RE: Interesting query

From: Khedr, Waleed <Waleed.Khedr_at_FMR.COM>
Date: Wed, 27 Jun 2001 12:42:21 -0700
Message-ID: <F001.0033AA4F.20010627114230@fatcity.com>

select count(*) from a_table where a_column = (select cdk(1234567890) from dual);

Regards,

Waleed

-----Original Message-----
Sent: Wednesday, June 27, 2001 3:01 PM
To: Multiple recipients of list ORACLE-L

My users are writing many of their own functions and it is causing performance to suffer
on a few simple queries. For example, I have a query that just selects count(*) from a
table. With the function

select count(*) from a_table where a_column = cdk(1234567890);

It takes 5 minutes

By plugging in the result of the cdk function into the query

select count(*) from a_table where a_column = 0987654321;

It take .18 of a second.

How can I tell the optimizer that the result of the function will be the same every
time so you don't need to call it for every row? I can do this in the app but it would
be cool to know if I can do this on the database side also.

Thanks, Dave

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Author: David Turner
INET: turner_at_tellme.com

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Author: Khedr, Waleed
INET: Waleed.Khedr_at_FMR.COM

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