Re: KNNGIST next step: adjusting indexAM API

On Wed, Dec 1, 2010 at 5:22 AM, Dimitri Fontaine <dimitri(at)2ndquadrant(dot)fr> wrote:
> Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> writes:
>> Lastly, I'm pretty un-thrilled with the way that the KNNGIST patch
>> implements the interface to the opclass-specific hook functions.
>> Seems like it would be cleaner to leave the Consistent function alone
>> and invent a new, separate hook function for processing ORDER BY.
>> Is there a strong reason for having both things done in one call,
>> or was that just done as a byproduct of trying to cram all the data
>> into one ScanKey array?
>
> IIRC, the goal here was to be able to benefit from KNN GiST from
> existing GiST indexes as soon as you restart the server with the new
> code compiled in. I'm not sure it's that important in the context of
> preparing 9.1. It seems that pg_upgrade already has to issue a reindex
> script for GiST indexes.

I don't think Tom was proposing to change the on-disk format, just the API.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company