[Dxspider-support] how to stop a ??loop??

[Dirk Koopman]

Dave Edwards wrote:
> Hi
> 
> here is a sample of what the debug file is filling up with
> 
> 1194769749^-> D IW0FFK PC92^W4NJA-1^25517^D^5W4NJA-1^5K8SMC^H34^
> 1194769749^<- I DB0SUE-7 PC92^K8SMC^25580^D^5K8SMC^5W4NJA-1^H27^
> 

This problem, a rather subtle one, is caused when there is a circular 
reference deleting mutually connecting nodes as in the examples above. 
It isn't very common, but it causes loops that seems to have happened at 
least twice for long enough for people to notice.

It may also be an artifact of different ways of dealing with deleting 
nodes between DXSpider and any other software that is implementing the 
protocol.

I was auto-vivifying on getting a second D record for a node (after the 
first one had deleted the routing table entry). This meant that the 
lastid had been lost, hence I started from scratch every other D record 
so no deduping. The cure is to ignore PC92 D records for nodes that we 
have not had any other PC92 records for. Perhaps other authors could do 
something similar?

The more people that upgrade from CVS, the smaller (and less likely) the 
loops will be if it happens again...

Dirk