Date: Wed, 6 Nov 2019 16:59:45 -0600
From: Justin Pryzby <pryzby@telsasoft.com>
To: David Wheeler <dwheeler@dgitsystems.com>, Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-performance@lists.postgresql.org,
	Cameron Redpath <credpath@dgitsystems.com>
Subject: Re: Slow planning, fast execution for particular 3-table query
Message-ID: <20191106225945.GE4999@telsasoft.com>
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On Mon, Nov 04, 2019 at 03:04:45AM +0000, David Wheeler wrote:
> Postgres version 9.5.19
> Each of the tables has between 3-4 indexes, and all the indexes include tid as first parameter.

On Mon, Nov 04, 2019 at 12:00:59AM -0500, Tom Lane wrote:
> If this *is* the cause, v11 and up have a performance improvement that
> you need:

But note that index definition will be prohibited since:

https://www.postgresql.org/docs/9.6/release-9-6.html
|Disallow creation of indexes on system columns, except for OID columns (David Rowley)
|Such indexes were never considered supported, and would very possibly misbehave since the system might change the system-column fields of a tuple without updating indexes. However, previously there were no error checks to prevent them from being created.

Justin