[cups.bugs] [LOW] STR #3574: cups-polld introduces unnecessary delays in first round of polling

[Evan Broder]

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[STR New]

When cups-polld polls a remote server for printers, it avoids sending all
of the discovered printers to the local cupsd at once, supposedly to avoid
overwhelming the local server.

To do this, it will only send "(number_of_remote_queues /
value_of_BrowseInterval) + 1" queues per second.

However, if BrowseInterval is sufficiently large and the CUPS server has
just been started, this causes a long delay while polld slowly feeds all
of the queues to the cupsd.

In our environment, we set BrowseInterval to 600 to avoid unnecessary load
on our central print server. However, this means that the first tiem we
start CUPS, our workstations only discover 1 printer per second.

I haven't seen any obvious issues that look like the local cupsd gets
overloaded if I set BrowseInterval to 1. What exactly is the concern with
overloading the server? Could the code to throttle requests be dropped
these days?

Alternatively, could cups-polld be modified to not throttle discovered
queues the first time it runs?

Link: http://www.cups.org/str.php?L3574
Version:  -feature