Horton

Re: ISN extension - wrong volatility level for isn_weak() function

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Daniel Gustafsson <daniel@yesql.se>
Cc: Viktor Holmberg <v@viktorh.net>, pgsql-bugs@lists.postgresql.org
Date: 2025-03-14T14:16:24Z
Lists: pgsql-bugs

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. contrib/isn: Make weak mode a GUC setting, and fix related functions.

  2. Update contrib/seg for new scalarlesel/scalargesel selectivity functions.

Daniel Gustafsson <daniel@yesql.se> writes:
> On 14 Mar 2025, at 12:49, Viktor Holmberg <v@viktorh.net> wrote:
>> The isn_weak function in the isn extension reports the wrong value if you look at it inside a transaction:

> I wonder if this should really be marked VOLATILE instead as it has a side
> effect.

Indeed.  This whole area seems really poorly considered.  The comment
in isn--1.1.sql says

-- isn_weak(boolean) - Sets the weak input mode.
-- This function is intended for testing use only!

despite which it's documented at length in isn.sgml.  On the other
hand, so far as I can find it's tested nowhere, which means none
of the "weak mode" code is getting exercised.

			regards, tom lane