Re: Gin index on array of uuid

On Wed, Jun 29, 2016 at 6:17 AM, M Enrique <enrique.mailing.lists@gmail.com> wrote:

What's a good source code entry point to review how this is working for anyarray currently? I am new to the postgres code. I spend some time looking for it but all I found is the following (which I have not been able to decipher yet).

Look on https://commitfest.postgresql.org/4/145/

 

Thank you,

Enrique

On Tue, Jun 21, 2016 at 12:20 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:

Enrique MailingLists <enrique.mailing.lists@gmail.com> writes:
> Currently creating an index on an array of UUID involves defining an
> operator class. I was wondering if this would be a valid request to add as
> part of the uuid-ossp extension? This seems like a reasonable operator to
> support as a default for UUIDs.

This makes me itch, really, because if we do this then we should logically
do it for every other add-on type.

It seems like we are not that far from being able to have just one GIN
opclass on "anyarray".  The only parts of this declaration that are
UUID-specific are the comparator function and the storage type, both of
which could be gotten without that much trouble, one would think.

> Any downsides to adding this as a default?

Well, it'd likely break things at dump/reload time for people who had
already created a competing "default for _uuid" opclass manually.  I'm not
entirely sure, but possibly replacing the core opclasses with a single one
that is "default for anyarray" could avoid such failures.  We'd have to
figure out ambiguity resolution rules.

                        regards, tom lane