NotImplementedError raised with NullPool when MySQL connection times out

[Former user]

I've observed this on multiple Windows XP systems; I don't know if it affects other platforms. The systems are running Python 2.5.2 and recent versions of MySQL 5.

This test requires letting the MySQL connection timeout. For this test I configured the MySQL server with a short timeout (ie, 60 seconds), but I've observed this problem with the default (8 hour) timeout as well.

import sqlalchemy import sqlalchemy.orm eng = sqlalchemy.create_engine('mysql://root:rootpw@localhost/testdb', poolclass = sqlalchemy.pool.NullPool) Session = sqlalchemy.orm.sessionmaker() Session.configure(bind = eng) s = Session() s.execute("SELECT 1") <sqlalchemy.engine.base.ResultProxy object at 0x0148B5B0>

Now wait for the MySQL connection to time out, then in the same Python/IDLE instance:

s = Session() s.execute("SELECT 1")

Traceback (most recent call last): File "<pyshell#11>", line 1, in <module> s.execute("SELECT 1") File "C:\Python25\Lib\site-packages\sqlalchemy\orm\session.py", line 625, in execute return self.__connection(engine, close_with_result=True).execute(clause, params or {}) File "C:\Python25\Lib\site-packages\sqlalchemy\engine\base.py", line 844, in execute return Connection.executorsc(self, object, multiparams, params) File "C:\Python25\Lib\site-packages\sqlalchemy\engine\base.py", line 854, in _execute_text self.__execute_raw(context) File "C:\Python25\Lib\site-packages\sqlalchemy\engine\base.py", line 916, in __execute_raw self._cursor_execute(context.cursor, context.statement, context.parameters0, context=context) File "C:\Python25\Lib\site-packages\sqlalchemy\engine\base.py", line 960, in _cursor_execute self._handle_dbapi_exception(e, statement, parameters, cursor) File "C:\Python25\Lib\site-packages\sqlalchemy\engine\base.py", line 935, in _handle_dbapi_exception self.engine.dispose() File "C:\Python25\Lib\site-packages\sqlalchemy\engine\base.py", line 1133, in dispose self.pool.dispose() File "C:\Python25\Lib\site-packages\sqlalchemy\pool.py", line 161, in dispose raise NotImplementedError() NotImplementedError

This can't be reproduced with raw connections (from eng.connect()); it requires using Session objects.

This is in sqlalchemy 0.4.6, though I've seen it in earlier versions.

[Former user]

The formatting for the Python code seems to have been trashed. Here it is again:

import sqlalchemy import sqlalchemy.orm eng = sqlalchemy.create_engine('mysql://root:rootpw@localhost/testdb', poolclass = sqlalchemy.pool.NullPool) Session = sqlalchemy.orm.sessionmaker() Session.configure(bind = eng) s = Session() s.execute("SELECT 1")

And then after the timeout:

s = Session() s.execute("SELECT 1")

[Former user]

Trying yet again...

import sqlalchemy[BR] import sqlalchemy.orm[BR] eng = sqlalchemy.create_engine('mysql://root:rootpw@localhost/testdb', poolclass = sqlalchemy.pool.NullPool)[BR] Session = sqlalchemy.orm.sessionmaker()[BR] Session.configure(bind = eng)[BR] s = Session()[BR] s.execute("SELECT 1")

And then after the timeout:

s = Session()[BR] s.execute("SELECT 1")

[Mike Bayer]

im sure it can be reproduced with straight Connections. We have a test suite test/engine/reconnect.py which needs to be generalized to other pool classes besides QueuePool.

[Mike Bayer]

this might just involve making dispose() a no-op on NullPool, pretty trivial.

[Mike Bayer]

the tests haven't been refactored yet but the fix for this issue is in 4a89be0bfd559452372836f912f63de2aff60922 fbcaa34b9edb9c7088e630ab7ed337273e6b6d6e

[Mike Bayer]

Removing milestone: 0.4.xx (automated comment)