Обсуждение: BUG #17147: Why concat_ws and concat is not immutable?

The following bug has been logged on the website:

Bug reference:      17147
Logged by:          RekGRpth
Email address:      rekgrpth@gmail.com
PostgreSQL version: 13.4
Operating system:   docker alpine
Description:

Why concat_ws and concat is not immutable? And why they cannot be used in
generated always as?

PG Bug reporting form <noreply@postgresql.org> writes:
> Why concat_ws and concat is not immutable?

Those invoke datatype-specific output functions, which aren't guaranteed
to be immutable.  Maybe ideally they would be, but we have too much
historical baggage --- for example, timestamp_out has always depended
on DateStyle.

            regards, tom lane

Thank you for the clarification.

пн, 16 авг. 2021 г. в 19:22, Tom Lane <tgl@sss.pgh.pa.us>:
>
> PG Bug reporting form <noreply@postgresql.org> writes:
> > Why concat_ws and concat is not immutable?
>
> Those invoke datatype-specific output functions, which aren't guaranteed
> to be immutable.  Maybe ideally they would be, but we have too much
> historical baggage --- for example, timestamp_out has always depended
> on DateStyle.
>
>                         regards, tom lane