[Sqlalchemy-tickets] Issue #3825: Exception during closing sessions if other thread just closed connection in parallel (zzzeek/sqlalchemy)

[ddzialak <iss...@bi...>]

New issue 3825: Exception during closing sessions if other thread just closed connection in parallel
https://bitbucket.org/zzzeek/sqlalchemy/issues/3825/exception-during-closing-sessions-if-other

ddzialak:

I've got system with many threads, in case of shutdown and even got some trouble with joining other thread I want to close all connections and it may happen that I will receive an error:

{code}
    self._session_factory.close_all()
  File "/var/lib/jenkins/shiningpanda/jobs/5156f59f/virtualenvs/d41d8cd9/lib/python3.5/site-packages/sqlalchemy/orm/session.py", line 57, in close_all
    sess.close()
  File "/var/lib/jenkins/shiningpanda/jobs/5156f59f/virtualenvs/d41d8cd9/lib/python3.5/site-packages/sqlalchemy/orm/session.py", line 1125, in close
    self._close_impl(invalidate=False)
  File "/var/lib/jenkins/shiningpanda/jobs/5156f59f/virtualenvs/d41d8cd9/lib/python3.5/site-packages/sqlalchemy/orm/session.py", line 1164, in _close_impl
    transaction.close(invalidate)
  File "/var/lib/jenkins/shiningpanda/jobs/5156f59f/virtualenvs/d41d8cd9/lib/python3.5/site-packages/sqlalchemy/orm/session.py", line 542, in close
    connection.close()
  File "/var/lib/jenkins/shiningpanda/jobs/5156f59f/virtualenvs/d41d8cd9/lib/python3.5/site-packages/sqlalchemy/engine/base.py", line 867, in close
    del self.__connection
_Connection__connection
{code}

The other thread that was ongoing and logged an exception (that seems to be accurate/correct):
{code}
Traceback (most recent call last):
  File "/var/lib/jenkins/shiningpanda/jobs/5156f59f/virtualenvs/d41d8cd9/lib/python3.5/site-packages/sqlalchemy/engine/base.py", line 346, in connection
    return self.__connection
AttributeError: 'Connection' object has no attribute '_Connection__connection'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/var/lib/jenkins/shiningpanda/jobs/5156f59f/virtualenvs/d41d8cd9/lib/python3.5/site-packages/sqlalchemy/pool.py", line 687, in _finalize_fairy
    fairy._reset(pool)
  File "/var/lib/jenkins/shiningpanda/jobs/5156f59f/virtualenvs/d41d8cd9/lib/python3.5/site-packages/sqlalchemy/pool.py", line 827, in _reset
    self._reset_agent.rollback()
  File "/var/lib/jenkins/shiningpanda/jobs/5156f59f/virtualenvs/d41d8cd9/lib/python3.5/site-packages/sqlalchemy/engine/base.py", line 1615, in rollback
    self._do_rollback()
  File "/var/lib/jenkins/shiningpanda/jobs/5156f59f/virtualenvs/d41d8cd9/lib/python3.5/site-packages/sqlalchemy/engine/base.py", line 1653, in _do_rollback
    self.connection._rollback_impl()
  File "/var/lib/jenkins/shiningpanda/jobs/5156f59f/virtualenvs/d41d8cd9/lib/python3.5/site-packages/sqlalchemy/engine/base.py", line 706, in _rollback_impl
    self.connection._reset_agent is self.__transaction:
  File "/var/lib/jenkins/shiningpanda/jobs/5156f59f/virtualenvs/d41d8cd9/lib/python3.5/site-packages/sqlalchemy/engine/base.py", line 351, in connection
    self._handle_dbapi_exception(e, None, None, None, None)
  File "/var/lib/jenkins/shiningpanda/jobs/5156f59f/virtualenvs/d41d8cd9/lib/python3.5/site-packages/sqlalchemy/engine/base.py", line 1396, in _handle_dbapi_exception
    util.reraise(*exc_info)
  File "/var/lib/jenkins/shiningpanda/jobs/5156f59f/virtualenvs/d41d8cd9/lib/python3.5/site-packages/sqlalchemy/util/compat.py", line 186, in reraise
    raise value
  File "/var/lib/jenkins/shiningpanda/jobs/5156f59f/virtualenvs/d41d8cd9/lib/python3.5/site-packages/sqlalchemy/engine/base.py", line 349, in connection
    return self._revalidate_connection()
  File "/var/lib/jenkins/shiningpanda/jobs/5156f59f/virtualenvs/d41d8cd9/lib/python3.5/site-packages/sqlalchemy/engine/base.py", line 429, in _revalidate_connection
    raise exc.ResourceClosedError("This Connection is closed")
sqlalchemy.exc.ResourceClosedError: This Connection is closed
{code}

I think that the first one exception should not happen. Is it possible to guarantee that all connections would be closed?