On E, 2005-03-21 at 09:55 -0800, Josh Berkus wrote:
> Stacy,
>
> > Luckily they that had the chance to work with a truly fantastic DBA (the
> > author of an Oracle Press performance tuning book even) before they could
> > switch back. He convinced them to make some of their indexes global.
> > Performance dramatically improved (compared with both the unpartitioned
> > schema, and the partitioned-and-locally-indexed schema), and they've since
> > stayed with partitioned tables and a mix of local and global indexes.
>
> Hmmm. Wouldn't Greg's suggestion of a bitmap index which holds information on
> what values are found in what partition also solve this? Without 1/2 of
> the overhead imposed by global indexes?
>
> I can actually see such a bitmap as being universally useful to the
> partitioning concept ... for one, it would resolve the whole "partition on
> {value}" issue.
I once (maybe about a year ago) tried to elaborate using bitmap
index(es) with page granularity as a tool for simultaneous clustering
and lookup for data warehousing using postgres. the main idea was to
determine storage location from AND of all "clustered" bitmap indexes
and corresponding fast and clustered lookups.
This could/should/maybe :) possibly be combined with clustering as well.
--
Hannu Krosing <hannu@tm.ee>
