Re: POC, WIP: OR-clause support for indexes

On Mon, Jun 24, 2024 at 1:46 PM Peter Geoghegan <pg@bowt.ie> wrote:
> BTW, did you know MySQL has long supported the latter? It has a <=>
> operator, which is basically a non-standard spelling of IS NOT
> DISTINCT FROM. Importantly, it is indexable, whereas right now
> Postgres doesn't support indexing IS NOT DISTINCT FROM. If you're
> interested in working on this problem within the scope of this patch,
> or some follow-up patch, I can take care of the nbtree side of things.

To be clear, I meant that we could easily support "where mycol = 5 OR
mycol IS NULL" and have nbtree handle that efficiently, by making it a
SAOP internally. Separately, we could also make IS NOT DISTINCT FROM
indexable, though that probably wouldn't need any work in nbtree.

--
Peter Geoghegan