On Mon, May 7, 2012 at 12:13 PM, Hanno Schlichting <ha...@hannosch.eu>wrote:

> I think you might get better help on one of the Pyramid support channels.
> Your problems all seem to be related to configuring a web server in
> production mode, rather than database issues.

Thanks, I'll check out the Repoze.BFG IRC channel as well.

>From what I can tell you are dealing with hung requests. I'd look at
> either the paster configuration options for anything related to
> timeouts, thread pools, handling of incomplete requests and so on. Or
> use a more production quality web server like Apache (mod_wsgi), Nginx
> (gevent/gunicon) which likely has better default configuration values
> for these things.

The problem from my previous email was indeed hung requests. However, the
stack trace for those looked different:

Thread 140605868680960:
  File "/usr/lib/python2.6/threading.py", line 504, in __bootstrap
  File "/usr/lib/python2.6/threading.py", line 532, in __bootstrap_inner
  File "/usr/lib/python2.6/threading.py", line 484, in run
    self.__target(*self.__args, **self.__kwargs)
  File "/home/tsa/env/lib/python2.6/site-packages/paste/httpserver.py",
line 878, in worker_thread_callback
  File "/home/tsa/env/lib/python2.6/site-packages/paste/httpserver.py",
line 1052, in <lambda>
    lambda: self.process_request_in_thread(request, client_address))
  File "/home/tsa/env/lib/python2.6/site-packages/paste/httpserver.py",
line 1068, in process_request_in_thread
    self.finish_request(request, client_address)
  File "/usr/lib/python2.6/SocketServer.py", line 322, in finish_request
    self.RequestHandlerClass(request, client_address, self)
  File "/usr/lib/python2.6/SocketServer.py", line 617, in __init__
  File "/home/tsa/env/lib/python2.6/site-packages/paste/httpserver.py",
line 442, in handle
  File "/usr/lib/python2.6/BaseHTTPServer.py", line 329, in handle
  File "/home/tsa/env/lib/python2.6/site-packages/paste/httpserver.py",
line 437, in handle_one_request
  File "/home/tsa/env/lib/python2.6/site-packages/paste/httpserver.py",
line 287, in wsgi_execute
line 21, in __call__
    result = self.next_app(environ, start_response)
line 25, in __call__
    return self.next_app(environ, start_response)
"/home/tsa/env/lib/python2.6/site-packages/repoze/retry/__init__.py", line
65, in __call__
    chunk = original_wsgi_input.read(rest)
  File "/home/tsa/env/lib/python2.6/site-packages/paste/httpserver.py",
line 474, in read
    data = self.file.read(length)
  File "/usr/lib/python2.6/socket.py", line 377, in read
    data = self._sock.recv(left)

Note the line it blocks on is "self._sock.recv(left)", well after the
response started.
In the trace I just provided, the block was on opening the DB connection
*at the start of the request*:

*  File "/home/tsa/env/lib/python2.6/site-packages/paste/httpserver.py",
line 287, in wsgi_execute*
*    self.wsgi_start_response)*
line 18, in __call__
    conn = self.db.open()
*  File "/home/tsa/env/lib/python2.6/site-packages/ZODB/DB.py", line 729,
in open*
*    self._a()*
  File "/usr/lib/python2.6/threading.py", line 123, in acquire
    rc = self.__block.acquire(blocking)

Why would the database start blocking on opening a new database connection?
issue does indeed seem to be with ZODB.

- Claudiu
For more information about ZODB, see http://zodb.org/

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