Re: Getting fancy errors when accessing information_schema on 10.5

Laurenz Albe <laurenz.albe@cybertec.at>

From: Laurenz Albe <laurenz.albe@cybertec.at>
To: Axel Rau <Axel.Rau@Chaos1.DE>, Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-admin@postgresql.org
Date: 2018-10-30T14:40:34Z
Lists: pgsql-hackers
Axel Rau wrote:
> nextcloud=> explain select ((pg_has_role(relowner, 'USAGE'::text) OR has_sequence_privilege(oid, 'SELECT, UPDATE, USAGE'::text))) from pg_class;
>                         QUERY PLAN                         
> -----------------------------------------------------------
>  Seq Scan on pg_class  (cost=0.00..28.56 rows=656 width=1)
> (1 row)
> 
> nextcloud=> explain select (relkind = 'S'::"char") from pg_class;
>                         QUERY PLAN                         
> -----------------------------------------------------------
>  Seq Scan on pg_class  (cost=0.00..28.56 rows=656 width=1)
> (1 row)

Hm, strange, for me the first query is slightly more expensive (because
of the OR), but the costs are pretty similar.

Another idea I have is to raise the costs of "has_sequence_privilege"
slightly.

Yours,
Laurenz Albe