I can't directly address the concerns you've raised, but for my project I have rewritten TM.py to work better within the begin/vote/finish/abort protocol framework. I've also added more documentation. John Randall F. Kern wrote: > I may just be missing something obvious here, but it seems like there is > a hole in ZODB.Transaction.Transaction.commit and Shared.DC.ZRDB.TM.TM, > that can cause external transactions (those that use the TM mixin class, > like psycopg) to be abandoned (never get committed or rolled back). > > Let's say somewhere around line 300 in Transaction.py (the call to > j.commit(o, self)) we get an exception. Furthermore, let's say the TM > derived database object has already been committed (the only effect of > which is to move the DB into the jars mapping, since TM.tpc_begin() and > TM.commit() both do nothing). > > The exception dumps us down to about line 353, where we call > _p_jar.abort() on all the uncommitted objects (note: it's important that > the database connection isn't in this list, because TM.abort() will > rollback the transaction. the way we keep the db out of this list is by > having it appear in objects _before_ the object that failed the commit). > > Next we reach line ~366, where we should "unwind TPC for the jars that > began it". What this means is calling tpc_abort() on each jar from the > objects that were already committed (which includes the database). > However, TM.tpc_abort() does nothing, leaving the external database > transaction open. > > Does this make sense? > > If this makes sense (i.e. seems bad :), does catching tpc_abort() in TM > and calling TM.abort() seem like a valid fix? > > Thanks, > -Randy > > _______________________________________________ > Zope-Dev maillist - [EMAIL PROTECTED] > http://lists.zope.org/mailman/listinfo/zope-dev > ** No cross posts or HTML encoding! ** > (Related lists - > http://lists.zope.org/mailman/listinfo/zope-announce > http://lists.zope.org/mailman/listinfo/zope ) > > >
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IN NO EVENT SHALL DIGITAL CREATIONS OR ITS # CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF # USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND # ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, # OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT # OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF # SUCH DAMAGE. # # # This software consists of contributions made by Digital Creations and # many individuals on behalf of Digital Creations. Specific # attributions are listed in the accompanying credits file. # ############################################################################## """Provide support for linking an external transaction manager with Zope's """ class TM: """Mix-in class that provides transaction management support A sub class should call self._register() whenever it performs any transaction-dependent operations (e.g. sql statements). The sub class will need to override: _begin if necessary _vote to raise an except if necessary _finish to finallize work, _abort to roll-back work """ def _begin(self): """Hook method to begin external transaction. This may be called multiple times,""" pass def _vote(self): """Hook method to vote on success of transaction commit. This will only be called once,""" pass def _finish(self): """Hook method to complete transaction work. This may be called multiple times.""" pass def _abort(self): """Hook method to undo transaction work. This may be called multiple times.""" pass _registered=None class Surrogate: "A ZODB persistent look-alike." def __init__(self, connection): self._p_jar=connection def _register(self): """This method will register a surrogate persistent object with the transaction. This surrogate will include me in the tpc_* two-phase commit process.""" if not self._registered: try: get_transaction().register(TM.Surrogate(self)) self._registered=1 except: import traceback traceback.print_exc() pass def commit(self, *ignored): "We don't need to actually do an storing." pass def tpc_begin(self, *ignored): "Connection method to begin a commit." self._begin() def tpc_vote(self, *ignored): "Connection method to vote on commit success." self._vote() def tpc_finish(self, *ignored): """Connection method to signal commit success. This should *never* fail""" try: self._finish() finally: self._registered=0 def abort(self, *ignored): """Connnection method to signal commit failure. This should *never* fail""" try: self._abort() finally: self._registered=0