On 02/28/2017 07:30 AM, Sven R. Kunze wrote:
On 28.02.2017 15:40, Adrian Klaver wrote:
[explanation of why date casting and to_datetime don't work]
Why is to_date not immutable?
Not sure, but if I where to hazard a guess, from the source code in formatting.c:
https://git.postgresql.org/gitweb/?p=postgresql.git;a=blob;f =src/backend/utils/adt/formatt ing.c;h=e552c8d20b61a082049068 d2f8d776e35fef1179;hb=HEAD
Would the fact that you can have month names in to_date strings make it dependent on current locale?
That would seem to be it.
cache_locale_time() at the top of DCH_to_char which is in the call stack of the shared parsing code for both to_date and to_timestamp.
Supposedly one could provide a version of to_date that accepts a locale in which to interpret names in the input data - or extend the format string with some kind of "{locale=en_US}" syntax to avoid changing the function signature.
David J.
