Gavin Sherry <[EMAIL PROTECTED]> writes: > On Sun, 23 Jul 2006, Tom Lane wrote: >> However, the main problem I've got with this is that a new index AM is a >> pretty large burden, and no one's made the slightest effort to sell >> pghackers on taking this on.
> For low cardinality sets, bitmaps greatly out perform btree. If the column is sufficiently low cardinality, you might as well just do a seqscan --- you'll be hitting most of the heap's pages anyway. I'm still waiting to be convinced that there's a sweet spot wide enough to justify supporting another index AM. (I'm also wondering whether this doesn't overlap the use-case for GIN.) regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly