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 :)
