• Subject: Re: Query Optimizer
  • From: Pete Hall <pbhall@xxxxxxxxxx>
  • Date: Mon, 08 Nov 1999 20:46:36 -0600

At 07:33 11/08/1999 , R Bruce Hoffman wrote:
>Need more info to give you a good answer. You say the that it built a match
>to second of two logicals. Is there a where clause in the select?

The file is on the dependent side of a left outer join.

>Is the
>logical file *IMMED maint?

Yes

>  Does the logical have select/omit?

No

>Are you sure
>the keys are EXACTLY the same, not a different order?

Only a single key field.

>  How much of the file
>is ultimately selected?
Hmmm. I don't know. I'd estimate 60-80%. I was doing some testing on a 
rather complex view, looking for messages that would indicate which indexes 
were needed. What are the implications of selecting a large vs a small 
percentage of the data?
Pete Hall
pbhall@execpc.com
http://www.execpc.com/~pbhall
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