[Tilecache] error raise when seeding tiles

[Fredrik Lundh]

> After a while of seeding tiles with the current command:
> C:\Python25\python tilecache_seed.py
> "http://localhost/tilecache/tilecache.cgy?" osl_baselayer 8 9
> "30000,75000,869680,1097720"
>
> the following error message shows up:
> urllib2.URLError: <urlopen error (10055, 'No buffer space available')>

this means that winsock has run out of memory, possibly because it
runs out of TCP socket buffers or port numbers (since closed sockets
are kept for a while, in case new packages arrive).

a quick googling indicates that you may get around this by increasing
the size of the paging file (or setting it to "system managed").  if
that doesn't help, you may have to tweak the TCP parameters (increase
MaxUserPort and/or decrease TCPTimedWaitDelay):

    http://support.microsoft.com/kb/196271/en-us

maybe the seed application could check for this error, and sleep for a
few minutes (TCPTimedWaitDelay is 120 seconds by default) before
retrying the request?

</F>