[Mulgara-general] Can't connect to remote Mulgara repository using ConnectionFactory

Alex Hall alexhall at revelytix.com
Thu Nov 20 17:26:28 UTC 2008


Paul Gearon wrote:
[snip]
> So RMI can't connect to it at all, huh? What about HTTP? On the
> WIndows box, try to retrieve:
> http://SearchMaster:8080/sparql/?query=select+%24subject+%24predicate+%24object+from+%3Crmi%3A%2F%2FSearchMaster%2Fserver1%23sampledata%3E+where+%7B%24subject+%24predicate+%24object%7D
> 
> While typing this, it occurred to me to ask about your DNS. Is
> SearchMaster resolving to 192.168.1.10 for you? Try changing your
> graph name to:
> rmi://192.168.1.10/server1#sampledata
> 
> You can also try the URL with addresses instead of host names:
> http://192.168.1.10:8080/sparql/?query=select+%24subject+%24predicate+%24object+from+%3Crmi%3A%2F%2F192.168.1.10%2Fserver1%23sampledata%3E+where+%7B%24subject+%24predicate+%24object%7D

This reminds me of another issue I've experienced in the past.  RMI connections
with a Mulgara server tend not to work unless the hostname on the server is
properly set (can be easily verified using the Linux 'hostname' command).  The
hostname needs to be a real hostname (not "localhost") which resolves to the
external interface (not the loopback address).  Otherwise RMI connections from
remote machines won't work; I'm not sure if this is a problem with the
canonicalization of server names that Mulgara does, or is deeper in Java RMI.

Regards,
Alex



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