Re: BUG #17206: the function array_cat(anyarray, anyarray) does not exist

"David G. Johnston" <david.g.johnston@gmail.com> writes:
> On Thu, Sep 30, 2021 at 2:51 PM PG Bug reporting form <
> noreply@postgresql.org> wrote:
>> I get the ERROR : the function array_cat(anyarray, anyarray) does not
>> exist,

> You may find this commit to be illuminating.  Work was done in this area
> for v14.
> https://github.com/postgres/postgres/commit/97f73a978fc1aca59c6ad765548ce0096d95a923

This one might be more so:

https://git.postgresql.org/gitweb/?p=postgresql.git&a=commitdiff&h=9e38c2bb50

Also see the very first item in the v14 compatibility notes:

    User-defined objects that reference certain built-in array functions
    along with their argument types must be recreated (Tom Lane)

    Specifically, array_append(), array_prepend(), array_cat(),
    array_position(), array_positions(), array_remove(), array_replace(),
    and width_bucket() used to take anyarray arguments but now take
    anycompatiblearray. Therefore, user-defined objects like aggregates
    and operators that reference those array function signatures must be
    dropped before upgrading, and recreated once the upgrade completes.

            regards, tom lane