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From: Luís Roberto Weck <luisroberto@siscobra.com.br>
To: pgsql-performance@lists.postgresql.org
Subject: Slow query on a one-tuple table
Date: Thu, 19 Sep 2019 13:55:46 -0300
Message-ID: <774d6080-d6d7-e9e7-7351-9a412c7d5956@siscobra.com.br> (raw)
In-Reply-To: <24571.1568910502@sss.pgh.pa.us>
References: <CA+t6e1kacbVHq69aihEVeBzH_nMY5eK7bZ-UXL_FuUquEgF_gg@mail.gmail.com>
	<24571.1568910502@sss.pgh.pa.us>

Hi!

I have a query that SELECT's only one tuple using a PK 
(https://explain.depesz.com/s/Hskt) <https://explain.depesz.com/s/Hskt;

the field I am selecting are a bigint and a text. Why does it read 1095 
shared buffers read?

If I adda LIMIT 1 clause, the query runs much faster: 
https://explain.depesz.com/s/bSZn

This table has only one tuple anyway, so I can't understand why does it 
takes so long without the LIMIT 1.
<https://explain.depesz.com/s/Hskt;

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