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From: David G. Johnston <[email protected]>
To: Scott Ribe <[email protected]>
Cc: Pgsql-admin <[email protected]>
Subject: Re: update behavior
Date: Thu, 19 Jun 2025 10:31:59 -0700
Message-ID: <CAKFQuwbwAbbk6KUKXyX2VxpX3aUDhS5Zd__2JKQXdhH5zHaB4g@mail.gmail.com> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>

On Thu, Jun 19, 2025 at 10:24 AM Scott Ribe <[email protected]>
wrote:

> I believe that if I UPDATE a row with the same values that it already has,
> this still dirties pages, writes the row, generates a WAL entry. There is
> no shortcut in the processing that's "hey, there's not really a change
> here, we'll just leave storage alone".
>
> Is this correct?
>
>
Correct.  You need a trigger to prevent the update.  There is one provided:
suppress_redundant_updates_trigger()

https://www.postgresql.org/docs/17/functions-trigger.html

David J.

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