From caf9901c1bcdcf97e0034a01b4a619e2eb1e5bc3 Mon Sep 17 00:00:00 2001
From: Joel Barciauskas <joel@edx.org>
Date: Fri, 9 Dec 2016 15:04:29 -0500
Subject: [PATCH] [PLAT-1109] Suppress IntegrityErrors caused by race condition
Suppress IntegrityErrors that may be caused by a race condition
between processes resulting from a slow-loading page and a user refreshing the
page.
---
.../courseware/user_state_client.py | 28 +++++++++++++------
1 file changed, 19 insertions(+), 9 deletions(-)
diff --git a/lms/djangoapps/courseware/user_state_client.py b/lms/djangoapps/courseware/user_state_client.py
index 02316fec344..ecf6647613a 100644
--- a/lms/djangoapps/courseware/user_state_client.py
+++ b/lms/djangoapps/courseware/user_state_client.py
@@ -271,15 +271,25 @@ class DjangoXBlockUserStateClient(XBlockUserStateClient):
evt_time = time()
for usage_key, state in block_keys_to_state.items():
- student_module, created = StudentModule.objects.get_or_create(
- student=user,
- course_id=usage_key.course_key,
- module_state_key=usage_key,
- defaults={
- 'state': json.dumps(state),
- 'module_type': usage_key.block_type,
- },
- )
+ try:
+ student_module, created = StudentModule.objects.get_or_create(
+ student=user,
+ course_id=usage_key.course_key,
+ module_state_key=usage_key,
+ defaults={
+ 'state': json.dumps(state),
+ 'module_type': usage_key.block_type,
+ },
+ )
+ except IntegrityError:
+ # PLAT-1109 - Until we switch to read committed, we cannot rely
+ # on get_or_create to be able to see rows created in another
+ # process. This seems to happen frequently, and ignoring it is the
+ # best course of action for now
+ log.warning("set_many: IntegrityError for student {} - course_id {} - usage key {}".format(
+ user, repr(unicode(usage_key.course_key)), usage_key
+ ))
+ return
num_fields_before = num_fields_after = num_new_fields_set = len(state)
num_fields_updated = 0
--
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