Re: BUG #19473: regression error in dblink: another command is already in progress

On Sat, 9 May 2026 at 00:43, PG Bug reporting form
<noreply(at)postgresql(dot)org> wrote:
>
> The following bug has been logged on the website:
>
> Bug reference: 19473
> Logged by: Oleg Ivanov
> Email address: o15611(at)gmail(dot)com
> PostgreSQL version: 18.3
> Operating system: Linux
> Description:
>
> Testcase:
> SELECT * FROM dblink('dbname=postgres user=postgres', $$ select 7; $$ ) as
> (col1 int);
> SELECT * FROM dblink_connect('connection1', 'host=/var/run/postgresql
> port=5432');
> 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.
>
>
>
>

Hi! Thank you for this report, I was able to reproduce this behaviour.
My git bisect shows that first commit where this errors out is d3c5f37

```
commit d3c5f37dd543498cc7c678815d3921823beec9e9 (HEAD)
Author: Noah Misch <noah(at)leadboat(dot)com>
Date: Mon Jan 8 11:39:56 2024 -0800

Make dblink interruptible, via new libpqsrv APIs.

```

--
Best regards,
Kirill Reshke