Re: Problem with performance using query with unnest after migrating from V9.1 to V9.2 and higher

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От Jim Nasby
Тема Re: Problem with performance using query with unnest after migrating from V9.1 to V9.2 and higher
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Msg-id 283046e4-a37f-d8cb-85dc-52d1286e8ffb@BlueTreble.com
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Ответ на Problem with performance using query with unnest after migrating from V9.1 to V9.2 and higher  ("Knels, Udo" <U.Knels@treubuch-it.de>)
Ответы Re: Problem with performance using query with unnest after migrating from V9.1 to V9.2 and higher  ("Knels, Udo" <U.Knels@treubuch-it.de>)
Re: Problem with performance using query with unnest after migrating from V9.1 to V9.2 and higher  ("Knels, Udo" <U.Knels@treubuch-it.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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