I am reviewing the indexing the fact tables of a data warehouse and it currently has a clustered primary key and quite a few VERY LARGE covering indexes comprising lots of columns.
The selectivity of the columns other than the primary key is very low; mostly close to 0% with a couple around 15 to 20%. From the SQL 2005 documentation it appears pointless to index these columns. It also has boolean columns indexed?
Would it be better to delete these large (Some are over 80GB in size) indexes and replace them with single column indexes on the foreign keys (to the Dimension tables) only?
Or is there some benefit in keeping some of them?
Many thanks in advance
November 6, 2007 1:17 AM
December 2, 2007 11:51 AM