RE: Psql meta-command conninfo+

Hi Pavel!

>The patch v10 build ends with a warning:
>$ make -j --silent
>describe.c:911:1: warning: no previous prototype for ‘listConnectionInformation’ [-Wmissing-prototypes]
>  911 | listConnectionInformation()
      | ^~~~~~~~~~~~~~~~~~~~~~~~~

>About terms.

I resolved this in v11. I had forgotten to put
the 'void' inside the parentheses (describe.h and describe.c).


>postgres@postgres(17.0)=# \x \conninfo+
>Expanded display is on.
>Current Connection Information
>-[ RECORD 1 ]------+---------
>Database           | postgres
>Authenticated User | postgres
>System User        |
>Current User       | postgres
>Session User       | postgres
>Session PID        | 951112
>Server Version     | 17devel
>Server Address     |
>Server Port        | 5401
>Client Address     |
>Client Port        |
>Socket Directory   | /tmp
>Host               |

>It looks like "Session PID" is a new term for the server process identifier.
>How about changing the name to "Backend PID" (from pg_backend_pid) or even PID (from pg_stat_activity)?


You're right, it's better to stick with the proper terms already in use
in PostgreSQL. This ensures that the user doesn't get confused. I've
changed it to "Backend PID".


>On 08.02.2024 17:58, Maiquel Grassi wrote:

> 1.
> +                     if (db == NULL)
> +                             printf(_("You are currently not connected to a database.\n"));
>
> This check is performed for \conninfo, but not for \conninfo+.

1. The connection check for the case of \conninfo+ is handled by "describe.c" itself since it deals with queries. I might be mistaken, but I believe that by using "printQuery()" via "describe.c", this is already ensured, and there is no need to evaluate the connection status.

>I found that \conninfo and \conninfo+ act differently when the connection is broken.
>I used pg_terminate_backend function from another session to terminate an open psql session.
>After that, \conninfo does not see the connection break (surprisingly!), and \conninfo+ returns an error:

>postgres@postgres(17.0)=# \conninfo+
>FATAL:  terminating connection due to administrator command
>server closed the connection unexpectedly
        >This probably means the server terminated abnormally
        >before or while processing the request.
>The connection to the server was lost. Attempting reset: Succeeded.


For this case, I believe it's already resolved, because if you get a
return indicating that the connection was terminated, and indeed it was,
then "describe.c" is handling it correctly. At least that's what
it seems like.

>postgres@postgres(17.0)=# \conninfo
>You are connected to database "postgres" as user "postgres" via socket in "/tmp" at port "5401".


Here it seems like we have an issue to be studied and subsequently resolved.

>Another surprise is that this check: if (db == NULL) did not work in both cases.

I will investigate further and, if necessary, remove it.

Here's v12, in the next version, I'll try to address the above situation.

Thanks a lot!
Maiquel Grassi.