From: Jim Nasby <Jim.Nasby@BlueTreble.com>
To: Knels, Udo <U.Knels@treubuch-it.de>
To: 'pgsql-performance@postgresql.org' <pgsql-performance@postgresql.org>
Subject: Re: Problem with performance using query with unnest after migrating from V9.1 to V9.2 and higher
Date: Wed, 21 Sep 2016 16:48:41 -0500
Message-ID: <283046e4-a37f-d8cb-85dc-52d1286e8ffb@BlueTreble.com> (raw)
In-Reply-To: <1d6ce510f1cf4dfcad73b15ff8ff98a4@EXCH-1.ddd-do.de>
References: <1d6ce510f1cf4dfcad73b15ff8ff98a4@EXCH-1.ddd-do.de>
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On 9/19/16 2:29 AM, Knels, Udo wrote:
> The difference is that V9.1 uses Nested Loop and the index table_a_pk.
> V9.2 and higher don’t use the index.
First thing I'd try is running a manual ANALYZE; on the upgraded
database; the 9.2 plan you showed seems to be using default values, so
it thinks it's going to get 100 rows when it's only getting a few.
--
Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX
Experts in Analytics, Data Architecture and PostgreSQL
Data in Trouble? Get it in Treble! http://BlueTreble.com
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To: pgsql-performance@postgresql.org
Cc: Jim.Nasby@BlueTreble.com, U.Knels@treubuch-it.de
Subject: Re: Problem with performance using query with unnest after migrating from V9.1 to V9.2 and higher
In-Reply-To: <283046e4-a37f-d8cb-85dc-52d1286e8ffb@BlueTreble.com>
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