On Wed, Jun 18, 2014 at 8:51 AM, Heikki Linnakangas <hlinnakan...@vmware.com> wrote: > > I liked Greg's sketch of what the opclass support functions would be. It > doesn't seem significantly more complicated than what's in the patch now.

Which was On Tue, Jun 17, 2014 at 8:48 PM, Greg Stark <st...@mit.edu> wrote: > An aggregate to generate a min/max "bounding box" from several values > A function which takes an "bounding box" and a new value and returns > the new "bounding box" > A function which tests if a value is in a "bounding box" > A function which tests if a "bounding box" overlaps a "bounding box" Which I'd generalize a bit further by renaming "bounding box" with "compressed set", and allow it to be parameterized. So, you have: An aggregate to generate a "compressed set" from several values A function which adds a new value to the "compressed set" and returns the new "compressed set" A function which tests if a value is in a "compressed set" A function which tests if a "compressed set" overlaps another "compressed set" of equal type If you can define different compressed sets, you can use this to generate both min/max indexes as well as bloom filter indexes. Whether we'd want to have both is perhaps questionable, but having the ability to is probably desirable. One problem with such a generalized implementation would be, that I'm not sure in-place modification of the "compressed set" on-disk can be assumed to be safe on all cases. Surely, for strictly-enlarging sets it would, but while min/max and bloom filters both fit the bill, it's not clear that one can assume this for all structures. Adding also a "in-place updateable" bit to the "type" would perhaps inflate the complexity of the patch due to the need to provide both code paths? -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers