RE: Query; Forcing Queries to use exsisting Access Paths

On Tue, 5 Jan 1999, Joe Giusto wrote:
> 
> If you figure out which logical should be used, specify that logical in the
> query instead of the physical file.  
> 

Again, 
it simply doesn't work that way. Specifying logicals in the query, even
best ones for the query, won't force query optimizer(QO) to use them. It
will, however, force QO to consider them first, and therefore, that method
will ensure that these logicals are not ignored simply because QO timed
out.  But, QO has a last word and, under certain circumstances, even
logicals with exact key(s) would be phased out because "QO estimated that
creation of temporary index would be cheaper". 

A few tips: 
- Try to have less than 20% of records to be selected or updated.
- Make sure that your host variables have same description like fields.
(packed 5 0 and packed 6 0 are not the same; packed 5 0 and zoned
5 0 are not the same ...)

Vanya Jovic (who is just enjoying -30C)
Canada


> Joe Giusto II
> Patuxent Publishing Company
>  <mailto:jgiusto@patuxent.com> mailto:JGiusto@patuxent.com
> http://www.lifegoeson.com <http://lifegoeson.com> 
> 
> 
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