Fixed #19351 -- SQLite bulk_insert of more than 500 single-field objs

django/db/backends/sqlite3/base.py

@@ -120,8 +120,12 @@ class DatabaseOperations(BaseDatabaseOperations):
         """
         SQLite has a compile-time default (SQLITE_LIMIT_VARIABLE_NUMBER) of
         999 variables per query.
+
+        If there is just single field to insert, then we can hit another
+        limit, SQLITE_MAX_COMPOUND_SELECT which defaults to 500.
         """
-        return (999 // len(fields)) if len(fields) > 0 else len(objs)
+        limit = 999 if len(fields) > 1 else 500
+        return (limit // len(fields)) if len(fields) > 0 else len(objs)
 
     def date_extract_sql(self, lookup_type, field_name):
         # sqlite doesn't support extract, so we fake it with the user-defined

tests/regressiontests/bulk_create/tests.py

@@ -102,6 +102,14 @@ class BulkCreateTests(TestCase):
             101)
         self.assertEqual(TwoFields.objects.filter(f2__gte=901).count(), 101)
 
+    @skipUnlessDBFeature('has_bulk_insert')
+    def test_large_single_field_batch(self):
+        # SQLite had a problem with more than 500 UNIONed selects in single
+        # query.
+        Restaurant.objects.bulk_create([
+            Restaurant() for i in range(0, 501)
+        ])
+
     @skipUnlessDBFeature('has_bulk_insert')
     def test_large_batch_efficiency(self):
         with override_settings(DEBUG=True):