RE: Ideas to workaround view merge being disabled (Answer)

From: Jesse, Rich <Rich.Jesse_at_qtiworld.com>
Date: Mon, 12 Jan 2004 10:34:35 -0800
Message-ID: <F001.005DC712.20040112103435@fatcity.com>

I see that I never replied to the list for the answer, as given by The Goddess herself. Rachel had me create a view of a view, putting the function in the "outer" view while retaining the fields from the DECODE in the "inner" view. The explain plan still isn't optimal, but now at least the view can be merged correctly and the 1M row table lookups now use an index.

Thanks, Rachel! :)
Rich

Rich Jesse                           System/Database Administrator
rjesse_at_qtiworld.com                  Quad/Tech Inc, Sussex, WI USA

-----Original Message-----
Sent: Thursday, January 08, 2004 11:09 AM To: Multiple recipients of list ORACLE-L

<sigh> stupid KVM hacking my mouse gets me again. Here's the *whole* message:

Hey all,

So, there I am on 8.1.7.4.0 creating some SQL suitable for a view:

SELECT

TS.username, 
TS.reportdate, 
TS.hours AS hours, 

DECODE(TD.description, NULL, SC.DESCRIPTION, TD.DESCRIPTION) AS TASK_DESCRIPTION,
TEAM.teamtype AS TeamType,

TS.productline,
ST.SUBTASKID "DEFECTID",
ST.DESCRIPTION "DEFECT_DESCRIPTION"

FROM

T1 TS,
T2 ST,
T3 TD, 
TEAM , 

T5 SC
WHERE

TS.TASKID = TD.TASKID (+) AND 
TS.TEAMID = TEAM.TEAMID AND 
TS.WORKORDERNO = SC.WORKORDERNO (+) 

AND TS.operation = SC.OPERATIONNO (+)
AND TS.TASKID = ST.TASKID (+); Works great, except when the view is created from this SQL because according to Metalink article 1030221.6, the DECODE function is preventing the view from being merged, causing an FTS on the T5 (SC) table. Of course, this table is near 1M rows and gets caught in an inner NL in the explain plan
(cutting/pasting the explain plan doesn't seem to want to work in Windohs).

The doc says the workaround is to move the DECODE outside the view. This won't work for us as the end-user is <sigh> MS Access. Anyone have an idea other than a RULE hint to get around this?

TIA,
Rich

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Author: Jesse, Rich
  INET: Rich.Jesse_at_qtiworld.com

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Received on Mon Jan 12 2004 - 12:34:35 CST