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 <[email protected]> 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 <[email protected]>
> 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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