:01 |      6 |00:00:00.01 |      67 |       |       |          |
|  15 |      NESTED LOOPS OUTER                      |                   |      1 |     16 |  2320 |    40   (0)| 00:00:01 |      6 |00:00:00.01 |      58 |       |       |          |
|  16 |       NESTED LOOPS                           |                   |      1 |     16 |  1872 |    39   (0)| 00:00:01 |      6 |00:00:00.01 |      50 |       |       |          |
|* 17 |        HASH JOIN                             |                   |      1 |      1 |    87 |    38   (0)| 00:00:01 |      2 |00:00:00.01 |      45 |  1209K|  1209K|  617K (0)|
|  18 |         NESTED LOOPS                         |                   |      1 |      1 |    83 |    37   (0)| 00:00:01 |      2 |00:00:00.01 |      44 |       |       |          |
|  19 |          NESTED LOOPS OUTER                  |                   |      1 |      1 |    59 |    36   (0)| 00:00:01 |      2 |00:00:00.01 |      42 |       |       |          |
|* 20 |           TABLE ACCESS BY INDEX ROWID BATCHED| OBJ$              |      1 |      1 |    54 |    35   (0)| 00:00:01 |      2 |00:00:00.01 |      37 |       |       |          |
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|* 21 |            INDEX SKIP SCAN                   | I_OBJ2            |      1 |      1 |       |    34   (0)| 00:00:01 |      2 |00:00:00.01 |      35 |       |       |          |
|  22 |           TABLE ACCESS CLUSTER               | TAB$              |      2 |      1 |     5 |     1   (0)| 00:00:01 |      0 |00:00:00.01 |       5 |       |       |          |
|* 23 |            INDEX UNIQUE SCAN                 | I_OBJ#            |      2 |      1 |       |     0   (0)|          |      1 |00:00:00.01 |       4 |       |       |          |
|* 24 |          INDEX RANGE SCAN                    | I_USER2           |      2 |      1 |    24 |     1   (0)| 00:00:01 |      2 |00:00:00.01 |       2 |       |       |          |
|  25 |         INDEX FULL SCAN                      | I_USER2           |      1 |      1 |     4 |     1   (0)| 00:00:01 |    143 |00:00:00.01 |       1 |       |       |          |
|  26 |        TABLE ACCESS CLUSTER                  | COL$              |      2 |     14 |   420 |     1   (0)| 00:00:01 |      6 |00:00:00.01 |       5 |       |       |          |
|* 27 |         INDEX UNIQUE SCAN                    | I_OBJ#            |      2 |      1 |       |     0   (0)|          |      1 |00:00:00.01 |       4 |       |       |          |
|  28 |       TABLE ACCESS BY INDEX ROWID            | COLTYPE$          |      6 |      1 |    28 |     1   (0)| 00:00:01 |      0 |00:00:00.01 |       8 |       |       |          |
|* 29 |        INDEX UNIQUE SCAN                     | I_COLTYPE2        |      6 |      1 |       |     0   (0)|          |      0 |00:00:00.01 |       8 |       |       |          |
|* 30 |      INDEX RANGE SCAN                        | I_HH_OBJ#_INTCOL# |      6 |      1 |    10 |     1   (0)| 00:00:01 |      0 |00:00:00.01 |       9 |       |       |          |
|* 31 |     TABLE ACCESS BY INDEX ROWID BATCHED      | OBJ$              |      6 |      1 |    42 |     4   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|* 32 |      INDEX RANGE SCAN                        | I_OBJ3            |      6 |     24 |       |     1   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|  33 |    INDEX FULL SCAN                           | I_USER2           |      1 |    143 |   572 |     1   (0)| 00:00:01 |    143 |00:00:00.01 |       1 |       |       |          |
|* 34 |   TABLE ACCESS CLUSTER                       | TAB$              |      0 |      1 |    13 |     2   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|* 35 |    INDEX UNIQUE SCAN                         | I_OBJ#            |      0 |      1 |       |     1   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|  36 |   NESTED LOOPS SEMI                          |                   |      1 |      1 |    12 |     2   (0)| 00:00:01 |      0 |00:00:00.01 |       4 |       |       |          |
|  37 |    FIXED TABLE FULL                          | X$KZSRO           |      1 |      2 |     6 |     0   (0)|          |      2 |00:00:00.01 |       0 |       |       |          |
|* 38 |    INDEX RANGE SCAN                          | I_OBJAUTH2        |      2 |      1 |     9 |     1   (0)| 00:00:01 |      0 |00:00:00.01 |       4 |       |       |          |
|* 39 |   FIXED TABLE FULL                           | X$KZSPR           |      1 |      1 |     7 |     0   (0)|          |      1 |00:00:00.01 |       0 |       |       |          |
|* 40 |   TABLE ACCESS BY INDEX ROWID BATCHED        | USER_EDITIONING$  |      0 |      1 |     6 |     2   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|* 41 |    INDEX RANGE SCAN                          | I_USER_EDITIONING |      0 |      2 |       |     1   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|* 42 |   TABLE ACCESS BY INDEX ROWID BATCHED        | USER_EDITIONING$  |      0 |      1 |     6 |     2   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|* 43 |    INDEX RANGE SCAN                          | I_USER_EDITIONING |      0 |      2 |       |     1   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|  44 |   NESTED LOOPS SEMI                          |                   |      0 |      1 |    29 |     2   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|* 45 |    INDEX SKIP SCAN                           | I_USER2           |      0 |      1 |    20 |     1   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
|* 46 |    INDEX RANGE SCAN                          | I_OBJ4            |      0 |      1 |     9 |     1   (0)| 00:00:01 |      0 |00:00:00.01 |       0 |       |       |          |
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

--//雖然使用skip 索引,導致邏輯讀已經大大降低,這種開發工具導致的問題出來起來非常麻煩,你不可能在sys.obj$上建立索引.
--//試想一下如果物件很多,會導致掃描obj$邏輯讀很大,而且我這裡僅僅列舉一個物件的查詢,實際的生產系統可能出現大量的類似的查
--//詢語句.最終的結果導致執行"緩慢".

[email protected]:17102/dyhis> @ d_bufferx 9rzcqu8p5uu97 60 1,2
SQL_ID                INST_ID MODULE            EXECUTIONS        CPU_TIME    ELAPSED_TIME     BUFFER_GETS  ROWS_PROCESSED    CPU_PER_EXEC ELAPSED_TIME_EXEC BUFFER_GETS_EXEC ROWS_PROCESSED_EXEC
------------- --------------- ------------ --------------- --------------- --------------- --------------- --------------- --------------- ----------------- ---------------- -------------------
9rzcqu8p5uu97               2 JDBC Thin Cl              12          341455          351409           17340              72 28454.583333333   29284.083333333             1445                   6
                              ient
--//與前面預測一致.

[email protected]:17102/dyhis> @ d_bufferx awa8nszb02q6p 60 1,2
SQL_ID                INST_ID MODULE            EXECUTIONS        CPU_TIME    ELAPSED_TIME     BUFFER_GETS  ROWS_PROCESSED    CPU_PER_EXEC ELAPSED_TIME_EXEC BUFFER_GETS_EXEC ROWS_PROCESSED_EXEC
------------- --------------- ------------ --------------- --------------- --------------- --------------- --------------- --------------- ----------------- ---------------- -------------------
awa8nszb02q6p               1 JDBC Thin Cl               0               0               0               0               0
                              ient

awa8nszb02q6p               2 JDBC Thin Cl               6          244427          248116           11460               0 40737.833333333   41352.666666667             1910                   0
                              ient

--//這個僅僅是其中1個,平均10秒出現1次.
--//如果真的很多,只能冒很大的風險改名檢視,建立一個真實的表all_tab_cols以及相關索引來欺騙系統,但是帶來維護的問題.

來自 “ ITPUB部落格 ” ,連結:http://blog.itpub.net/267265/viewspace-2853888/,如需轉載,請註明出處,否則將追究法律責任。