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On Feb 11, 2012, at 5:22 AM, Fayaz Yusuf Khan wrote: > The attached script fails with this: > Traceback (most recent call last): > File "stale_delete.py", line 33, in <module> > session.flush() > File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", > line 1559, in flush > self._flush(objects) > File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", > line 1630, in _flush > flush_context.execute() > File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/unitofwork.py", > line 331, in execute > rec.execute(self) > File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/unitofwork.py", > line 498, in execute > uow > File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/mapper.py", line > 2507, in _delete_obj > (table.description, len(del_objects), c.rowcount) > sqlalchemy.orm.exc.StaleDataError: DELETE statement on table 'A' expected to > delete 2 row(s); 1 were matched. > > > in MySQL-InnoDB (works in SQLite and Postgres). > Tried versions 0.7.3 and 0.7.5 > Python 2.7 > > I tried manually deleting the rows from the table through MySQL client and > noticed that it's not returning an accurate row count (doesn't > 'supports_sane_rowcount') for a table with an adjacency relationship and an > ondelete='CASCADE'. > > I'm going to work around this by adding another ondelete='CASCADE' for User->A I ran this and indeed InnoDB appears to be broken here. This is a MySQL bug. It would appear it is running the cascade between the two "A" rows and only considering the lead object to be the one deleted. Can't exactly find it at bugs.mysql.com either, so you'd do everyone a favor if you could create a ticket over there. SQLAlchemy can try to work around this but for now you can just flip supports_sane_rowcount off for the whole dialect: engine.dialect.supports_sane_rowcount = engine.dialect.supports_sane_multi_rowcount = False The only solution I can see is another mapper flag that lets you disable the rowcount check for specific classes (see http://www.sqlalchemy.org/trac/ticket/2403) . Unfortunately I don't see a way to make this very obvious to users not aware of the issue. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (Darwin) Comment: GPGTools - http://gpgtools.org iQEcBAEBAgAGBQJPNon9AAoJEDMCOcHE2v7hVeIH/0HFDYCLUiKH6vuRvEvCapjD XrCwAlpjbu6dCE82YNn00oSvekh0QfFgDgIFafnZzavtE1dn2ve9HvDBviUmmE+h gpMuhVayAZxZfOAYu8512hSb9rx/ZHQv+wt/e4Rl3pnbBGLq1Jg8bufd+S0Ytkwx uIktgEQjfEIRJIfBK0/j+xp8y8lVo/2lFA8or/WdLulgepddgOdzEI6RTkUk45pl Cuq8VVMc49BQaCcgmc0aFmZ9lrhopKii2/31HRca384sk358Otm+9sbomKNdBZbQ QRh+LhqUL53Rgi+69d2vWPfGZMkvE6q4DI89qVdVlzuh1SXI62vwXTRb/rEuEe4= =Q+h5 -----END PGP SIGNATURE----- -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalchemy@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
