"Mark Cave-Ayland" <m.cave-ayland@webbased.co.uk> writes:
> This sounds exactly as if it would solve the problem. Have you got any
> pointers to documentation on this, and more specifically on the
> PostgreSQL implementation of GiST? (I'm guessing this is a GiST only
> extension). Has it been available since PostgreSQL 7.1 aswell?
No, lossiness is a generic index property. There's been some level of
support for it since Berkeley days, although we improved the flexibility
in 7.2 --- we now think of lossiness as a property associated with
specific operators rather than a whole index. That would probably not
matter for this particular situation, since you'd be wanting to mark all
the operators lossy anyway.
You can read about this stuff in the PG Programmer's Guide,
"Interfacing Extensions To Indexes". I'd start with the 7.3 version
and then work backwards.
regards, tom lane