From Paula_Stankus@doh.state.fl.us Tue, 24 Jun 2003 12:56:39 -0700 From: Paula_Stankus@doh.state.fl.us Date: Tue, 24 Jun 2003 12:56:39 -0700 Subject: RE: Dimensional Modeling - b-tree vs. bitmapped indexes Message-ID: MIME-Version: 1.0 Content-Type: text/plain Title: RE: Dimensional Modeling - b-tree vs. bitmapped indexes Guys, My understanding is that Oracle's Star Transformation Algorithm does bitmapped merges on the dimensions tables to pull out the FACTS in the FACT table rather efficiently and that you would use bitmapped indexes on your dimensions tables rather than btree.  However, noted a posted on data warehousing listserve which said "Oracle Expert" was strongly recommending b-tree.  I haven't used Oracle Expert very much - I don't trust it as much as the various traces, running queries and testing yourself.  I guess I feel like Oracle Expert would give you rule-of-thumb stuff and have lots of inherent problems in its "recommendations" - like exactly what you feed it.  I don't trust this over the testing and tracing to see what is happening with the CBO myself.  Any opinions?