RE: Using miss-spelled hint changes explain plan ...

[Caldwell, Robert A]

Title: Using miss-spelled hint changes explain plan ...

If you miss-spell a hint, it is ignored.

 

select /*+ FULL (PERSON) */ full_name from person where emplid = '123456';

Execution Plan
----------------------------------------------------------
   0      SELECT STATEMENT Optimizer=CHOOSE (Cost=56 Card=1 Bytes=25)
   1    0   TABLE ACCESS (FULL) OF 'PERSON' (Cost=56 Card=1 Bytes=25)

 

 

select /*+ FULLOFIT (PERSON) */ full_name from person where emplid = '123456';

Execution Plan
----------------------------------------------------------
   0      SELECT STATEMENT Optimizer=CHOOSE (Cost=2 Card=1 Bytes=25)
   1    0   TABLE ACCESS (BY INDEX ROWID) OF 'PERSON' (Cost=2 Card=1 Bytes=25)

   2    1     INDEX (UNIQUE SCAN) OF 'PK_EMPLID_1' (UNIQUE) (Cost=1 Card=1)

Rob Caldwell
DBA - United Space Alliance
www.unitedspacealliance.com

-----Original Message-----
From: Jamadagni, Rajendra [mailto:[EMAIL PROTECTED]
Sent: Thursday, November 20, 2003 10:20 AM
To: Multiple recipients of list ORACLE-L
Subject: Using miss-spelled hint changes explain plan ...

Okay,

I found this by accident ...

I was trying to get explain plan on a query that involved a in-line-query that selects from financials database. This in-line query was alias'd as "A".  Current cost of query was ~2800.

So, to test for explain plan I added hint

/*+ diving_site(A) */ -- note the spelling mistake here ... the cost of the query changed to 25. I corrected the spelling mistake and make it driving_site, cost went back to ~2900.

Has anyone experienced this before? Our original db is 9202 and financials is on a RBO, 805 db accessed through a db_link.

Raj
--------------------------------------------------------------------------------
Rajendra dot Jamadagni at nospamespn dot com
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