Re: BUG #14177: ARRAYs in VIEWs are inconsistently cast

On Sat, Jun 4, 2016 at 7:17 AM, <taylor(dot)reece(at)zuerchertech(dot)com> wrote:
> The following bug has been logged on the website:
>
> Bug reference: 14177
> Logged by: Taylor Reece
> Email address: taylor(dot)reece(at)zuerchertech(dot)com
> PostgreSQL version: 9.5.3
> Operating system: Ubuntu Server 14.04 and 16.04
> Description:
>
> This is an issue I've noticed throughout 9.3.*, and now in 9.5.*. If I
> define a VIEW ('v1', below), and then use that VIEW's compiled definition to
> create a second VIEW ('v2', below), the two VIEWs have different compiled
> definitions.
>
> I first discovered this inconsistency when I ran pg_dump on a database and
> restored the backup to another server. The servers' schemas were not
> completely consistent with one another, despite running identical versions
> of psql.
>
> I recognize that the differences in VIEW definitions are cosmetic -- they're
> functionally equivalent. One casts an ARRAY of VARCHAR to ::text[] while
> the other casts the elements individually to VARCHAR and then TEXT. In an
> effort to keep database schema completely identical, though, it would be
> nice if a pg_dump into a pg_restore resulted in exactly identical schema.
>
> An example of how to replicate the issue follows. Thank you in advance for
> your expertise, and for such an awesome DB product!
>
> -Taylor
>
> ...
>
> user(at)server:/tmp# psql d1
> psql (9.5.3)
> Type "help" for help.
>
> d1=# CREATE TABLE t (a CHARACTER VARYING);
> CREATE TABLE
> d1=# CREATE VIEW v1 AS SELECT a FROM t WHERE t.a IN ('b','c');
> CREATE VIEW
> d1=# \d+ v1
> View "public.v1"
> Column | Type | Modifiers | Storage | Description
> --------+-------------------+-----------+----------+-------------
> a | character varying | | extended |
> View definition:
> SELECT t.a
> FROM t
> WHERE t.a::text = ANY (ARRAY['b'::character varying, 'c'::character
> varying]::text[]);
>
> d1=# CREATE VIEW v2 AS SELECT t.a
> d1-# FROM t
> d1-# WHERE t.a::text = ANY (ARRAY['b'::character varying, 'c'::character
> varying]::text[]);
> CREATE VIEW
> d1=# \d+ v2
> View "public.v2"
> Column | Type | Modifiers | Storage | Description
> --------+-------------------+-----------+----------+-------------
> a | character varying | | extended |
> View definition:
> SELECT t.a
> FROM t
> WHERE t.a::text = ANY (ARRAY['b'::character varying::text, 'c'::character
> varying::text]);

Patch to fix this behavior was posted (not applied yet though) a
little while ago:

https://www.postgresql.org/message-id/17675.1459353646%40sss.pgh.pa.us

Thanks,
Amit