Comments on: Why does even a small difference in SQL text cause a hard parse? http://blog.tanelpoder.com/2008/08/15/why-does-even-a-small-difference-in-sql-text-cause-a-hard-parse/ Oracle troubleshooting, internals and performance tuning Mon, 15 Mar 2010 01:50:11 +0000 http://wordpress.org/?v=2.9.2 hourly 1 By: Asif Momen http://blog.tanelpoder.com/2008/08/15/why-does-even-a-small-difference-in-sql-text-cause-a-hard-parse/comment-page-1/#comment-515 Asif Momen Fri, 15 Aug 2008 12:16:27 +0000 http://tanelpoder.wordpress.com/2008/08/15/why-does-even-a-small-difference-in-sql-text-cause-a-hard-parse/#comment-515 Nice post !!! Nice post !!!

]]> By: tanelp http://blog.tanelpoder.com/2008/08/15/why-does-even-a-small-difference-in-sql-text-cause-a-hard-parse/comment-page-1/#comment-517 tanelp Fri, 15 Aug 2008 09:00:59 +0000 http://tanelpoder.wordpress.com/2008/08/15/why-does-even-a-small-difference-in-sql-text-cause-a-hard-parse/#comment-517 Sokrates, check this example: <code> SQL> alter system flush shared_pool; System altered. SQL> select sql_text from v$sql where lower(sql_text) like 'select%dual'; no rows selected SQL> declare i number; begin select /* blah */ CoUnT( * ) into i FROM DuAl; end; 2 / PL/SQL procedure successfully completed. SQL> select sql_text from v$sql where lower(sql_text) like 'select%dual'; SQL_TEXT --------------------------------------------------------------------------------------- SELECT COUNT( * ) FROM DUAL SQL> </code> Sokrates, check this example:

SQL> alter system flush shared_pool;

System altered.

SQL> select sql_text from v$sql where lower(sql_text) like 'select%dual';

no rows selected

SQL> declare i number; begin select /* blah */ CoUnT( * ) into i FROM DuAl; end;
2 /

PL/SQL procedure successfully completed.

SQL> select sql_text from v$sql where lower(sql_text) like 'select%dual';

SQL_TEXT
---------------------------------------------------------------------------------------
SELECT COUNT( * ) FROM DUAL

SQL>

]]> By: Sokrates http://blog.tanelpoder.com/2008/08/15/why-does-even-a-small-difference-in-sql-text-cause-a-hard-parse/comment-page-1/#comment-516 Sokrates Fri, 15 Aug 2008 08:33:32 +0000 http://tanelpoder.wordpress.com/2008/08/15/why-does-even-a-small-difference-in-sql-text-cause-a-hard-parse/#comment-516 very interesting, thank you. So please, could you point out a bit further, when does PL/SQL try to generate "canonical SQL" ? very interesting, thank you.
So please, could you point out a bit further, when does PL/SQL try to generate “canonical SQL” ?

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