Slow query when the select list is big

From: "Sterpu Victor" <victor(at)caido(dot)ro>
To: "PostgreSQL General" <pgsql-general(at)postgresql(dot)org>
Subject: Slow query when the select list is big
Date: 2016-05-09 05:57:45
Message-ID: em5be5fad7-2eaa-4422-bceb-0af6da79973e@victor-pc
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I have a big query that takes about 7 seconds to run(time sending the
data to the client is not counted).
Postgres uses 100% of 1 CPU when solving this query. I tried to run the
query on a HDD and on a SSD with no difference. HDD show about 10% usage
while the query runs.

The query has a big "select" list and no "group by" clause. If I delete
all selects except one the query runs in under a second(it doesn't
matter what field remains selected).
It seems that the query is slow because of the long select, can I do
something to make the query faster?

Thank you.

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