is_dirty() in the transactions middleware blocks commit for Postgre

[Jeffrey]

In its default operation Postgre makes a shadow copy of a table for reading, and this persists until you explicitly commit your transaction. However, the TransactionsMiddleware class only calls commit when transaction.is_dirty() returns true. If you only read from the database, commit will never get called.

Possibly the is_dirty() check should be bypassed (or perhaps always return True) for postgres.

[Jeffrey]

See:

• ​http://code.djangoproject.com/browser/django/trunk/django/middleware/transaction.py

• ​http://code.djangoproject.com/browser/django/trunk/django/db/transaction.py

[Shai Berger]

PostgreSQL here is just a special case; the behavior is wrong everywhere. See #9964.

[Jacob]

Duplicate of #9964.