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Code Issues 32 Releases Wiki Activity

Fixed #27683 -- Made MySQL default to the read committed isolation level.

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Thanks Shai Berger for test help and Adam Johnson for review.
This commit is contained in:
Tim Graham
2017-02-01 15:34:17 -05:00
committed by GitHub
parent c4e18bb1ce
commit 924af638e4
5 changed files with 40 additions and 13 deletions
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23
tests/transactions/tests.py
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@@ -375,18 +375,17 @@ class AtomicMySQLTests(TransactionTestCase):
@skipIf(threading is None, "Test requires threading")
def test_implicit_savepoint_rollback(self):
"""MySQL implicitly rolls back savepoints when it deadlocks (#22291)."""
Reporter.objects.create(id=1)
Reporter.objects.create(id=2)
other_thread_ready = threading.Event()
main_thread_ready = threading.Event()
def other_thread():
try:
with transaction.atomic():
Reporter.objects.create(id=1, first_name="Tintin")
other_thread_ready.set()
# We cannot synchronize the two threads with an event here
# because the main thread locks. Sleep for a little while.
time.sleep(1)
# 2) ... and this line deadlocks. (see below for 1)
Reporter.objects.select_for_update().get(id=1)
main_thread_ready.wait()
# 1) This line locks... (see below for 2)
Reporter.objects.exclude(id=1).update(id=2)
finally:
# This is the thread-local connection, not the main connection.
@@ -394,14 +393,18 @@ class AtomicMySQLTests(TransactionTestCase):
other_thread = threading.Thread(target=other_thread)
other_thread.start()
other_thread_ready.wait()
with self.assertRaisesMessage(OperationalError, 'Deadlock found'):
# Double atomic to enter a transaction and create a savepoint.
with transaction.atomic():
with transaction.atomic():
# 1) This line locks... (see above for 2)
Reporter.objects.create(id=1, first_name="Tintin")
Reporter.objects.select_for_update().get(id=2)
main_thread_ready.set()
# The two threads can't be synchronized with an event here
# because the other thread locks. Sleep for a little while.
time.sleep(1)
# 2) ... and this line deadlocks. (see above for 1)
Reporter.objects.exclude(id=2).update(id=1)
other_thread.join()