[Zope3-Users] Need help with an urgent problem

[Marius Gedminas]

On Wed, Jan 07, 2009 at 01:28:24PM -0000, kevin gill wrote:
> I am having a problem on my live site. The problem is todo with a DataBase
> connector object which ends up in an incorrect state:
> 
> This is the important part of the traceback.
> 
>   File
> "/home/kevin/src/castingzone.tables/castingzone/tables/person/extraaccount_db.py",
> line 460, in IsValidUser
>     result = self.execute('extraaccount.IsValidUser',
> self.IsValidUser.__doc__, **params)
>   File "/home/kevin/src/castingzone.utility/castingzone/utility/db/db.py",
> line 125, in execute
>     return queryForResults(connection, query)
>   File "/home/kevin/src/castingzone.utility/castingzone/utility/db/db.py",
> line 28, in queryForResults
>     cursor.execute(query)
>   File
> "/srv/zope/hosting/castingzone/instance/hacks/psycopgda-1.0-py2.4.egg/psycopgda/adapter.py",
> line 417, in execute
>     return ZopeCursor.execute(self, operation, parameters)
>   File
> "/srv/zope/hosting/castingzone/eggs/zope.rdb-3.4.0-py2.4.egg/zope/rdb/__init__.py",
> line 261, in execute
>     operation, parameters = self._prepareOperation(operation, parameters)
>   File
> "/srv/zope/hosting/castingzone/eggs/zope.rdb-3.4.0-py2.4.egg/zope/rdb/__init__.py",
> line 278, in _prepareOperation
>     encoding = self.connection.getTypeInfo().getEncoding()
>   File
> "/srv/zope/hosting/castingzone/eggs/ZODB3-3.9.0_dev_r77011-py2.4-linux-i686.egg/ZODB/Connection.py",
> line 798, in setstate
>     raise ConnectionStateError(msg)
> ConnectionStateError: Shouldn't load state for 0x1d54 when the connection
> is closed

If I'm not mistaken, this error typically occurs when you try to hold a
reference to a Persistent object across transaction boundaries (e.g. by
storing it in a global).  Don't do that.

Sometimes this happens in unexpected places (e.g. having a schema with
an Object field that has a default value, and an edit form -- the
default value is never explicitly copied, so you may end up with
multiple references to it).  I'm not saying this could be your problem;
I'm just trying to remind you that some globals may be difficult to
notice if you haven't been burned by them before.

> Once the server gets into this state, it seems to repeat often.
>
> The object in question is a database connection object.

Are you talking about the persistent object with oid 0x1d54?

> I have just
> retrieved it via an adapter lookup. It is not stored.
> 
> connection= zope.component.getUtility(IZopeDatabaseAdapter,  
> CONNECTION_NAME, self.context)()
> 
> The database connection is provided by a global utility. The important
> code is as follows:
> 
> def connection_directive(_context, name=CONNECTION_NAME,
>     connection_string='', encoding='latin-1'):
>     """Process a db:Connection zcml directive"""
> 
>     # Don't delay to the end of the configuration process -
>     gAdapter = PsycopgAdapter(connection_string)
>     gAdapter.setEncoding(encoding)
>     gAdapter.connect()
>     provideUtility(gAdapter, IZopeDatabaseAdapter, name)

This looks okay-ish to me (latin-1, yuck, is this the 20th century still?).

> Any help in narrowing down this problem would be greatly appreciated. It
> is making my live system unworkable.

Start a debug console (zopectl debug or bin/debugzope), then take a look
at oid 0x1d54:

  >>> from ZODB.utils import p64
  >>> app.root()._p_jar.get(p64(0x1d54))

The interesting bit of information is the class name of that object.
Then look through the sources trying to determine the lifetime of that
object: where are references to it created?

Marius Gedminas
-- 
I doubt, therefore I might be.
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