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From: Jim Finnerty <jfinnert@amazon.com>
To: pgsql-performance@postgresql.org
Subject: Re: Query Performance Issue
Date: Sat, 29 Dec 2018 05:00:05 -0700 (MST)
Message-ID: <1546084805706-0.post@n3.nabble.com> (raw)
In-Reply-To: <20181229071535.GX30382@telsasoft.com>
References: <CABFxtPedz4zL+aPWut4+=um4av1aAXr6OVRfRB_6K7mJKMbEcw@mail.gmail.com>
	<20181228153205.GM30382@telsasoft.com>
	<CAKJS1f8933Q2z7dugFcWoWSFAF3deKLMC=98QP_SXT_qPF3J9w@mail.gmail.com>
	<20181229071535.GX30382@telsasoft.com>

Try a pg_hint_plan Rows hint to explore what would happen to the plan if you
fixed the bad join cardinality estimate:

/*+ rows(prm prc #2028) */

alternatively you could specify a HashJoin hint, but I think it's better to
fix the cardinality estimate and then let the optimizer decide what the best
plan is.

I agree with Justin that it looks like the version and
recommended_content_id columns are correlated and that's the likely root
cause of the problem, but you don't need to upgrade to fix this one query.



-----
Jim Finnerty, AWS, Amazon Aurora PostgreSQL
--
Sent from: http://www.postgresql-archive.org/PostgreSQL-performance-f2050081.html




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