Date: Tue, 6 Feb 2018 12:18:07 -0600
From: Justin Pryzby <pryzby@telsasoft.com>
To: Rick Otten <rottenwindfish@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>,
	PostgreSQL mailing lists <pgsql-performance@postgresql.org>
Subject: Re: failing to use index on UNION of matviews (Re: postgresql 10.1
 wrong plan in when using partitions bug)
Message-ID: <20180206181807.GC32634@telsasoft.com>
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On Sun, Feb 04, 2018 at 11:04:56AM -0500, Rick Otten wrote:
> On Sun, Feb 4, 2018 at 10:35 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> 
> > Rick Otten <rottenwindfish@gmail.com> writes:
> > > I'm wrestling with a very similar problem too - except instead of
> > official
> > > partitions I have a views on top of a bunch (50+) of unioned materialized
> > > views, each "partition" with 10M - 100M rows.  On 9.6.6 the queries would
> > > use the indexes on each materialized view.  On 10.1, every materialized
> > > view is sequence scanned.

I think it'd be useful to see the plan from explain analyze, on both the
"parent" view and a child, with and without SET enable_seqscan=off,

Justin