On 26 February 2017 at 10:09, Sven R. Kunze <srkunze(at)mail(dot)de> wrote:
> >>># create index docs_birthdate_idx ON docs using btree
> (((meta->>'birthdate')::date));
> ERROR: functions in index expression must be marked IMMUTABLE
>
> So, what is the problem here?
>
Date functions are inherently not immutable because of timezones. Your
solution of using to_timestamp doesn't help because it automatically
returns a value in WITH TIMESTAMP. Do you get anywhere by using
"::timestamp without time zone" instead, as suggested here?
https://www.postgresql.org/message-id/4E039D16.20704%40pinpointresearch.com
Geoff