PBS plug-in file handle issue

[oweidner]

After submitting jobs for half a day or so, I see:

Agent submission failed: SAGA Exception (NoSuccess): [saga.plugin.job.pbssh] Couldn't run job because: [Errno 24] Too many open files  
Traceback (most recent call last):
  File "/private/tmp/bliss-vre/lib/python2.6/site-packages/bliss-0.3.0-py2.6.egg/bliss/plugins/pbs/pbsshjob.py", line 253, in job_run
    jobinfo = pbs.submit_job(job)
  File "/private/tmp/bliss-vre/lib/python2.6/site-packages/bliss-0.3.0-py2.6.egg/bliss/plugins/pbs/cmdlinewrapper.py", line 572, in submit_job
    self._check_context()
  File "/private/tmp/bliss-vre/lib/python2.6/site-packages/bliss-0.3.0-py2.6.egg/bliss/plugins/pbs/cmdlinewrapper.py", line 297, in _check_context
    result = cw.run("true")
  File "/private/tmp/bliss-vre/lib/python2.6/site-packages/bliss-0.3.0-py2.6.egg/bliss/utils/command_wrapper.py", line 53, in run
    result = self._ssh_connection.run(cmd)
  File "/private/tmp/bliss-vre/lib/python2.6/site-packages/bliss-0.3.0-py2.6.egg/bliss/utils/openssh_wrapper.py", line 101, in run
    stderr=subprocess.PIPE, env=self.get_env())
  File "/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/subprocess.py", line 588, in __init__
    errread, errwrite) = self._get_handles(stdin, stdout, stderr)
  File "/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/subprocess.py", line 947, in _get_handles
    p2cread, p2cwrite = os.pipe()
OSError: [Errno 24] Too many open files