fix: Batch requests to snuba for TSDB queries (#14379)

Some accounts are not getting their weekly reports.

This is cause when the report generation is scheduled, sentry makes a call to snuba with all the new issue IDs and reopened issue IDs. Snuba has a max query size of 500 kB (i.e. the SQL cannot be more than 500 kB). The max query size is not a problem of most cases but does become a problem for larger organizations who open a lot of issues in one week.

[Here's the sentry error](https://sentry.io/organizations/sentry/issues/871693042/).

src/sentry/tasks/reports.py

@@ -29,13 +29,17 @@
 from sentry.utils import json, redis
 from sentry.utils.dates import floor_to_utc_day, to_datetime, to_timestamp
 from sentry.utils.email import MessageBuilder
+from sentry.utils.iterators import chunked
 from sentry.utils.math import mean
 from six.moves import reduce
 
+
 date_format = functools.partial(dateformat.format, format_string="F jS, Y")
 
 logger = logging.getLogger(__name__)
 
+BATCH_SIZE = 30000
+
 
 def _get_organization_queryset():
     return Organization.objects.filter(status=OrganizationStatus.VISIBLE)
@@ -211,6 +215,15 @@ def get_aggregate_value(start, stop):
     ]
 
 
+def get_event_counts(issue_ids, start, stop, rollup):
+    combined = {}
+
+    for chunk in chunked(issue_ids, BATCH_SIZE):
+        combined.update(tsdb.get_sums(tsdb.models.group, chunk, start, stop, rollup=rollup))
+
+    return combined
+
+
 def prepare_project_issue_summaries(interval, project):
     start, stop = interval
 
@@ -244,10 +257,7 @@ def prepare_project_issue_summaries(interval, project):
     )
 
     rollup = 60 * 60 * 24
-
-    event_counts = tsdb.get_sums(
-        tsdb.models.group, new_issue_ids | reopened_issue_ids, start, stop, rollup=rollup
-    )
+    event_counts = get_event_counts(new_issue_ids | reopened_issue_ids, start, stop, rollup)
 
     new_issue_count = sum(event_counts[id] for id in new_issue_ids)
     reopened_issue_count = sum(event_counts[id] for id in reopened_issue_ids)

tests/sentry/tasks/test_reports.py

@@ -29,8 +29,9 @@
     prepare_reports,
     safe_add,
     user_subscribed_to_organization_reports,
+    prepare_project_issue_summaries,
 )
-from sentry.testutils.cases import TestCase
+from sentry.testutils.cases import TestCase, SnubaTestCase
 from sentry.utils.dates import to_datetime, to_timestamp
 from six.moves import xrange
 
@@ -193,7 +194,7 @@ def test_calendar_range():
     )
 
 
-class ReportTestCase(TestCase):
+class ReportTestCase(TestCase, SnubaTestCase):
     def test_integration(self):
         Project.objects.all().delete()
 
@@ -256,3 +257,41 @@ def test_user_subscribed_to_organization_reports(self):
 
         set_option_value([organization.id])
         assert user_subscribed_to_organization_reports(user, organization) is False
+
+    @mock.patch("sentry.tasks.reports.BATCH_SIZE", 1)
+    def test_paginates_and_reassumbles_result(self):
+        import copy
+        from datetime import timedelta
+        from django.utils import timezone
+
+        from sentry.testutils.factories import DEFAULT_EVENT_DATA
+
+        self.login_as(user=self.user)
+
+        now = timezone.now()
+        min_ago = (now - timedelta(minutes=1)).isoformat()[:19]
+        two_min_ago = now - timedelta(minutes=2)
+
+        self.store_event(
+            data={
+                "event_id": "a" * 32,
+                "message": "message",
+                "timestamp": min_ago,
+                "stacktrace": copy.deepcopy(DEFAULT_EVENT_DATA["stacktrace"]),
+                "fingerprint": ["group-1"],
+            },
+            project_id=self.project.id,
+        )
+
+        self.store_event(
+            data={
+                "event_id": "b" * 32,
+                "message": "message",
+                "timestamp": min_ago,
+                "stacktrace": copy.deepcopy(DEFAULT_EVENT_DATA["stacktrace"]),
+                "fingerprint": ["group-2"],
+            },
+            project_id=self.project.id,
+        )
+
+        assert prepare_project_issue_summaries([two_min_ago, now], self.project) == [2, 0, 0]