Subject | Re: [Firebird-Architect] Inexact database operations |
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Author | Ann W. Harrison |
Post date | 2005-06-30T18:18:16Z |
Rick Debay wrote:
costs by counting the number of pointer pages (from RDB$PAGES)
multiplying it by the number of data pages per pointer page (fixed for
each page size) multiplying the result by (the size of a page / byte
length of records). It's imprecise, but "good enough".
Regards
Ann
>The optimizer gets an approximate record count for calculating inexact
> The server. The point was that there are solutions to either calculate
> the results in parallel, or cache them.
costs by counting the number of pointer pages (from RDB$PAGES)
multiplying it by the number of data pages per pointer page (fixed for
each page size) multiplying the result by (the size of a page / byte
length of records). It's imprecise, but "good enough".
Regards
Ann