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Re: AW: Query Optimizer selection incorrect access path



fixed

On 05 Nov 2012 23:10, Birgitta Hauser wrote:
It [<ed:> the query] simply uses the access path of the logical
file, but not the logical file itself, i.e. it ignores the
select/omit clause.

That a query could use the AccPth while ignoring the Slt\Omt specifications can be true *only* for a DYNSLT LF. Without a Dynamic Select specification in the DDS, a Keyed Access Path actually includes or omits the rows with the Access Path itself, so there would be no ability for the query to ignore those specifications when implementing with that AccPth. Whether that has any relevance for the OP scenario is unknown by me; unstated by the OP.

<<SNIP>>

As an aside an SQL index has (per default) a page size of 64 K (while
the default page size for a DDS described logical file is 8K), i.e.
performance may be better.

The PagSiz for a keyed DDS PF or LF is calculated based on the size of the key; i.e. there is no one specific default. A parameter kwd was added to the CRTLF and CRTPF to enable specification of the Page Size; the default is *CALC. IIRC a "short" key actually uses a 4K page size, and smaller page sizes can be better for non-query [RLA] activity and effects on journal; i.e. for effective memory footprint.






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