From: Laurenz Albe <laurenz.albe@cybertec.at>
To: Tobias Gierke <tobias.gierke@code-sourcery.de>
To: Justin Pryzby <pryzby@telsasoft.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Linear slow-down while inserting into a table with an ON INSERT trigger ?
Date: Mon, 19 Jul 2021 07:45:02 +0200
Message-ID: <a1aa5745d309e58dab73c1a1ee10cff1ae52b57c.camel@cybertec.at> (raw)
In-Reply-To: <b5b020e9-ad28-a309-12e6-5f6d01218b86@code-sourcery.de>
References: <62070f97-13e7-df73-bed1-f8e48c12bf2d@code-sourcery.de>
<20210717044026.GA19498@telsasoft.com>
<b5b020e9-ad28-a309-12e6-5f6d01218b86@code-sourcery.de>
On Sun, 2021-07-18 at 09:36 +0200, Tobias Gierke wrote:
> Thank you for the detailed explanation ! Just one more question: I've
> did an experiment and reduced the fillfactor on the table updated by the
> trigger to 50%, hoping the HOT feature would kick in and each
> subsequent INSERT would clean up the "HOT chain" of the previous INSERT
> ... but execution times did not change at all compared to 100%
> fillfactor, why is this ? Does the HOT feature only work if a different
> backend accesses the table concurrently ?
No, but until the transaction is done, the tuples cannot be removed,
no matter if they are HOT or not.
Yours,
Laurenz Albe
--
Cybertec | https://www.cybertec-postgresql.com
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To: pgsql-performance@postgresql.org
Cc: laurenz.albe@cybertec.at, tobias.gierke@code-sourcery.de, pryzby@telsasoft.com
Subject: Re: Linear slow-down while inserting into a table with an ON INSERT trigger ?
In-Reply-To: <a1aa5745d309e58dab73c1a1ee10cff1ae52b57c.camel@cybertec.at>
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