Re: OLAP CUBE/ROLLUP Operators and GROUP BY grouping sets

"Robert Bedell" <robert@friendlygenius.com> writes:
> I'm curious if anyone has ever looked into adding OLAP functionality (per
> the SQL99 specs) into PostGreSQL.

There was a fairly crude CUBE implementation submitted (and rejected) a
few months ago, but there's not been any work I thought had a chance of
getting committed.  This is an issue of implementation quality rather
than whether we want the feature --- I think the community is interested
in adding any and all features that are in SQL99.

> More specifically I would like to add grouping sets, and the CUBE and ROLLUP
> operators, into postgresql.  Since modifying such the GROUP BY operation
> would necessitate changing the query structure, wouldn't that affect the
> query rewrites and genetic optimizer?

I don't think either the rewriter or GEQO would notice at all.  The
regular optimizer definitely would though.

> These are not simple projects, I know.

Might be a tad ambitious for your first venture into backend hacking...
        regards, tom lane