Re: postgres_fdw uninterruptible during connection establishment / ProcSignalBarrier

Hi,

On 2023-01-30 11:30:08 -0800, Nathan Bossart wrote:
> On Mon, Jan 23, 2023 at 07:28:06PM -0800, Andres Freund wrote:
> > After a tiny bit further polishing, and after separately pushing a resource
> > leak fix for walrcv_connect(), I pushed this.
> 
> My colleague Robins Tharakan (CC'd) noticed crashes when testing recent
> commits, and he traced it back to e460248.  From this information, I
> discovered the following typo:
> 
> diff --git a/contrib/dblink/dblink.c b/contrib/dblink/dblink.c
> index 8982d623d3..78a8bcee6e 100644
> --- a/contrib/dblink/dblink.c
> +++ b/contrib/dblink/dblink.c
> @@ -321,7 +321,7 @@ dblink_connect(PG_FUNCTION_ARGS)
>      else
>      {
>          if (pconn->conn)
> -            libpqsrv_disconnect(conn);
> +            libpqsrv_disconnect(pconn->conn);
>          pconn->conn = conn;
>      }

Ugh. Good catch.

Why don't the dblink tests catch this?  Any chance you or Robins could prepare
a patch with fix and test, given that you know how to trigger this?

Greetings,

Andres Freund