If the table can be clustered on that column, I suspect it'd be a nice case for the grouped index tuples patch http://community.enterprisedb.com/git/ Actually, simply clustering on that column might give major speedups anyway. Vikul Khosla wrote: > Folks, > > We have just migrated from Oracle to PG. > > We have a database that has approx 3 mil rows and one of the columns has > a cardinality > of only 0.1% (3000 unique values). > > We have to issue several queries that use this low cardinality column in > a WHERE clause > as well as see this column participating in JOINS (ouch!). > > A regular B-Tree index has been created on these columns. > > In Oracle, we replaced the B-Tree Indexes with Bitmap indexes and saw > performance go > through the roof. I know Postgres does not have Bitmap indexes, > but is there a reasonable alternative to boost performance in situations > where low cardinality > columns are involved ? > > I dont have the option of changing schemas - so please dont go there :) > > TIA, > VK -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
