On Tue, 2006-08-01 at 07:55 -0700, Luke Lonergan wrote: > WRT hashing - we use FNV hash which is a very nice, very fast modern hash > algorithm. We would contribute that if we worked on this.
We currently use Bob Jenkins' hash function[1], which is apparently faster than FNV on most architectures except the Pentium IV (because the P4 has slow shifting -- see [2]). I haven't compared their collision rates -- it may be that we could improve matters incrementally by switching to FNV, but the fundamental problems with our hash index implementation lie elsewhere. -Neil [1] http://burtleburtle.net/bob/hash/doobs.html [2] http://www.azillionmonkeys.com/qed/hash.html ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
