Re: BUG #19761: btree_gist: "cannot subtract infinite dates" when inserting 'infinity' into a GiST index on date

On Sun, Oct 25, 2026 at 11:51 AM Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
>
> I think we must fix date_dist as well otherwise it may cause
> inconsistent behavior between index scan and sequence scan, see below
> example
>
> CREATE TABLE t (d date);
> CREATE INDEX t_d_idx ON t USING gist (d);
> INSERT INTO t SELECT date '2000-01-01' + i FROM generate_series(1, 500) i;
> INSERT INTO t VALUES ('infinity');
> INSERT INTO t VALUES ('-infinity');
>
> postgres[3265593]=# SELECT d FROM t ORDER BY d <-> '2000-06-01' LIMIT 1;
> d
> ------------
> 2000-06-01
> (1 row)
>
> -- Now test by turning off the index scan
>
> postgres[3265593]=# set enable_indexscan =off;
> postgres[3265593]=# SELECT d FROM t ORDER BY d <-> '2000-06-01' LIMIT 1;
> 2026-10-25 06:15:58.591 UTC [3265593] ERROR: cannot subtract infinite dates
> 2026-10-25 06:15:58.591 UTC [3265593] STATEMENT: SELECT d FROM t
> ORDER BY d <-> '2000-06-01' LIMIT 1;
> ERROR: 22008: cannot subtract infinite dates
> LOCATION: date_mi, date.c:554
>
> --

Thanks for the review, Dilip. I'm attaching the v2 patch which makes
the change in date_dist also.

Regards,
Nitin Motiani
Google