Cory Nelson wrote:
> The phrase you're looking for here is "CIDR block".
Well, I was avoiding the phrase on purpose :-). I was worried that
using another bit of jargon -- one that is even more opaque than
"prefix" to someone unfamiliar with the space -- did not seem likely to
help get the idea across. But since you and this forum probably do not
have a burning interest in the minutiae of my flawed writing process, I
press on.
> The way I'd handle this is something like this:
>
> Expand the prefix into the full feed:beef:0000:etc
>
> Insert into a table (start binary(16), mask_length int)
>
> select top 1 binary,length from table where start <= @input order by
> binary desc
>
> Check if the row is inside the range returned. This will take a single
> index seek.
Um. This looks, wow, much simpler and better than the R*Tree trick.
I guess the only question is whether the binary search into the
(traditional) index will cost more than the R*Tree traversal. In a set
of 10m records we expect to bounce 23 times in a traditional index, if
my math is right. Not sure how that compares to the R*Tree.
I'll see if I can get an apples-to-apples performance comparison
going (and will reply back with the results, in case folks are still
interested).
Thank you!
--
Eric A. Rubin-Smith
I'm just glad it'll be Clark Gable who's falling on his face and
not Gary Cooper.
-- Gary Cooper on his decision not to take the leading role in
"Gone With The Wind."
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