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Subject: BUG #19473: regression error in dblink: another command is already in
 progress
To: pgsql-bugs@lists.postgresql.org
From: PG Bug reporting form <noreply@postgresql.org>
Cc: o15611@gmail.com
Reply-To: o15611@gmail.com, pgsql-bugs@lists.postgresql.org
Date: Fri, 08 May 2026 19:29:44 +0000
Message-ID: <19473-92f01422b9220412@postgresql.org>
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 <https://www.postgresql.org/message-id/19473-92f01422b9220412%40postgresql.org>
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The following bug has been logged on the website:

Bug reference:      19473
Logged by:          Oleg Ivanov
Email address:      o15611@gmail.com
PostgreSQL version: 18.3
Operating system:   Linux
Description:       =20

Testcase:
SELECT * FROM dblink('dbname=3Dpostgres user=3Dpostgres', $$ select 7; $$ )=
 as
(col1 int);
SELECT * FROM dblink_connect('connection1', 'host=3D/var/run/postgresql
port=3D5432');
SELECT * FROM dblink_send_query('connection1', $$ select 8 from pg_sleep(1);
$$ );
SELECT dblink_is_busy('connection1');
SELECT * FROM dblink_get_result('connection1') as t(col1 int);
--- SELECT dblink_is_busy('connection1');
SELECT * FROM dblink_exec('connection1', $$ CHECKPOINT; $$);
SELECT * FROM dblink_disconnect('connection1');

 col1
------
    7
(1 row)

 dblink_connect
----------------
 OK
(1 row)

 dblink_send_query
-------------------
                 1
(1 row)

 dblink_is_busy
----------------
              1
(1 row)

 col1
------
    8
(1 row)

ERROR:  another command is already in progress
CONTEXT:  while executing command on dblink connection named "connection1"
 dblink_disconnect
-------------------
 OK
(1 row)

There was no error in 16 version. The error appeared in 17 version. It
seems, there is a regression bug.
The workaround is to uncomment a commented statement.