作者：eygle |English 【转载时请标明出处和作者信息】|【恩墨学院 OCM培训传DBA成功之道】
链接：http://www.eygle.com/archives/2017/08/dbms_sqltune_util0_sqltext_to_sqlid.html
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在 Oracle 数据库中，如何得到给定SQL的 SQL_ID ? 这是曾经被广泛讨论的一个问题。
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现在，在Oracle 11g中，Oracle 给出了一个系统包，通过 dbms_sqltune_util0 可以简便的计算出给定SQL的SQL_ID。
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SQL> desc dbms_sqltune_util0
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FUNCTION EXTRACT_BIND RETURNS SQL_BIND
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Argument Name Type In/Out Default?
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------------------------------ ----------------------- ------ --------
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BIND_DATA RAW IN
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BIND_POS BINARY_INTEGER IN
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FUNCTION EXTRACT_BINDS RETURNS SQL_BIND_SET
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Argument Name Type In/Out Default?
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------------------------------ ----------------------- ------ --------
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BIND_DATA RAW IN
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FUNCTION GET_BINDS_COUNT RETURNS BINARY_INTEGER
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Argument Name Type In/Out Default?
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------------------------------ ----------------------- ------ --------
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BIND_DATA RAW IN
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FUNCTION IS_BIND_MASKED RETURNS NUMBER
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Argument Name Type In/Out Default?
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------------------------------ ----------------------- ------ --------
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BIND_POS BINARY_INTEGER IN
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MASKED_BINDS_FLAG RAW IN DEFAULT
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FUNCTION SQLTEXT_TO_SIGNATURE RETURNS NUMBER
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Argument Name Type In/Out Default?
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------------------------------ ----------------------- ------ --------
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SQL_TEXT CLOB IN
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FORCE_MATCH BINARY_INTEGER IN DEFAULT
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FUNCTION SQLTEXT_TO_SQLID RETURNS VARCHAR2
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Argument Name Type In/Out Default?
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------------------------------ ----------------------- ------ --------
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SQL_TEXT CLOB IN
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FUNCTION VALIDATE_SQLID RETURNS BINARY_INTEGER
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Argument Name Type In/Out Default?
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------------------------------ ----------------------- ------ --------
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SQL_ID VARCHAR2 IN
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函数 sqltext_to_sqlid 用于实现这个功能，以下测试使用了一个简单的SQL查询。
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注意Oracle在SQL最后加入一个 chr(0) 的不可见字符，我们需要补齐：
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SYS@ r7>SELECT DBMS_SQLTUNE_UTIL0.SQLTEXT_TO_SQLID('SELECT SYSDATE FROM DUAL'||CHR(0)) SQL_ID FROM DUAL;
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SQL_ID
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c749bc43qqfz3
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接下来看一下执行这个查询，数据库中自动生成的SQL_ID，与通过函数转换生成的完全一致：
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SYS@ r7>SELECT SYSDATE FROM DUAL;
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SYSDATE
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21-AUG-17
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SYS@ r7>SELECT SQL_ID FROM V$SQL WHERE SQL_TEXT='SELECT SYSDATE FROM DUAL';
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SQL_ID
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c749bc43qqfz3
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查看执行计划
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SYS@ r7>select * from table(dbms_xplan.display_cursor('c749bc43qqfz3'));
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PLAN_TABLE_OUTPUT
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----------------------------------------------------------------------------------------------------------------------------------------------------------------
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SQL_ID c749bc43qqfz3, child number 0
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SELECT SYSDATE FROM DUAL
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Plan hash value: 1388734953
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-----------------------------------------------------------------
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| Id | Operation | Name | Rows | Cost (%CPU)| Time |
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-----------------------------------------------------------------
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| 0 | SELECT STATEMENT | | | 2 (100)| |
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| 1 | FAST DUAL | | 1 | 2 (0)| 00:00:01 |
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-----------------------------------------------------------------
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13 rows selected.
