John,

This is assuming that if you use the compound index (fld1+fld2) that your where clause will read: WHERE fld1+fld2=x+y. I agree that one bitmap vs. two probably doesn't make much difference.

If you look back in the thread you'll see that I recommended using an index on each field because it's more flexible and I doubt that there will be a perceptible performance difference.

>I don't think this is true. For Rushmore to take effect, you need to match the index expression EXACTLY. In this case, if an index expression is based on the concatenation of two fields, the where or for clause also needs to concatenate the expression. Otherwise, VFP will not be able to find the correct index expression to use.
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>In terms of creating one bitmap versus two, I think this issues is all that relevant. Matching the index expressions and having a deleted tag on the other hand, is....
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>>>You might see a bit better performance from the compound index because VFP creates a bitmap with a bit for each record in the file and a 1 for each record that matches the index and a 0 for each one that doesn't. For two indexes it has to create two bitmaps and then AND them together to figure out which records match.
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