Message-ID: <9511d047-1a08-404b-a502-463fa599f152@gmail.com>
Date: Thu, 21 May 2026 17:13:42 -0300
MIME-Version: 1.0
User-Agent: Mozilla Thunderbird
Subject: Re: BUG #19469: Prevent SIGSEGV on FETCH after ALTER TYPE of cursor
 rowtype
To: haogangmao@gmail.com, pgsql-bugs@lists.postgresql.org,
 PG Bug reporting form <noreply@postgresql.org>
References: <19469-e7612f56d0e1ce34@postgresql.org>
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From: Matheus Alcantara <matheusssilv97@gmail.com>
In-Reply-To: <19469-e7612f56d0e1ce34@postgresql.org>
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On 27/04/26 07:53, PG Bug reporting form wrote:
> The following bug has been logged on the website:
> 
> Bug reference:      19469
> Logged by:          HaoGang Mao
> Email address:      haogangmao@gmail.com
> PostgreSQL version: 17.3
> Operating system:   OS: Linux (Docker)
> Description:
> 
> An open cursor can continue returning tuples built with the old physical
> layout of a named composite type. If that type is changed in the same
> transaction (for example ALTER TYPE ... ALTER ATTRIBUTE ... TYPE), a later
> FETCH may format the tuple using updated descriptor and output metadata.
> 
> Minimal Reproduction SQL:
> ```sql
> CREATE TYPE foo AS (a INT, b INT);
> BEGIN;
> DECLARE c CURSOR FOR
>    SELECT (i, power(2, 30))::foo
>    FROM generate_series(1,10) i;
> FETCH c;
> ALTER TYPE foo ALTER ATTRIBUTE b TYPE TEXT;
> FETCH c;
> COMMIT;
> ```

It looks the same as as [1] and [2]

[1] 
https://www.postgresql.org/message-id/19466-dc32827173299fd4%40postgresql.org
[2] 
https://www.postgresql.org/message-id/19382-4c2060ffee72759b%40postgresql.org

--
Matheus Alcantara
EDB: https://www.enterprisedb.com