RE: [ZODB-Dev] In-memory storage with undo ability?
Rooney, Mike (ext. 324) wrote at 2007-1-15 15:49 -0500: ... raise MultipleUndoErrors(failures.items()) MultipleUndoErrors: Undo error 0x15e1: Undo error 0x15e1: _loadBack() failed The actual line in FileStorage.py in _txn_undo_write that is raising the exception is: p, prev, v, snv, ipos = self._transactionalUndoRecord(h.oid, pos, h.tid, h.prev, h.version) The ZODB can only undo changes to an object when there is no later change to this object that should not be undone. That's natural. However, I expect that the ZODB contains some bug that lets the undo fail even when there are no such object changes. I also see occasional invalid back pointer warnings when the index of a FileStorage is rebuild and it may be possible that the two problems are related. -- Dieter ___ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org http://mail.zope.org/mailman/listinfo/zodb-dev
RE: [ZODB-Dev] In-memory storage with undo ability?
If Jim is not right (and DemoStorage does not support undo), then it would not be difficult to derive a RamFileStorage from FileStorage that exactly works like FileStorage but have its file implemented as a StringIO (rather than a file on the file system). Thanks for the clever suggestion! I have implemented a StringIOStorage with apparent success. On another note, a problem appeared however when changing the objects that were persisted and I assumed it to be the fault of my StringIOStorage but when I tried reverting abd using a FileStorage the same error occurred. File C:\Documents and Settings\user\Desktop\smarttree-2.5\database.py, line 25, in commit transaction.commit() File C:\python25\Lib\site-packages\transaction\_manager.py, line 99, in commit return self.get().commit(sub, deprecation_wng=False) File C:\Python25\Lib\site-packages\transaction\_transaction.py, line 407, in commit self._commitResources() File C:\Python25\Lib\site-packages\transaction\_transaction.py, line 506, in _commitResources rm.commit(self) File C:\Python25\Lib\site-packages\transaction\_transaction.py, line 642, in commit self.manager.commit(o, txn) File C:\Python25\Lib\site-packages\ZODB\DB.py, line 747, in commit tid, oids = self._db._storage.undo(self._tid, t) File C:\python25\Lib\site-packages\ZODB\FileStorage\FileStorage.py, line 1117, in undo return self._txn_undo(transaction_id) File C:\python25\Lib\site-packages\ZODB\FileStorage\FileStorage.py, line 1126, in _txn_undo tindex = self._txn_undo_write(tpos) File C:\python25\Lib\site-packages\ZODB\FileStorage\FileStorage.py, line 1205, in _txn_undo_write raise MultipleUndoErrors(failures.items()) MultipleUndoErrors: Undo error 0x15e1: Undo error 0x15e1: _loadBack() failed The actual line in FileStorage.py in _txn_undo_write that is raising the exception is: p, prev, v, snv, ipos = self._transactionalUndoRecord(h.oid, pos, h.tid, h.prev, h.version) Since there is an error for this and the errors are put into a dictionary and such, I assume this is not all that rare to occur. Is there a common reason this happens that anyone might be able to clue me in on? Thanks, Mike ___ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org http://mail.zope.org/mailman/listinfo/zodb-dev
Re: [ZODB-Dev] In-memory storage with undo ability?
Rooney, Mike (ext. 324) wrote at 2007-1-10 17:01 -0500: Hi everyone, I have what I imagine is a pretty simple question. I am looking for a type of storage class (like FileStorage) which allows for undoing but stays in memory instead of on disk. If DemoStorage supported undo it would work but it does not appear to in ZODB 3.6. If Jim is not right (and DemoStorage does not support undo), then it would not be difficult to derive a RamFileStorage from FileStorage that exactly works like FileStorage but have its file implemented as a StringIO (rather than a file on the file system). -- Dieter ___ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org http://mail.zope.org/mailman/listinfo/zodb-dev
Re: [ZODB-Dev] In-memory storage with undo ability?
On Jan 10, 2007, at 5:01 PM, Rooney, Mike (ext. 324) wrote: Hi everyone, I have what I imagine is a pretty simple question. I am looking for a type of storage class (like FileStorage) which allows for undoing but stays in memory instead of on disk. If DemoStorage supported undo it would work but it does not appear to in ZODB 3.6. DemoStorage does (or should) support undo. Jim -- Jim Fulton mailto:[EMAIL PROTECTED]Python Powered! CTO (540) 361-1714 http://www.python.org Zope Corporationhttp://www.zope.com http://www.zope.org ___ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org http://mail.zope.org/mailman/listinfo/zodb-dev
