RE: How to match hash_value

From: Bobak, Mark <Mark.Bobak_at_il.proquest.com>
Date: Fri, 9 Feb 2007 16:43:27 -0500
Message-ID: <AA29A27627F842409E1D18FB19CDCF270B39D227@AABO-EXCHANGE02.bos.il.pqe>

Brandon,

It's been a while since I did this, but, if I recall correctly, you don't need to match the SQL exactly.

You've got the original SQL, with a unique hash value, and a bad plan. You've got the modified SQL, with a unique hash value, and a (hopefully) improved plan.

Now, you create outlines for both, and then swap the plans. You shouldn't be concerned that the two plans have different, unique hash values.

See MetaLink Doc ID 132547.1 for more details...

Hope that helps,

-Mark

--

Mark J. Bobak
Senior Oracle Architect
ProQuest Information & Learning

There is nothing so useless as doing efficiently that which shouldn't be done at all. -Peter F. Drucker, 1909-2005

-----Original Message-----

From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Allen, Brandon Sent: Friday, February 09, 2007 3:53 PM
To: oracle-l-freelists
Subject: How to match hash_value

Hi List,  

I'm trying to do the ol' stored outline swap-a-roo trick and I'm trying to mimic the query coming from an application, but can't get it to come out with the exact same hash_value even though I have the exact same query text, with the same case and it appears to have the same white space as you can see below, so why don't they have the same hash_value? Any ideas what I'm missing? I suspect it may be a difference in the white spaces, e.g. I have spaces where the original has a tab, but how can I find out what the white spaces are supposed to be?

Thanks,
Brandon  

SQL> select hash_value, sql_text from v$sql where hash_value in (3486651370,1343167348);

HASH_VALUE

---

SQL_TEXT

---

---

3486651370
SELECT s1.spec_template_id,s1.spec_id,s2.spec_template_id ass_spec_template_id,
 s2.spec_id ass_spec_id,s1.company_id,
s1.project_id,s1.spec_class_type,s2.spec _class_type ass_spec_class_type,sa.ass_type FROM IBS_SPEC s1, IBS_SPEC s2, IBS_ SPEC_ASSIGNMENTS sa WHERE s1.spec_id = sa.spec_id AND s2.spec_id = :1 AND sa.
ass_spec_id = :2

1343167348
SELECT s1.spec_template_id,s1.spec_id,s2.spec_template_id ass_spec_template_id,
 s2.spec_id ass_spec_id,s1.company_id,
s1.project_id,s1.spec_class_type,s2.spec _class_type ass_spec_class_type,sa.ass_type FROM IBS_SPEC s1, IBS_SPEC s2, IBS_ SPEC_ASSIGNMENTS sa WHERE s1.spec_id = sa.spec_id AND s2.spec_id = :1 AND sa.
ass_spec_id = :2

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http://www.freelists.org/webpage/oracle-l Received on Fri Feb 09 2007 - 15:43:27 CST