set_rollback 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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Description

Please describe your pull request. If it fixes a bug or resolves a feature request, be sure to link to that issue. When linking to an issue, please use refs #... in the description of the pull request.

[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.

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[Copilot]

Pull Request Overview

This pull request optimizes the rollback process by limiting the rollback to initialized database connections only.

• Updated the set_rollback function to use the "initialized_only" flag
• Reduces unnecessary database connection instantiation during exception handling

[peterthomassen]

This looks very reasonable, and I've followed the flow into what Django does when this is called, and it lgtm.

I've also verified that this is supported by all Django releases we rely on. I guess we didn't have this initially because it was only introduced in Django 4.1.

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This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[browniebroke]

How does it work with that other PR?

• Improve set_rollback() behaviour #6922

Are they related, complementary?