Here is my output. Note that my updates are for "0.44444444444444442" not
"0.4444444444444444". Both Python 2.5.2 and 2.6.5 interpret the test_value
this way. I wonder if you are not seeing the error due to the float changes
in Python 2.7?
$ uname -a
Linux dev05 2.6.24-24-server #1 SMP Wed Apr 15 15:41:09 UTC 2009 x86_64
GNU/Linux
$ python
Python 2.5.2 (r252:60911, Jan 20 2010, 23:14:04)
[GCC 4.2.4 (Ubuntu 4.2.4-1ubuntu3)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import sqlalchemy
>>> sqlalchemy.__version__
'0.6.5'
>>> 0.4444444444444444444
0.44444444444444442
>>>
$ python ~/float_update_test.py
2010-11-05 06:12:13,122 INFO sqlalchemy.engine.base.Engine.0x...b750 SELECT
DATABASE()
2010-11-05 06:12:13,122 INFO sqlalchemy.engine.base.Engine.0x...b750 ()
2010-11-05 06:12:13,124 INFO sqlalchemy.engine.base.Engine.0x...b750 SHOW
VARIABLES LIKE 'character_set%%'
2010-11-05 06:12:13,124 INFO sqlalchemy.engine.base.Engine.0x...b750 ()
2010-11-05 06:12:13,125 INFO sqlalchemy.engine.base.Engine.0x...b750 SHOW
VARIABLES LIKE 'lower_case_table_names'
2010-11-05 06:12:13,125 INFO sqlalchemy.engine.base.Engine.0x...b750 ()
2010-11-05 06:12:13,126 INFO sqlalchemy.engine.base.Engine.0x...b750 SHOW
COLLATION
2010-11-05 06:12:13,126 INFO sqlalchemy.engine.base.Engine.0x...b750 ()
2010-11-05 06:12:13,130 INFO sqlalchemy.engine.base.Engine.0x...b750 SHOW
VARIABLES LIKE 'sql_mode'
2010-11-05 06:12:13,130 INFO sqlalchemy.engine.base.Engine.0x...b750 ()
2010-11-05 06:12:13,131 INFO sqlalchemy.engine.base.Engine.0x...b750
CREATE TABLE sqlalchemy_test_my_model (
id INTEGER NOT NULL AUTO_INCREMENT,
float_value FLOAT,
PRIMARY KEY (id)
)ENGINE=InnoDB
2010-11-05 06:12:13,132 INFO sqlalchemy.engine.base.Engine.0x...b750 ()
2010-11-05 06:12:13,135 INFO sqlalchemy.engine.base.Engine.0x...b750 COMMIT
2010-11-05 06:12:13,138 INFO sqlalchemy.engine.base.Engine.0x...b750 BEGIN
(implicit)
2010-11-05 06:12:13,139 INFO sqlalchemy.engine.base.Engine.0x...b750 INSERT
INTO sqlalchemy_test_my_model (float_value) VALUES (%s)
2010-11-05 06:12:13,139 INFO sqlalchemy.engine.base.Engine.0x...b750
(0.44444444444444442,)
2010-11-05 06:12:13,140 INFO sqlalchemy.engine.base.Engine.0x...b750 COMMIT
2010-11-05 06:12:13,143 INFO sqlalchemy.engine.base.Engine.0x...b750 BEGIN
(implicit)
2010-11-05 06:12:13,144 INFO sqlalchemy.engine.base.Engine.0x...b750 SELECT
sqlalchemy_test_my_model.id AS sqlalchemy_test_my_model_id,
sqlalchemy_test_my_model.float_value AS sqlalchemy_test_my_model_float_value
FROM sqlalchemy_test_my_model
WHERE sqlalchemy_test_my_model.id = %s
2010-11-05 06:12:13,144 INFO sqlalchemy.engine.base.Engine.0x...b750 (1L,)
2010-11-05 06:12:13,146 INFO sqlalchemy.engine.base.Engine.0x...b750 UPDATE
sqlalchemy_test_my_model SET float_value=%s WHERE
sqlalchemy_test_my_model.id = %s
2010-11-05 06:12:13,147 INFO sqlalchemy.engine.base.Engine.0x...b750
(0.44444444444444442, 1L)
2010-11-05 06:12:13,147 INFO sqlalchemy.engine.base.Engine.0x...b750
ROLLBACK
2010-11-05 06:12:13,149 INFO sqlalchemy.engine.base.Engine.0x...b750
DROP TABLE sqlalchemy_test_my_model
2010-11-05 06:12:13,149 INFO sqlalchemy.engine.base.Engine.0x...b750 ()
2010-11-05 06:12:13,425 INFO sqlalchemy.engine.base.Engine.0x...b750 COMMIT
Traceback (most recent call last):
File "/nail/home/lenza/float_update_test.py", line 70, in <module>
test_class.test_update_data()
File "/nail/home/lenza/float_update_test.py", line 51, in test_update_data
session.commit()
File "/var/lib/python-support/python2.5/sqlalchemy/orm/session.py", line
623, in commit
self.transaction.commit()
File "/var/lib/python-support/python2.5/sqlalchemy/orm/session.py", line
385, in commit
self._prepare_impl()
File "/var/lib/python-support/python2.5/sqlalchemy/orm/session.py", line
369, in _prepare_impl
self.session.flush()
File "/var/lib/python-support/python2.5/sqlalchemy/orm/session.py", line
1397, in flush
self._flush(objects)
File "/var/lib/python-support/python2.5/sqlalchemy/orm/session.py", line
1478, in _flush
flush_context.execute()
File "/var/lib/python-support/python2.5/sqlalchemy/orm/unitofwork.py",
line 304, in execute
rec.execute(self)
File "/var/lib/python-support/python2.5/sqlalchemy/orm/unitofwork.py",
line 448, in execute
uow
File "/var/lib/python-support/python2.5/sqlalchemy/orm/mapper.py", line
1852, in _save_obj
(table.description, len(update), rows))
sqlalchemy.orm.exc.StaleDataError: UPDATE statement on table
'sqlalchemy_test_my_model' expected to update 1 row(s); 0 were matched.
On Fri, Nov 5, 2010 at 12:27 AM, Michael Bayer <mike...@zzzcomputing.com>wrote:
>
> On Nov 5, 2010, at 2:51 AM, Lenza McElrath wrote:
>
> Well, turns out that it doesn't take much of a pool at all to get the test
> to fail: http://pastebin.com/trHhiG47
>
>
> sorry, again this works fine, and theres still nothing in the test as given
> that can cause StaleDataError.
>
> output when I add echo=True:
>
> 010-11-05 03:24:49,463 INFO sqlalchemy.engine.base.Engine.0x...e610 SELECT
> DATABASE()
> 2010-11-05 03:24:49,463 INFO sqlalchemy.engine.base.Engine.0x...e610 ()
> 2010-11-05 03:24:49,465 INFO sqlalchemy.engine.base.Engine.0x...e610 SHOW
> VARIABLES LIKE 'character_set%%'
> 2010-11-05 03:24:49,465 INFO sqlalchemy.engine.base.Engine.0x...e610 ()
> 2010-11-05 03:24:49,465 INFO sqlalchemy.engine.base.Engine.0x...e610 SHOW
> VARIABLES LIKE 'lower_case_table_names'
> 2010-11-05 03:24:49,466 INFO sqlalchemy.engine.base.Engine.0x...e610 ()
> 2010-11-05 03:24:49,466 INFO sqlalchemy.engine.base.Engine.0x...e610 SHOW
> COLLATION
> 2010-11-05 03:24:49,466 INFO sqlalchemy.engine.base.Engine.0x...e610 ()
> 2010-11-05 03:24:49,469 INFO sqlalchemy.engine.base.Engine.0x...e610 SHOW
> VARIABLES LIKE 'sql_mode'
> 2010-11-05 03:24:49,469 INFO sqlalchemy.engine.base.Engine.0x...e610 ()
> 2010-11-05 03:24:49,470 INFO sqlalchemy.engine.base.Engine.0x...e610
> CREATE TABLE sqlalchemy_test_my_model (
> id INTEGER NOT NULL AUTO_INCREMENT,
> float_value FLOAT,
> PRIMARY KEY (id)
> )ENGINE=InnoDB
>
>
> 2010-11-05 03:24:49,470 INFO sqlalchemy.engine.base.Engine.0x...e610 ()
> 2010-11-05 03:24:49,473 INFO sqlalchemy.engine.base.Engine.0x...e610 COMMIT
> 2010-11-05 03:24:49,474 INFO sqlalchemy.engine.base.Engine.0x...e610 BEGIN
> (implicit)
> 2010-11-05 03:24:49,475 INFO sqlalchemy.engine.base.Engine.0x...e610 INSERT
> INTO sqlalchemy_test_my_model (float_value) VALUES (%s)
> 2010-11-05 03:24:49,475 INFO sqlalchemy.engine.base.Engine.0x...e610
> (0.4444444444444444,)
> 2010-11-05 03:24:49,476 INFO sqlalchemy.engine.base.Engine.0x...e610 COMMIT
> 2010-11-05 03:24:49,477 INFO sqlalchemy.engine.base.Engine.0x...e610 BEGIN
> (implicit)
> 2010-11-05 03:24:49,477 INFO sqlalchemy.engine.base.Engine.0x...e610 SELECT
> sqlalchemy_test_my_model.id AS sqlalchemy_test_my_model_id,
> sqlalchemy_test_my_model.float_value AS
> sqlalchemy_test_my_model_float_value
> FROM sqlalchemy_test_my_model
> WHERE sqlalchemy_test_my_model.id = %s
> 2010-11-05 03:24:49,477 INFO sqlalchemy.engine.base.Engine.0x...e610 (1L,)
> 2010-11-05 03:24:49,479 INFO sqlalchemy.engine.base.Engine.0x...e610 UPDATE
> sqlalchemy_test_my_model SET float_value=%s WHERE
> sqlalchemy_test_my_model.id = %s
> 2010-11-05 03:24:49,479 INFO sqlalchemy.engine.base.Engine.0x...e610
> (0.4444444444444444, 1L)
> 2010-11-05 03:24:49,479 INFO sqlalchemy.engine.base.Engine.0x...e610 COMMIT
> 2010-11-05 03:24:49,480 INFO sqlalchemy.engine.base.Engine.0x...e610
> DROP TABLE sqlalchemy_test_my_model
> 2010-11-05 03:24:49,480 INFO sqlalchemy.engine.base.Engine.0x...e610 ()
> 2010-11-05 03:24:49,482 INFO sqlalchemy.engine.base.Engine.0x...e610 COMMIT
>
>
>
>
>
> On Thu, Nov 4, 2010 at 10:33 PM, Lenza McElrath <le...@lenza.org> wrote:
>
>> Interesting. When I use your simple engine I do not get the error either,
>> but I definitely get it when using my real configuration. We are using a
>> connection pool. So the construction of the session maker for the test
>> looks like this:
>>
>> e = sqlalchemy.create_engine('mysql://', pool=connections.get_pool())
>> sessionmaker = sqlalchemy.orm.sessionmaker(e)
>>
>> The connection pool is somewhat complex, so I will try to find the
>> simplest possible pool that reproduces the problem. But, do you have ideas
>> based on this? The script only fails when I use a Float type with a
>> test_value that is higher percision than the DB can represent. It works
>> when I use an Integer type, or when test_value is 44 or 0.44.
>>
>> Thanks for your help!
>>
>>
>> On Thu, Nov 4, 2010 at 6:18 PM, Michael Bayer
>> <mike...@zzzcomputing.com>wrote:
>>
>>>
>>> On Nov 4, 2010, at 8:17 PM, Lenza McElrath wrote:
>>>
>>> I am getting a StaleDataError when updating a Float column to the same
>>> value twice in a row. This happens because SQLAlchemy thinks that I am
>>> changing the value, but then the DB reports that no value was changed.
>>>
>>> Test case can be seen here: http://pastebin.com/vxFBAMxm
>>>
>>>
>>> the test fails to note what "sessionmaker" is, if I run it like this:
>>>
>>> e = create_engine('mysql://scott:ti...@localhost/test')
>>> test_class = UpdateFunctionTest(sessionmaker(e))
>>>
>>> the script runs as expected with no errors. StaleDataError only occurs
>>> if you execute() an update() or delete() construct that affects the primary
>>> key or version number of a row in the same transaction as one that also
>>> calls flush() and also targets that row. This test doesn't emit any raw SQL
>>> constructs nor does it modify any primary key attributes or use version ids
>>> so no error occurs. Float columns that aren't primary keys have nothing to
>>> do with StaleDataError.
>>>
>>>
>>>
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>>
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