RB Smissaert <[EMAIL PROTECTED]>
wrote:
But then if the base of the logarithm doesn't matter then
how is this equation going to help you?
m==N/logN
So, basically it comes down to some experimenting?
Well, it tells you that if m is much smaller than N (say, by two orders
of magnitude or more), it's a pretty safe bet that index will be useful.
If m is close to N (say, within an order of magnitude), it is a pretty
safe bet the index will be unhelpful. In the middle lies an area where
it's more or less a wash.
Most real world problems tend to fall into the two well-defined areas.
If you find your particular problem to fall into the gray area, then
yes, you might want to experiment. But in this case, even if you find
that an index helps, it is unlikely to help by much, so any advantage
may be outweighed by additional space requirements and slowdown on
inserts and updates.
Igor Tandetnik
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