Re: [BUG] Excessive memory usage with update on STORED generated columns.

From: Matthias van de Meent <boekewurm+postgres(at)gmail(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: "Anton A(dot) Melnikov" <a(dot)melnikov(at)postgrespro(dot)ru>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>, Peter Eisentraut <peter(at)eisentraut(dot)org>
Subject: Re: [BUG] Excessive memory usage with update on STORED generated columns.
Date: 2026-03-30 18:50:37
Message-ID: CAEze2WhsfFwfjooci5gqpSvq_1ibJHnJZ29c58GbDJWH9nbYkA@mail.gmail.com
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On Mon, 30 Mar 2026 at 20:35, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>
> So I think the correct fix is that there needs to be a separate
> boolean tracking whether this work has been done, akin to
> ExecGetExtraUpdatedCols's use of ri_extraUpdatedCols_valid.

Why would it need a new boolean? ri_extraUpdatedCols_valid tracks
exactly whether we've already gone through ExecInitGenerated(...,
CMD_UPDATE), and in doing so if both ri_extraUpdatedCols,
ri_GeneratedExprsU, and ri_NumGeneratedNeededU are valid or whether
they still need to be populated. Adding a new boolean would therefore
be rather duplicative.

See also the patch of a few hours ago at [0].

Kind regards,

Matthias van de Meent
Databricks (https://www.databricks.com)

[0] https://postgr.es/m/CAEze2Wh%2B_C8LtmiMRb58df%3DA1PrBVmMnYMOfbBUk9c%3Dm99CN%2Bw%40mail.gmail.com

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