Combined MySQL backend server info queries.

django/db/backends/mysql/base.py

@@ -355,10 +355,32 @@ class DatabaseWrapper(BaseDatabaseWrapper):
         return {}
 
     @cached_property
-    def mysql_server_info(self):
+    def mysql_server_data(self):
         with self.temporary_connection() as cursor:
-            cursor.execute('SELECT VERSION()')
-            return cursor.fetchone()[0]
+            # Select some server variables and test if the time zone
+            # definitions are installed. CONVERT_TZ returns NULL if 'UTC'
+            # timezone isn't loaded into the mysql.time_zone table.
+            cursor.execute("""
+                SELECT VERSION(),
+                       @@sql_mode,
+                       @@default_storage_engine,
+                       @@sql_auto_is_null,
+                       @@lower_case_table_names,
+                       CONVERT_TZ('2001-01-01 01:00:00', 'UTC', 'UTC') IS NOT NULL
+            """)
+            row = cursor.fetchone()
+        return {
+            'version': row[0],
+            'sql_mode': row[1],
+            'default_storage_engine': row[2],
+            'sql_auto_is_null': bool(row[3]),
+            'lower_case_table_names': bool(row[4]),
+            'has_zoneinfo_database': bool(row[5]),
+        }
+
+    @cached_property
+    def mysql_server_info(self):
+        return self.mysql_server_data['version']
 
     @cached_property
     def mysql_version(self):
@@ -373,7 +395,5 @@ class DatabaseWrapper(BaseDatabaseWrapper):
 
     @cached_property
     def sql_mode(self):
-        with self.cursor() as cursor:
-            cursor.execute('SELECT @@sql_mode')
-            sql_mode = cursor.fetchone()
-        return set(sql_mode[0].split(',') if sql_mode else ())
+        sql_mode = self.mysql_server_data['sql_mode']
+        return set(sql_mode.split(',') if sql_mode else ())

django/db/backends/mysql/features.py

@@ -50,10 +50,7 @@ class DatabaseFeatures(BaseDatabaseFeatures):
     @cached_property
     def _mysql_storage_engine(self):
         "Internal method used in Django tests. Don't rely on this from your code"
-        with self.connection.cursor() as cursor:
-            cursor.execute("SELECT ENGINE FROM INFORMATION_SCHEMA.ENGINES WHERE SUPPORT = 'DEFAULT'")
-            result = cursor.fetchone()
-        return result[0]
+        return self.connection.mysql_server_data['default_storage_engine']
 
     @cached_property
     def update_can_self_select(self):
@@ -82,18 +79,11 @@ class DatabaseFeatures(BaseDatabaseFeatures):
 
     @cached_property
     def has_zoneinfo_database(self):
-        # Test if the time zone definitions are installed. CONVERT_TZ returns
-        # NULL if 'UTC' timezone isn't loaded into the mysql.time_zone.
-        with self.connection.cursor() as cursor:
-            cursor.execute("SELECT CONVERT_TZ('2001-01-01 01:00:00', 'UTC', 'UTC')")
-            return cursor.fetchone()[0] is not None
+        return self.connection.mysql_server_data['has_zoneinfo_database']
 
     @cached_property
     def is_sql_auto_is_null_enabled(self):
-        with self.connection.cursor() as cursor:
-            cursor.execute('SELECT @@SQL_AUTO_IS_NULL')
-            result = cursor.fetchone()
-            return result and result[0] == 1
+        return self.connection.mysql_server_data['sql_auto_is_null']
 
     @cached_property
     def supports_over_clause(self):
@@ -150,10 +140,7 @@ class DatabaseFeatures(BaseDatabaseFeatures):
 
     @cached_property
     def ignores_table_name_case(self):
-        with self.connection.cursor() as cursor:
-            cursor.execute('SELECT @@LOWER_CASE_TABLE_NAMES')
-            result = cursor.fetchone()
-            return result and result[0] != 0
+        return self.connection.mysql_server_data['lower_case_table_names']
 
     @cached_property
     def supports_default_in_lead_lag(self):

tests/check_framework/test_database.py

@@ -29,20 +29,22 @@ class DatabaseCheckTests(TestCase):
             'STRICT_TRANS_TABLES',
             'STRICT_ALL_TABLES',
         ]
-        for response in good_sql_modes:
-            with mock.patch(
-                'django.db.backends.utils.CursorWrapper.fetchone', create=True,
-                return_value=(response,)
+        for sql_mode in good_sql_modes:
+            with mock.patch.object(
+                connection, 'mysql_server_data', {'sql_mode': sql_mode},
             ):
                 self.assertEqual(check_database_backends(databases=self.databases), [])
             _clean_sql_mode()
 
         bad_sql_modes = ['', 'WHATEVER']
-        for response in bad_sql_modes:
-            with mock.patch(
-                'django.db.backends.utils.CursorWrapper.fetchone', create=True,
-                return_value=(response,)
-            ):
+        for sql_mode in bad_sql_modes:
+            mocker_default = mock.patch.object(
+                connection, 'mysql_server_data', {'sql_mode': sql_mode},
+            )
+            mocker_other = mock.patch.object(
+                connections['other'], 'mysql_server_data', {'sql_mode': sql_mode},
+            )
+            with mocker_default, mocker_other:
                 # One warning for each database alias
                 result = check_database_backends(databases=self.databases)
                 self.assertEqual(len(result), 2)