Re: Indexing columns with low cardinality: persistent bitmap indexes?

On Mon, Jan 12, 2009 at 1:38 PM, Bruno Lavoie <bruno(dot)lavoie(at)gmail(dot)com> wrote:
> Hello,
>
> I have a column with a small number of distinct values, indexing this one
> with a standard BTree is useless. How do I can index this column
> efficiently? I searched and it seems that pg doesn't support the creation of
> persistent bitmap indexes... Is that feature planned in next releases of pg?

You have a few options based on your access patterns. If you tend to
access just one of these an get them all at once, then either clusting
on this value, or partitioning your table will help.

If you access your data using these values and other column values at
the same time, then partial or multi-column indexes might help.