set_roll_back should only rollback initialized connections

[jdetaeye]

The exception handler call "connections.all()". This creates a database connection to all defined databases. As a small optimization you can use "connections.all(initialized_only=True)" to rollback only the database to which the current thread has open connections.

(My application can have many databases defined, and this loop is identified as a source of many idle database connections)

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[auvipy]

is it possible to add tests to avoid regression?

[jdetaeye]

@auvipy I just looked into updating

django-rest-framework/tests/test_views.py

Line 113 in a8595a8

def test_class_based_view_exception_handler(self):

with such a test. I failed creating a test case demonstrating the fix (maybe related to the in memory sqlite database used by the test?). Sorry, I won't be able to provide a test.