Refs #28478 -- Prevented timezone assignment for unusable PostgreSQL connections.

1 files changed, 5 insertions, 1 deletions

diff --git a/django/db/backends/postgresql/base.py b/django/db/backends/postgresql/base.py
index 9de9b44735..e9db668a4d 100644
--- a/django/db/backends/postgresql/base.py
+++ b/django/db/backends/postgresql/base.py
@@ -195,7 +195,8 @@ class DatabaseWrapper(BaseDatabaseWrapper):
         return connection
 
     def ensure_timezone(self):
-        self.ensure_connection()
+        if not self.is_usable():
+            return False
         conn_timezone_name = self.connection.get_parameter_status('TimeZone')
         timezone_name = self.timezone_name
         if timezone_name and conn_timezone_name != timezone_name:
@@ -207,6 +208,7 @@ class DatabaseWrapper(BaseDatabaseWrapper):
     def init_connection_state(self):
         self.connection.set_client_encoding('UTF8')
 
+        self.ensure_connection()
         timezone_changed = self.ensure_timezone()
         if timezone_changed:
             # Commit after setting the time zone (see #17062)
@@ -246,6 +248,8 @@ class DatabaseWrapper(BaseDatabaseWrapper):
         self.cursor().execute('SET CONSTRAINTS ALL DEFERRED')
 
     def is_usable(self):
+        if self.connection is None:
+            return False
         try:
             # Use a psycopg cursor directly, bypassing Django's utilities.
             self.connection.cursor().execute("SELECT 1")