On 2014-07-21 16:51:32 -0700, Peter Geoghegan wrote: > On Mon, Jul 21, 2014 at 4:16 PM, Jonathan S. Katz > <jonathan.k...@excoventures.com> wrote: > > With NULLs being indexable, I was wondering if there was some reason why IS > > NOT DISTINCT FROM could not use the index? > > FWIW this works: > > postgres=# explain analyze select * from orders where orderid in (5, null);
I rather doubt it will. x in (y1, ... yn) is essentially expanded to x = y1 OR x = y2, ... OR x = yn. I.e. the NULL comparison will be done using normal equality comparison and thus not return a row with a NULL orderid. Am I missing something? > I think that it would almost be a Simple Matter of Programming to make > IS NOT DISTINCT FROM indexable. Under the hood, IS DISTINCT FROM isn't > very different to using the equality operator: But yea, it probably wouldn't take very much for that. Greetings, Andres Freund -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
