MIME-Version: 1.0
From: Matthias van de Meent <boekewurm@gmail.com>
Date: Wed, 11 Mar 2026 15:11:36 +0100
Message-ID: 
 <CAEze2Wi0hg46bcvLQrjid6Kvbb+NSR1N5OKbDNfHy2J=JutJ=Q@mail.gmail.com>
Subject: Instability in test/regress/sql/portals.sql
To: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
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Hi,

Internally at Databricks we've seen rare regression failures in the
portals.sql test, where the regression diff looks something like the
one attached in data_attachments_ed2b37649a9393b5.diffs.

It seems like this was caused by synchronized seqscans, which caused
the foo25ns cursor to start its seqscan not at the start of the table,
but instead with an offset into the table. This changed the output,
because that relied on the seqscan starting at the first page of the
table.

To stabilize this test, let's add SET synchronize_seqscans = off, as attached.

Kind regards,

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

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