Hi All
More details on the session issue;
Please note, the test I just did was this;
Restart the mySQL server.
Start Process #1 and create a session and use it (works fine)
Start Process #2 (Identical code to #1, just another instance).
Go back to #1 and attempt to do another query and I get this;
File "Z:\warwickprince On My Mac\Desktop\Code Developement\MSI\Clear
Enterprise\DAP2 Python\trunk\DAPForm.py", line 2556, in _moveToRow
self._formInstance._currentRowProxy = self._query[self._currentPosition]
# Get the one at that position
File "C:\Python26\lib\site-packages\sqlalchemy\orm\query.py", line 1446,
in __getitem__
return list(self[item:item+1])[0]
File "C:\Python26\lib\site-packages\sqlalchemy\orm\query.py", line 1444,
in __getitem__
return list(res)
File "C:\Python26\lib\site-packages\sqlalchemy\orm\query.py", line 1604,
in __iter__
return self._execute_and_instances(context)
File "C:\Python26\lib\site-packages\sqlalchemy\orm\query.py", line 1609,
in _execute_and_instances
mapper=self._mapper_zero_or_none())
File "C:\Python26\lib\site-packages\sqlalchemy\orm\session.py", line 701,
in execute
clause, params or {})
File "C:\Python26\lib\site-packages\sqlalchemy\engine\base.py", line 1194,
in execute
params)
File "C:\Python26\lib\site-packages\sqlalchemy\engine\base.py", line 1272,
in _execute_clauseelement
parameters=params
File "C:\Python26\lib\site-packages\sqlalchemy\engine\base.py", line 1380,
in __create_execution_context
connection=self, **kwargs)
File "C:\Python26\lib\site-packages\sqlalchemy\engine\default.py", line
381, in __init__
self.cursor = self.create_cursor()
File "C:\Python26\lib\site-packages\sqlalchemy\engine\default.py", line
523, in create_cursor
return self._connection.connection.cursor()
File "C:\Python26\lib\site-packages\sqlalchemy\engine\base.py", line 920,
in connection
"Can't reconnect until invalid "
InvalidRequestError: Can't reconnect until invalid transaction is rolled
back
BTW: self._query is self._Session.Query(Product)
I can't quite get my head around the "scope" of sessionmaker() yet.. I've
tried putting Session = sessionmaker() as a global to the entire codebase
(works but has same problem) I've put it inside the process code so that it
can not share any state or memory with the other one(s) (This is the current
config) and yet it's immediately trashing the first session as soon as I
create a second. I'm only *reading* from either of the sessions at this
stage, so there is actually no pending data or writes being done
what-so-ever, so I don't know what transaction should be rolled back or why
it's invalid.
The connection (created in the same myManager class) used for direct
table.select() operations still works fine even after the above error
happens.
Importantly.. I can completely close all my processes and cold start my
code - and this error continues until I restart mySQL ! i.e. NO session
will work again, but I can do basic queries. What the?!
Hope someone can shed some light on this one :-S
BTW: It someone says "You should be using scoped_session.." Please explain
how to have either more than one session in the same context (I use three
for a possible three different binds) or how to create one session that I
can bind to more than one engine, and not have to know in advance all
possible tables I might want to use on each engine.. This is a generic
session that I want to be able to use for all tables in the bound engine -
thus three sessions given that is the maximum possible choices of DB in this
scenario. What if I don't bind a session to any engine.. Does it then
follow the bind on the mapped table class for a given query?
Cheers
Warwick
On 6 October 2010 20:02, Warwick Prince <warwi...@mushroomsys.com> wrote:
> Hi Chris
>
> It's simply trapped as a
>
> except Exception as message:
>
> I'll see what I can do - Just a mo..
>
> Cheers
> Warwick
>
>
> On 6 October 2010 19:54, Chris Withers <ch...@simplistix.co.uk> wrote:
>
>> On 06/10/2010 10:46, Warwick Prince wrote:
>>
>>> (InterfaceError) 2055: Lost connection to MySQL server at
>>> '192.168.50.2:3306 <http://192.168.50.2:3306>', system error: 10054
>>> u'SELECT products......
>>>
>>
>> ...it would be interesting to see the rest of that error message...
>>
>> Chris
>>
>
>
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