數據庫中如何驗證SQL ID與SQL HASH VALUE轉換

這篇文章主要介紹了數據庫中如何驗證SQL ID與SQL HASH VALUE轉換，具有一定借鑒價值，感興趣的朋友可以參考下，希望大家閱讀完這篇文章之后大有收獲，下面讓小編帶著大家一起了解一下。

實驗目的：驗證SQL ID與SQL HASH VALUE轉換

SQL> set linesize 1000

SQL> select count(1) from tab_01;

  COUNT(1)

----------

     85128

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

PLAN_TABLE_OUTPUT

------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

SQL_ID  6mhbq2s7z9ydn, child number 0

-------------------------------------

select count(1) from tab_01

Plan hash value: 4218700832

---------------------------------------------------------------------

| Id  | Operation          | Name   | Rows  | Cost (%CPU)| Time     |

---------------------------------------------------------------------

|   0 | SELECT STATEMENT   |        |       |   342 (100)|          |

|   1 |  SORT AGGREGATE    |        |     1 |            |          |

PLAN_TABLE_OUTPUT

------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|   2 |   TABLE ACCESS FULL| TAB_01 | 85128 |   342   (1)| 00:00:01 |

---------------------------------------------------------------------

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

-------------------------------------------------------------

   1 - SEL$1

   2 - SEL$1 / TAB_01@SEL$1

Outline Data

-------------

PLAN_TABLE_OUTPUT

------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

  /*+

      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")

      FULL(@"SEL$1" "TAB_01"@"SEL$1")

      END_OUTLINE_DATA

  */

PLAN_TABLE_OUTPUT

------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Column Projection Information (identified by operation id):

-----------------------------------------------------------

   1 - (#keys=0) COUNT(*)[22]

已選擇39行。

SQL> select sql_text,sql_id,hash_value,child_number from v$sql where sql_text like 'select count(1) from tab_01%';

SQL_TEXT

----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

SQL_ID                     HASH_VALUE CHILD_NUMBER

-------------------------- ---------- ------------

select count(1) from tab_01

6mhbq2s7z9ydn               267712948            0

SQL> select lower(trim('6mhbq2s7z9ydn')) sql_id,trunc(mod(sum((instr('0123456789abcdfghjkmnpqrstuvwxyz',substr(lower(trim('6mhbq2s7z9ydn ')), level, 1)) - 1) *

  2       power(32, length(trim('6mhbq2s7z9ydn ')) - level)), power(2, 32))) hash_value  from dual  connect by level <= length(trim('6mhbq2s7z9ydn'));

SQL_ID                     HASH_VALUE

-------------------------- ----------

6mhbq2s7z9ydn               267712948

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