Seth,
> My understanding is that the MPP vendors using PostgreSQL and Ingres are
> not *significantly* altering the software other than to, essentially,
> turn off reliance on indexes. They're then adding extensions that are
> proprietary and not, except in the case of GridSQL, open source. Is my
> understanding correct?
Actually, that's incorrect. Greenplum, Yahoo and Netezza all made
substantial alterations to the PostgreSQL code. Greenplum has
re-written the executor and bulk loader, and seems to be on the way to
re-writing the planner entirely. Yahoo and Netezza each pretty much
ripped out everthing except for the parser and a few other bits (Yahoo
kept the Function code, for example), but replaced a majority of the
PostgreSQL code.
I wouldn't classify GridSQL as MPP. It's strictly PP.
--Josh Berkus
