Re: BUG #14715: Constraint exclusion isn't used in function using language sql

Hello,

At Wed, 21 Jun 2017 14:00:56 +0000, cliveevans(at)ntlworld(dot)com wrote in <20170621140056(dot)27883(dot)82221(at)wrigleys(dot)postgresql(dot)org>
> PostgreSQL version: 9.6.3
...
> The same query written using PL/PGSQL will only scan the expected partition
> tables.

The two are different in that the parameters of the PL/PgSQL
function are regarded as constants at the time of planning of the
inner SQL statement, while those of the SQL function are
not. Constraint exclusion is considered while planning so the SQL
function doesn't get benefit of it.

This doesn't seem a bug, but I couldn't find such a description
in the documentation, though. Maybe it should be here.

https://www.postgresql.org/docs/9.6/static/ddl-partitioning.html#DDL-PARTITIONING-CAVEATS

regareds,

--
Kyotaro Horiguchi
NTT Open Source Software Center