[Sqlalchemy-tickets] [sqlalchemy] #2907: clean out XID state on connection.close()

[sqlalchemy <mi...@zz...>]

#2907: clean out XID state on connection.close()
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 Reporter:  zzzeek  |           Owner:  zzzeek
     Type:  defect  |          Status:  new
 Priority:  high    |       Milestone:  0.9.xx
Component:  engine  |        Severity:  minor - half an hour
 Keywords:          |  Progress State:  in queue
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 On Friday, 10 January 2014 08:06:16 UTC-8, Michael Bayer wrote:
 maybe.   I was thinking, is the Session really doing the right thing here
 by not getting involved, but I think yeah that still might be appropriate.
 so we’d need to carry along some extra information about the transaction
 with the connection so that do_rollback() and do_commit() can pick up on
 that.

 or maybe session.close() needs to do some bookkeeping with the
 SessionTransaction.   not sure.

 The call stack here is:

 -> session.close()
   sqlalchemy/orm/session.py(999)close()
 -> transaction.close()
   sqlalchemy/orm/session.py(437)close()
 -> connection.close()
   sqlalchemy/engine/base.py(583)close()
 -> conn.close()
   sqlalchemy/pool.py(579)close()
 -> self.checkin()
   sqlalchemy/pool.py(506)checkin()
 -> self._pool, None, self._echo, fairy=self)
   sqlalchemy/pool.py(432)_finalize_fairy()
 -> pool._dialect.do_rollback(fairy)

 The tpc state (xid, is_prepared) is held on the TwoPhaseTransaction
 object, referenced (self.__transaction) by the engine Connection object
 which calls conn.close(). I don't think SessionTransaction need be
 involved here, but perhaps the engine Connection / Transaction should.
 Some options are:

 1. In engine Connection.close(), when self.__transaction.is_active pass
 down xid, is_prepared to the _ConnectionFairy. That would imply muddying
 the DBAPI Connection contract of the engine Connection.__connection.

 2. Make the engine Transaction aware of the configured reset_on_return
 behaviour so that Transaction.close() can either rollback or commit.
 Connection.close() could then call Transaction.close().

 3. Keep track of xid, is_prepared on the pool's connection_record.

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Ticket URL: <http://www.sqlalchemy.org/trac/ticket/2907>
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