On Tue, Feb 28, 2017 at 9:35 AM, Geoff Winkless <pgsqlad...@geoff.dj> wrote:
> On 28 February 2017 at 15:59, Adrian Klaver <adrian.kla...@aklaver.com> > wrote: > >> 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/formatting.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. https://git.postgresql.org/gitweb/?p=postgresql.git;a=blob;f=src/backend/utils/adt/formatting.c;h=e552c8d20b61a082049068d2f8d776e35fef1179;hb=HEAD#l2363 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.
