BUG #18829: RAISE NOTICE appends 's' to string in PostgreSQL 17.2

PG Bug reporting form <noreply@postgresql.org> writes:

In PostgreSQL 17.2, when using the RAISE NOTICE command with a string
variable, the output incorrectly appends an extra 's' to the string value.

The substitution marker in plpgsql RAISE strings is just "%", not
"%s" as it is in C, so this output is expected. That wasn't the best
design perhaps, but it's impossible to change it now.

This issue does not occur when running the same code in earlier PostgreSQL
versions (e.g., PostgreSQL 16).

You are quite mistaken about that. It's been like this since the
beginning of plpgsql.

regards, tom lane

On 2025-03-02 Su 9:18 AM, PG Bug reporting form wrote:

The following bug has been logged on the website:

Bug reference: 18829
Logged by: Armand
Email address:armandnortjee@gmail.com
PostgreSQL version: 17.2
Operating system: Windows 10
Description:

In PostgreSQL 17.2, when using the RAISE NOTICE command with a string
variable, the output incorrectly appends an extra 's' to the string value.
This issue does not occur when running the same code in earlier PostgreSQL
versions (e.g., PostgreSQL 16).

DO $$
DECLARE
my_var TEXT := 'garth';
BEGIN
RAISE NOTICE '%s is slim', my_var;
END
$$;

Expected Result:
The output should be:
NOTICE: garth is slim

Actual Result:
The output incorrectly shows:
NOTICE: garths is slim

This is not a bug, it's working as documented.

The 's' is there because you told it to be there. The docs say: "Inside
the format string, |%| is replaced by the string representation of the
next optional argument's value."

This is not a printf style format string, as you appear to think it is.

cheers

andrew

--
Andrew Dunstan
EDB:https://www.enterprisedb.com

On Sun, Mar 2, 2025 at 11:09 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:

PG Bug reporting form <noreply@postgresql.org> writes:

In PostgreSQL 17.2, when using the RAISE NOTICE command with a string
variable, the output incorrectly appends an extra 's' to the string value.

The substitution marker in plpgsql RAISE strings is just "%", not
"%s" as it is in C, so this output is expected. That wasn't the best
design perhaps, but it's impossible to change it now.

This issue does not occur when running the same code in earlier PostgreSQL
versions (e.g., PostgreSQL 16).

You are quite mistaken about that. It's been like this since the
beginning of plpgsql.

While Tom is certainly right about this, I have seen the following
plpgsql code style which looks like the behavior the OP is suggesting,
so they could be mis-remembering.

pagila=# DO $$
DECLARE
my_var TEXT := 'garth';
BEGIN
RAISE NOTICE USING message = format('%s is slim', my_var);
END
$$;
NOTICE: garth is slim
DO

Robert Treat
https://xzilla.net