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
