Re: BUG #16897: gssenc request slow connection

Hi,

The libpq version is 12.2. I've attached two images of the packets
transferred on a connection to my db with gssenc=prefer and
gssenc=disable. The client is 10.64.0.3 and the host is 10.64.0.7.
In the gssenc image packet 3155 is the gssenc request. I don't know what
the NBNS packets are doing but they seem to be the cause of the delay.

Cols: No, Time, Source, Destination, Protocol, Length, Info

Thx,
Richard

On Thu, 25 Feb 2021 at 17:43, Stephen Frost <sfrost(at)snowman(dot)net> wrote:

> Greetings,
>
> * PG Bug reporting form (noreply(at)postgresql(dot)org) wrote:
> > Email address: rich(dot)crampton(at)gmail(dot)com
> > PostgreSQL version: 12.6
> > Operating system: client Windows 10, postgresql server Ubuntu
> > Description:
> >
> > When connecting over a local network from Windows 10 to PostgreSQL server
> > (Linux version 12.6 default install) the gssencmode=prefer in libpq
> > connection causes a big slowdown.
> >
> > With "gssencmode=prefer" connection takes 4 seconds.
> > With "gssencmode=disable" connection as fast as normal.
> >
> > As the prefer option is the default option this causes problems in
> dependent
> > libraries such as psycopg2 for Python. First raised the bug here
> > https://github.com/psycopg/psycopg2/issues/1242 but I think this must
> be a
> > libpq/Postgresql bug since psycopg2 is just passing along the request.
>
> What's the version of the libpq library on the client side..? In
> general, while there's an extra packet back and forth because Kerberos /
> GSSAPI is set up on the client / Windows side, once the server says it
> doesn't support GSSENC, libpq should try a non-GSSENC connection right
> away..
>
> Thanks,
>
> Stephen
>