Обсуждение: BUG #16058: show session_user shows a not clear error message

The following bug has been logged on the website:

Bug reference:      16058
Logged by:          Shaoqi Bai
Email address:      sbai@pivotal.io
PostgreSQL version: 9.6.12
Operating system:   Darwin
Description:

Actual
postgres=# show session_user;
ERROR:  syntax error at or near "session_user" at character 6
STATEMENT:  show session_user;
ERROR:  syntax error at or near "session_user"
LINE 1: show session_user;
             ^

Expected
postgres=# show session_user;
ERROR:  unrecognized configuration parameter "session_user"
STATEMENT:  show session_user;

On Tue, Oct 15, 2019 at 08:26:00AM +0000, PG Bug reporting form wrote:
> Actual
> postgres=# show session_user;
> ERROR:  syntax error at or near "session_user" at character 6
> STATEMENT:  show session_user;
> ERROR:  syntax error at or near "session_user"
> LINE 1: show session_user;
>
> Expected
> postgres=# show session_user;
> ERROR:  unrecognized configuration parameter "session_user"
> STATEMENT:  show session_user;

This boils down to how we would need to handle reserved keyword
parsing for the SHOW command, which would cause reduce/reduce
conflicts with bison as it uses var_name (with ColId).  I would not
bother much with that to be honest.
--
Michael