[omniORB] performance limits of omniNames (COMM_FAILURE)

[Jaromír Talíř]

Hello,

  we are using omniORB as a communication platform in just created
domain registry system for .cz TLD (about 350000 domains, released as
open source on http://fred.nic.cz). Both python and c++ parts are really
good. Many thanks to authors!
  
  But recently we had noticed on our production server (omniorb-4.0.6),
that in high load, omniNames started refuse to answer 'resolve' command
throwing CORBA/COMM_FAILURE. I managed to simulate this situation (hope
it's the same situation) with omniorb-4.1.0 by this simple script:

---- begin of test.sh -----
#!/bin/bash
while /bin/true
do
    nameclt -ior corbaname::localhost resolve Name.Object > /dev/null
done
---- end of test ----
 
when I run:
> for i in `seq 1 300`; do { ./test.sh & }; done

After few minutes it start output:

Caught a TRANSIENT exception when trying to validate the type of the 
NamingContext. Is the naming service running?
Caught a TRANSIENT exception when trying to validate the type of the 
NamingContext. Is the naming service running?
...

And after small time:

Unexpected CORBA COMM_FAILURE exception when trying to narrow the
NamingContext.
Unexpected CORBA COMM_FAILURE exception when trying to narrow the
NamingContext.
Unexpected CORBA COMM_FAILURE exception when trying to narrow the
NamingContext.
Unexpected CORBA COMM_FAILURE exception when trying to narrow the
NamingContext.
...

What should it be? I tried to lookup omniORB thread options and I think
defaults are fine. I expect that when no corba resources (threads?) are
available, call is blocked waiting for resource(clientCallTimeOutPeriod
is 0 by default), so there shouldn't be any failure (and only efficiancy
will drop), is it true?

Regards

Jaromir Talir
CZ.NIC
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