3 files changed, 25 insertions, 0 deletions
diff --git a/lib/sqlalchemy/dialects/postgresql/asyncpg.py b/lib/sqlalchemy/dialects/postgresql/asyncpg.py
index a84bece4f..4cc04d20a 100644
--- a/lib/sqlalchemy/dialects/postgresql/asyncpg.py
+++ b/lib/sqlalchemy/dialects/postgresql/asyncpg.py
@@ -741,6 +741,12 @@ class AsyncAdapt_asyncpg_connection(AdaptedConnection):
         else:
             self.isolation_level = self._isolation_setting
 
+    def ping(self):
+        try:
+            _ = self.await_(self._connection.fetchrow(";"))
+        except Exception as error:
+            self._handle_exception(error)
+
     def set_isolation_level(self, level):
         if self._started:
             self.rollback()
@@ -996,6 +1002,17 @@ class PGDialect_asyncpg(PGDialect):
         util.coerce_kw_type(opts, "port", int)
         return ([], opts)
 
+    def do_ping(self, dbapi_connection):
+        try:
+            dbapi_connection.ping()
+        except self.dbapi.Error as err:
+            if self.is_disconnect(err, dbapi_connection, None):
+                return False
+            else:
+                raise
+        else:
+            return True
+
     @classmethod
     def get_pool_class(cls, url):
 
diff --git a/lib/sqlalchemy/dialects/postgresql/pg8000.py b/lib/sqlalchemy/dialects/postgresql/pg8000.py
index ce9a3bb6c..d4b159b73 100644
--- a/lib/sqlalchemy/dialects/postgresql/pg8000.py
+++ b/lib/sqlalchemy/dialects/postgresql/pg8000.py
@@ -559,5 +559,9 @@ class PGDialect_pg8000(PGDialect):
         else:
             return None
 
+    @util.memoized_property
+    def _dialect_specific_select_one(self):
+        return ";"
+
 
 dialect = PGDialect_pg8000
diff --git a/lib/sqlalchemy/dialects/postgresql/psycopg.py b/lib/sqlalchemy/dialects/postgresql/psycopg.py
index 633357a74..371bf2bc2 100644
--- a/lib/sqlalchemy/dialects/postgresql/psycopg.py
+++ b/lib/sqlalchemy/dialects/postgresql/psycopg.py
@@ -505,6 +505,10 @@ class PGDialect_psycopg(_PGDialect_common_psycopg):
         else:
             self.do_commit(connection.connection)
 
+    @util.memoized_property
+    def _dialect_specific_select_one(self):
+        return ";"
+
 
 class AsyncAdapt_psycopg_cursor:
     __slots__ = ("_cursor", "await_", "_rows")