Slow query on a one-tuple table

Luís Roberto Weck <[email protected]> Thu, 19 Sep 2019 13:55:46 -0300

Newsgroups	gmane.comp.db.postgresql.performance
Message-ID	<[email protected]>

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>