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help / color / mirror / Atom feedFrom: Alvaro Herrera <[email protected]>
To: Kouber Saparev <[email protected]>
Cc: [email protected]
Subject: Re: DELETE takes too much memory
Date: Mon, 4 Jul 2016 13:04:58 -0400
Message-ID: <[email protected]> (raw)
In-Reply-To: <CAN4RuQtCYxQg0u_NUncLAyLE-Yd9Yv1Ont5R2skJ53Xygvc4Xg@mail.gmail.com>
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Kouber Saparev wrote:
> I tried to DELETE about 7 million rows at once, and the query went up to
> 15% of the RAM (120 GB in total), which pushed some indexes out and the
> server load went up to 250, so I had to kill the query.
>
> The involved table does not have neither foreign keys referring to other
> tables, nor other tables refer to it. The size of the table itself is 19 GB
> (15% of 120 GB). So why the DELETE tried to put the entire table in memory,
> or what did it do to take so much memory?
Are there triggers in the table? Deferred triggers in particular can
use memory.
--
Álvaro Herrera http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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