1 files changed, 12 insertions, 6 deletions
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
index 672f11cfcb..29f764e8f4 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -259,10 +259,6 @@ module ActiveRecord
         @use_insert_returning = @config.key?(:insert_returning) ? self.class.type_cast_config_to_boolean(@config[:insert_returning]) : true
       end
 
-      def truncate(table_name, name = nil)
-        exec_query "TRUNCATE TABLE #{quote_table_name(table_name)}", name, []
-      end
-
       # Is this connection alive and ready for queries?
       def active?
         @lock.synchronize do
@@ -351,6 +347,13 @@ module ActiveRecord
         postgresql_version >= 90400
       end
 
+      def supports_optimizer_hints?
+        unless defined?(@has_pg_hint_plan)
+          @has_pg_hint_plan = extension_available?("pg_hint_plan")
+        end
+        @has_pg_hint_plan
+      end
+
       def supports_lazy_transactions?
         true
       end
@@ -381,9 +384,12 @@ module ActiveRecord
         }
       end
 
+      def extension_available?(name)
+        query_value("SELECT true FROM pg_available_extensions WHERE name = #{quote(name)}", "SCHEMA")
+      end
+
       def extension_enabled?(name)
-        res = exec_query("SELECT EXISTS(SELECT * FROM pg_available_extensions WHERE name = '#{name}' AND installed_version IS NOT NULL) as enabled", "SCHEMA")
-        res.cast_values.first
+        query_value("SELECT installed_version IS NOT NULL FROM pg_available_extensions WHERE name = #{quote(name)}", "SCHEMA")
       end
 
       def extensions