[omniORB] How to the Naming Service to support many simultaneous connections.

[Duncan Grisby]

On Wednesday 25 April, souchaud wrote:

> When I launched my programm on a cluster and if I use more than ~200
> nodes, my application cannot start and the following error appear :
> 
> ... Failed to resolve NameService ...
> 
> Here is the portion of the code used to resolve the naming service :
> 
>   // Obtain a reference of the name service:
>   COLCOWS_DEBUG(dblTest, "Obtain a reference of the Naming Service");
>   try {
>     obj_ref = orbp->resolve_initial_references("NameService");
>     new_node_servant->_naming_ctxt =
> CosNaming::NamingContext::_narrow(obj_ref);
>   }
>   catch(...) {
>     COLCOWS_ERROR("Failed to resolve NameService");
>   }

Using catch-all clauses is generally a bad idea since it can mask the
reasons behind problems.

In this case, you are probably getting a COMM_FAILURE exception because
omniNames is unable to service new connections. You can try varying the
omniORB parameters about whether to use thread per connection or thread
pool mode. Depending on your platform, you ought to be able to configure
omniNames to support at least 1000 concurrent connections. If you run
omniNames with -ORBtraceLevel 25 -ORBtraceThreadId 1, you will probably
get an idea of why the connections are failing.

The other thing you can do is to reduce the time omniNames will hold
open idle connections by setting the inConScanPeriod to a small number
of seconds, and setting scanGranularity to 1 second rather than the
default 5. That will mean that it closes idle connections sooner, and be
able to reuse file descriptors and threads.

Cheers,

Duncan.

-- 
 -- Duncan Grisby         --
  -- duncan at grisby.org     --
   -- http://www.grisby.org --