On Wed, Dec 27, 2006 at 10:16:54PM +1100, Gavin Sherry wrote: > On Wed, 27 Dec 2006, Heikki Linnakangas wrote: > > But actually I'm not convinced we need to worry about efficient storage > > of small bitmaps at all. The typical use case for bitmap indexes is > > large tables with small number of distinct values, and the problem > > doesn't really arise in that scenario. Let's keep it simple for now, we > > can enhance it in later releases. > The scenario I'm concerned about is where a sales data base, say, has > 100,000 products. However, only 500 or 1000 products are popular. They > dominate, say >99% of the sales. The other 99,900 products consume a > little bit over 8K each for very little benefit :-(. > This is pretty contrived but it seem real world enough...
Seems like a good candidate for CREATE INDEX WHERE :-) I wonder what would happen if somebody implemented automatic index exclusion conditions after use of an INDEX proved to be in the realm of the worst case scenario? :-) Cheers, mark -- [EMAIL PROTECTED] / [EMAIL PROTECTED] / [EMAIL PROTECTED] __________________________ . . _ ._ . . .__ . . ._. .__ . . . .__ | Neighbourhood Coder |\/| |_| |_| |/ |_ |\/| | |_ | |/ |_ | | | | | | \ | \ |__ . | | .|. |__ |__ | \ |__ | Ottawa, Ontario, Canada One ring to rule them all, one ring to find them, one ring to bring them all and in the darkness bind them... http://mark.mielke.cc/ ---------------------------(end of broadcast)--------------------------- TIP 7: You can help support the PostgreSQL project by donating at http://www.postgresql.org/about/donate