[Zope-DB] Thread question

Dieter Maurer dieter at handshake.de
Thu Jun 24 14:33:40 EDT 2004

Bogdan M. Maryniuck wrote at 2004-6-23 15:26 +0200:
>This is probably wrong maillist, but this is only I can subscribe...

Indeed: "zope at zope.org" would be better...

>I have an object, called "pdfBurner" and I need do in PythonScript 
>something like this:
>context.pdfBurner.burn(filename = 'test.pdf')
>return "PDF burner in process"
>This means, you call this PythonScript and it calls burn() method which
>starts separate thread and *immediately* exits to show use the message
>"PDF burner in process". OK, but it works for me only once. Next time
>it sais:
>File "/opt/Zope-2.6.2/lib/python/ZODB/Connection.py", line 540, in setstate
>    raise RuntimeError(msg)
>RuntimeError: Shouldn't load state for '\x00\x00\x00\x00\x00\x04\xf9\x95' when the connection is closed

This means your thread does not play well with ZODB persistency.

For background, you should read the ZODB3 documentation.

>From it follow the following restrictions:

  *  each thread must use its own ZODB connection

  *  do not forget, to close the connection when it is no longer needed

  *  you must never pass persistent object between threads

     Always locate your objects in the thread itself (e.g.
     given a path)

  *  do not forget to commit/abort the transaction before
     you close the ZODB connection


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