Re: [NOVICE] array_agg cast issue

Peter Neave <Peter.Neave@jims.net> writes:
> We moved our development database from Windows (PostgreSQL 9.0.1, compiled by Visual C++ build 1500, 64-bit to) to
Linux(PostgreSQL 9.6.1 on x86_64-pc-linux-gnu, compiled by gcc (Debian 4.9.2-10) 4.9.2, 64-bit). When using pgAdmin 4
(v1.4)and DataGrip I get an occasional error message as I’m clicking on table names. 

> For example
>   ERROR: function array_agg(bigint) is not unique
>     Hint: Could not choose a best candidate function. You might need to add explicit type casts.

[ squint... ]  That should not be possible unless something's mucked up
the available set of functions.  In a standard 9.6 database, there are
two versions of array_agg:

regression=# \df array_agg
                           List of functions
   Schema   |   Name    | Result data type | Argument data types | Type
------------+-----------+------------------+---------------------+------
 pg_catalog | array_agg | anyarray         | anyarray            | agg
 pg_catalog | array_agg | anyarray         | anynonarray         | agg
(2 rows)

but only one of those could match any given call with a defined argument
type --- certainly a bigint argument couldn't match the first one.

9.0 was different:

regression=# \df array_agg
                           List of functions
   Schema   |   Name    | Result data type | Argument data types | Type
------------+-----------+------------------+---------------------+------
 pg_catalog | array_agg | anyarray         | anyelement          | agg
(1 row)

I'm suspicious that your DB contains some hacked-up definition for
array_agg() that worked with 9.0 but not so well for 9.6.  I don't
know what DataGrip is, maybe it needs an update?

            regards, tom lane