Re: SQL tuning nightmare - db file sequential reads

On Tue, 04 Jul 2006 10:43:47 -0700, Steve Howard wrote:

> This depends on the data. A MINUS will almost always full scan at
> least one table in the query being "minused". An EXISTS will run once
> for each row returned by the outer query (33,000 times in this case).
> Depending on how much data is in S_ETL_R_IMG_6, it may be better or
> worse. If S_ETL_R_IMG_6 is small, it will be better, if large...
>
> Regards,

Yes, you're right, of course. I should have accentuated this condition. Know thy data should be the first commandment of the developer.

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