From: Tom Lane <tgl@sss.pgh.pa.us>
To: Justin Pryzby <pryzby@telsasoft.com>
cc: pgsql-hackers@postgresql.org, Alvaro Herrera <alvherre@2ndquadrant.com>
Subject: Re: \d+ fails on index on partition
In-reply-to: <20180927200020.GJ776@telsasoft.com>
References: <20180927200020.GJ776@telsasoft.com>
Comments: In-reply-to Justin Pryzby <pryzby@telsasoft.com>
	message dated "Thu, 27 Sep 2018 15:00:20 -0500"
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Date: Thu, 27 Sep 2018 16:51:39 -0400
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Justin Pryzby <pryzby@telsasoft.com> writes:
> pg_get_partition_constraintdef() doesn't like being passed a relkind='I',

It'll also fall over if the passed OID isn't a relation at all, which
is also very much not-nice for SQL-exposed inquiry functions.

I'm inclined to fix this by

(1) inventing an lsyscache function to fetch relispartition, which
will have the behavior of returning false for a lookup failure
(which is generally consistent with the behavior of most of the
other lsyscache functions).

(2) replace the if (rel->rd_rel->relispartition) check in
get_partition_qual_relid with a test like if (get_rel_relispartition(relid)),
and don't open the Relation at all unless that succeeds.

			regards, tom lane