Subject Re: [Firebird-Architect] Indexes for big objects
Author Ann W. Harrison
Leyne, Sean wrote:
> I don't see the value of this type of index, expect to handle
> uniqueness.
Yes - if you were setting up a list with messages, identifying
messages that are exactly identical lets you detect one kind
of spam. For another, the hash index is very dense compared
to a multi-thousand byte string. There are algorithms for
compressing the trailing characters, but we don't use them, so
a 4,000 byte key that differs in the 3,000th byte will create
an entry thats 1,000 bytes long.