On Sun, 30 Jan 2005 11:07:59 +1100, Neil Conway <[EMAIL PROTECTED]> wrote: > Mike Rylander wrote: > > For on-disk bitmap indexes, yes. I don't see any reason this couldn't > > be done with GiST > > It might be possible to do it with GiST, but GiST is designed for > implementing tree-structured indexes; I don't think it's the right tool > for the job.
For the initial example where the index is implemented as a set of unique keys from the table and a bitmap for each key this would look a unique index, but with an extra datum at at each index node to hold the bitmap for that key. If implemented that way an augmented B-Tree structure would work fine. At least that's how I would imagine an on-disk bitmap index would work. I suppose that would make the index much more efficient for high-cardinality values, no? -- Mike Rylander [EMAIL PROTECTED] GPLS -- PINES Development Database Developer http://open-ils.org ---------------------------(end of broadcast)--------------------------- TIP 9: the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
