:: I think Helen answered your question pretty well, I just had
:: a thought for you though. I agree with Helen that large
:: fields are generally not good candidates for indices.

Yes,but often necessary.

:: this is the case, you could store say an MD5 or SHA hash of
:: the email address field in a separate indexed field. You may
:: want to find an even simpler system, even CRC might be good

Actually that's what we used to do in the old system. I was my hopes that FB
would do this as part of its indexing instead of making us do this on each
field.. Ie index on a CRC which it looks up first, then comppares full text
of any matcing CRS matches.

I guess it does not? Maybe a good thinig to add in the future? I know other
DB's offer this. CRC 32 works well, but now it will impact all of our
lookups. We have a separate business layer so chagnes are isolated, but its
still a big change that I cannot perform right now.