[cups] Error 1282 when server has more than 200 printers and domain socket is enabled

[Alex Korobkin]

Yes, it queries it in parallel to speed up processing (with the number of
printers being between 200 and 800 it is important).

Is there any hardcoded limit that I can try to increase?
Also, cupsd.conf has MaxClientsPerHost 1000, does it apply to local client
as well?

2015-02-10 6:44 GMT-05:00 Michael Sweet <msweet at apple.com>:

> Alex,
>
> Is the application querying the PPDs in parallel?  1282 == 0x502 ==
> server-error-service-unavailable, which generally means the connect()
> failed, either because you have exceeded the listen backlog or because
> cupsd is throttling you.  It sounds like the former to me (listen backlog
> exceeded...)
>
>
> > On Feb 9, 2015, at 4:13 PM, Alex Korobkin <korobkin+cups at gmail.com>
> wrote:
> >
> > On a server with CUPS 1.7.5 (and patch for STR#4484) there is an local
> app
> > that queries a list of printers, and then reads their PPDs using CUPS
> API.
> >
> > If I add more than 200 printers to it, local app will frequently fail to
> > retrieve a printer PPD or even get a list of printers, getting "1282
> Transport
> > endpoint is not connected" from CUPS. The more printers I add, the more
> > often I will see error 1282. CUPS at the same time is working fine and is
> > able to return the list of printers normally (as tested with lpstat -a
> and
> > Web UI).
> >
> > If I disable domain socket (Listen /var/run/cups/cups.sock) and restart
> > CUPS, the error will be gone. The app would query CUPS just fine all the
> > time, regardless of the number of printers.
> >
> > I don't see anything helpful in debug log, unfortunately.
> >
> > The only suspicious activity is frequent opening/closing of connections
> via
> > local socket:
> >
> > D [03/Feb/2015:05:42:22 +0000] [Client 52] Accepted from localhost
> (Domain)
> > D [03/Feb/2015:05:42:22 +0000] [Client 52] Waiting for request.
> > D [03/Feb/2015:05:42:22 +0000] [Client 52] HTTP_STATE_WAITING Closing on
> EOF
> > D [03/Feb/2015:05:42:22 +0000] [Client 52] Closing connection.
> > D [03/Feb/2015:05:42:22 +0000] [Client 52] Accepted from localhost
> (Domain)
> > D [03/Feb/2015:05:42:22 +0000] [Client 52] Waiting for request.
> > D [03/Feb/2015:05:42:22 +0000] [Client 52] HTTP_STATE_WAITING Closing on
> EOF
> > D [03/Feb/2015:05:42:22 +0000] [Client 52] Closing connection.
> > D [03/Feb/2015:05:42:22 +0000] [Client 52] Accepted from localhost
> (Domain)
> > D [03/Feb/2015:05:42:22 +0000] [Client 52] Waiting for request.
> > D [03/Feb/2015:05:42:22 +0000] [Client 52] HTTP_STATE_WAITING Closing on
> EOF
> > D [03/Feb/2015:05:42:22 +0000] [Client 52] Closing connection.
> >
> > --
> > Alex
> > _______________________________________________
> > cups mailing list
> > cups at cups.org
> > https://www.cups.org/mailman/listinfo/cups
>
> _________________________________________________________
> Michael Sweet, Senior Printing System Engineer, PWG Chair
>
> _______________________________________________
> cups mailing list
> cups at cups.org
> https://www.cups.org/mailman/listinfo/cups
>



-- 
-Alex