> -----Original Message-----
> From: pgsql-hackers-owner@postgresql.org [mailto
gsql-hackers-
> owner@postgresql.org] On Behalf Of Luke Lonergan
> Sent: Friday, July 28, 2006 12:18 PM
> To: Jim C. Nasby; Jie Zhang
> Cc: Tom Lane; Mark Kirkwood; Josh Berkus; Gavin Sherry; pgsql-
> hackers@postgresql.org
> Subject: Re: [HACKERS] On-disk bitmap index patch
>
> Jim,
>
> On 7/28/06 10:17 AM, "Jim C. Nasby" <jnasby@pervasive.com> wrote:
>
> > If the usefulness of bitmap indexes is still in doubt, could someone
at
> > Greenplum provide data from actual data warehouses from actual
> > customers?
>
> First, is anyone in doubt?
Others have looked into the usefulness of bitmap indexes. Here is what
they found:
http://www.oracle.com/technology/pub...a_indexes.html http://citeseer.ist.psu.edu/stockinger02bitmap.html
Oracle, IBM, and even Microsoft[1] supports them. Probably not just to
be trendy.
[1] Microsoft SQL Server creates temporary bitmap indexes during some
queries, though you cannot declaratively create a bitmap index.
> - Luke
>
> ---------------------------(end of
broadcast)---------------------------
> TIP 5: don't forget to increase your free space map settings
---------------------------(end of broadcast)---------------------------
TIP 9: In versions below 8.0, the planner will ignore your desire to
choose an index scan if your joining column's datatypes do not
match