Hi Patrick,
Isn’t it OR expansion (OR condition was rewritten to UNION)?
Best regards,
Nenad
From: oracle-l-bounce@xxxxxxxxxxxxx <oracle-l-bounce@xxxxxxxxxxxxx> On Behalf
Of Patrick Jolliffe
Sent: Montag, 25. Januar 2021 10:40
To: oracle-l <oracle-l@xxxxxxxxxxxxx>
Subject: Query Transformation
Dear List,
On Oracle 19c been looking at a poorly performing plan for a little while now.
I've simplified it somewhat as per the details below.
I've resolved the problem itself by
1) creating an extended statistic for column group GMOBJ, GMSUB (which were
correlated)
2) getting developers to replace the 2 binds :nc1 and :nc2 with a single bind,
as the values are actually the same although the optimizer doesn't know this,
so this limits it's options.
However I've got myself bogged down in trying to understand the transformation
that has taken place, really for intellectual curiosity.
I think it's some variation on "cost based or expansion", but how has it
transformed into a union of 3 different parts?
Any help greatly appreciated
Patrick
SQL> SELECT * FROM TABLE(DBMS_XPLAN.DISPLAY_CURSOR(FORMAT=>'ALLSTATS LAST'));
PLAN_TABLE_OUTPUT
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
SQL_ID 5f67d104uv8ht, child number 0
-------------------------------------
SELECT /*+gather_plan_statistics Y */ null FROM P, C1, C2 WHERE ( (
C1.RZVR01 = :nc1 AND C2.GMOBJ BETWEEN '2201' AND '2299') OR (
C1.RZVR01 = :nc2 AND C2.GMOBJ = '2019' AND C2.GMSUB = 'IDT' ) ) AND
( P.RYPYID = C1.RZPYID AND P.RYGLBA = C2.GMAID )
Plan hash value: 1470685083
---------------------------------------------------------------------------------------------------
| Id | Operation | Name | Starts | E-Rows | A-Rows |
A-Time | Buffers |
---------------------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | | 0
|00:00:00.18 | 89916 |
| 1 | CONCATENATION | | 1 | | 0
|00:00:00.18 | 89916 |
| 2 | NESTED LOOPS | | 1 | 1 | 0
|00:00:00.18 | 89886 |
| 3 | NESTED LOOPS | | 1 | 1 | 89115
|00:00:00.13 | 771 |
| 4 | NESTED LOOPS | | 1 | 1 | 89115
|00:00:00.06 | 745 |
| 5 | INLIST ITERATOR | | 1 | | 3
|00:00:00.01 | 8 |
|* 6 | INDEX RANGE SCAN | C1_I | 2 | 3 | 3
|00:00:00.01 | 8 |
|* 7 | INDEX RANGE SCAN | C21I | 3 | 1 | 89115
|00:00:00.05 | 737 |
|* 8 | INDEX UNIQUE SCAN | P_PK | 89115 | 1 | 89115
|00:00:00.04 | 26 |
|* 9 | TABLE ACCESS BY INDEX ROWID | P | 89115 | 1 | 0
|00:00:00.05 | 89115 |
| 10 | NESTED LOOPS | | 1 | 1 | 0
|00:00:00.01 | 26 |
| 11 | NESTED LOOPS | | 1 | 1 | 3
|00:00:00.01 | 15 |
|* 12 | INDEX RANGE SCAN | C1_I | 1 | 1 | 3
|00:00:00.01 | 4 |
| 13 | TABLE ACCESS BY INDEX ROWID | P | 3 | 1 | 3
|00:00:00.01 | 11 |
|* 14 | INDEX UNIQUE SCAN | P_PK | 3 | 1 | 3
|00:00:00.01 | 8 |
|* 15 | INDEX RANGE SCAN | C21I | 3 | 1 | 0
|00:00:00.01 | 11 |
| 16 | NESTED LOOPS | | 1 | 1 | 0
|00:00:00.01 | 4 |
| 17 | NESTED LOOPS | | 1 | 1 | 0
|00:00:00.01 | 4 |
| 18 | NESTED LOOPS | | 1 | 1 | 0
|00:00:00.01 | 4 |
|* 19 | INDEX RANGE SCAN | C1_I | 1 | 1 | 0
|00:00:00.01 | 4 |
| 20 | TABLE ACCESS BY INDEX ROWID| P | 0 | 1 | 0
|00:00:00.01 | 0 |
|* 21 | INDEX UNIQUE SCAN | P_PK | 0 | 1 | 0
|00:00:00.01 | 0 |
|* 22 | INDEX UNIQUE SCAN | C2_PK | 0 | 1 | 0
|00:00:00.01 | 0 |
|* 23 | TABLE ACCESS BY INDEX ROWID | C2 | 0 | 1 | 0
|00:00:00.01 | 0 |
---------------------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
6 - access(("C1"."RZVR01"=:NC1 OR "C1"."RZVR01"=:NC2))
7 - access("C2"."GMOBJ"=U'2019' AND "C2"."GMSUB"=U'IDT')
filter((("C1"."RZVR01"=:NC1 AND "C2"."GMOBJ">=U'2201' AND
"C2"."GMOBJ"<=U'2299') OR
("C1"."RZVR01"=:NC2 AND "C2"."GMOBJ"=U'2019' AND
"C2"."GMSUB"=U'IDT')))
8 - access("P"."RYPYID"="C1"."RZPYID")
9 - filter("P"."RYGLBA"="C2"."GMAID")
12 - access("C1"."RZVR01"=:NC2)
filter(("C1"."RZVR01"=:NC1 OR "C1"."RZVR01"=:NC2))
14 - access("P"."RYPYID"="C1"."RZPYID")
15 - access("C2"."GMOBJ"=U'2019' AND "C2"."GMSUB"=U'IDT' AND
"P"."RYGLBA"="C2"."GMAID")
filter(("C2"."GMOBJ"<=U'2299' AND "C2"."GMOBJ">=U'2201' AND
(LNNVL("C2"."GMSUB"=U'IDT') OR LNNVL("C2"."GMOBJ"=U'2019'))))
19 - access("C1"."RZVR01"=:NC1)
filter(("C1"."RZVR01"=:NC1 OR "C1"."RZVR01"=:NC2))
21 - access("P"."RYPYID"="C1"."RZPYID")
22 - access("P"."RYGLBA"="C2"."GMAID")
23 - filter(("C2"."GMOBJ"<=U'2299' AND "C2"."GMOBJ"<=U'2299' AND
"C2"."GMOBJ">=U'2201'
AND "C2"."GMOBJ">=U'2201' AND (LNNVL("C1"."RZVR01"=:NC2) OR
LNNVL("C2"."GMOBJ"=U'2019') OR
LNNVL("C2"."GMSUB"=U'IDT')) AND (LNNVL("C2"."GMSUB"=U'IDT') OR
LNNVL("C2"."GMOBJ"=U'2019'))))
____________________________________________________
Please consider the environment before printing this e-mail.
Bitte denken Sie an die Umwelt, bevor Sie dieses E-Mail drucken.
<html xmlns="http://www.w3.org/1999/xhtml";>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<style type="text/css">p { font-family: Arial;font-size:9pt }</style>
</head>
<body>
<p>
<br>Important Notice</br>
<br />
This message is intended only for the individual named. It may contain
confidential or privileged information. If you are not the named addressee you
should in particular not disseminate, distribute, modify or copy this e-mail.
Please notify the sender immediately by e-mail, if you have received this
message by mistake and delete it from your system.<br />
Without prejudice to any contractual agreements between you and us which shall
prevail in any case, we take it as your authorization to correspond with you by
e-mail if you send us messages by e-mail. However, we reserve the right not to
execute orders and instructions transmitted by e-mail at any time and without
further explanation.<br />
E-mail transmission may not be secure or error-free as information could be
intercepted, corrupted, lost, destroyed, arrive late or incomplete. Also
processing of incoming e-mails cannot be guaranteed. All liability of Vontobel
Holding Ltd. and any of its affiliates (hereinafter collectively referred to as
"Vontobel Group") for any damages resulting from e-mail use is excluded. You
are advised that urgent and time sensitive messages should not be sent by
e-mail and if verification is required please request a printed version.</br>
Please note that all e-mail communications to and from the Vontobel Group are
subject to electronic storage and review by Vontobel Group. Unless stated to
the contrary and without prejudice to any contractual agreements between you
and Vontobel Group which shall prevail in any case, e-mail-communication is for
informational purposes only and is not intended as an offer or solicitation for
the purchase or sale of any financial instrument or as an official confirmation
of any transaction.<br />
The legal basis for the processing of your personal data is the legitimate
interest to develop a commercial relationship with you, as well as your consent
to forward you commercial communications. You can exercise, at any time and
under the terms established under current regulation, your rights. If you
prefer not to receive any further communications, please contact your client
relationship manager if you are a client of Vontobel Group or notify the sender.
Please note for an exact reference to the affected group entity the corporate
e-mail signature.
For further information about data privacy at Vontobel Group please consult <a
href="https://www.vontobel.com";>www.vontobel.com</a>.<br />
</p>
</body>
</html>
