[1.8.x] Fixed #23372 -- Made loaddata faster if it doesn't find any fixtures.

Django's test suite often tries to load fixture files from apps that have
no fixtures at all. This creates a lot of unnecessary disabling and
enabling of constraints which can be expensive on some database.

To speed this up, loaddata now first checks if any fixture file matches.
If no fixture file is matched, then the command exits before disabling
and enabling of constraints is done.

The main benefit of this change is seen on MSSQL, where tests on
Django 1.8 run hours faster.

Backport of ee9f4686b19e2b4a68f5cb4f9d61dc045c1d4c63 from master

0 files changed, 0 insertions, 0 deletions