diff --git a/synapse/storage/_base.py b/synapse/storage/_base.py
index c328b5274c..e01c61d08d 100644
--- a/synapse/storage/_base.py
+++ b/synapse/storage/_base.py
@@ -167,10 +167,6 @@ class LoggingTransaction(object):
         sql = self.database_engine.convert_param_style(sql)
 
         if args and args[0]:
-            args = list(args)
-            args[0] = [
-                self.database_engine.encode_parameter(a) for a in args[0]
-            ]
             try:
                 sql_logger.debug(
                     "[SQL values] {%s} " + ", ".join(("<%r>",) * len(args[0])),
diff --git a/synapse/storage/engines/postgres.py b/synapse/storage/engines/postgres.py
index 64e34265f6..a323028546 100644
--- a/synapse/storage/engines/postgres.py
+++ b/synapse/storage/engines/postgres.py
@@ -36,9 +36,6 @@ class PostgresEngine(object):
     def convert_param_style(self, sql):
         return sql.replace("?", "%s")
 
-    def encode_parameter(self, param):
-        return param
-
     def on_new_connection(self, db_conn):
         db_conn.set_isolation_level(
             self.module.extensions.ISOLATION_LEVEL_REPEATABLE_READ
diff --git a/synapse/storage/engines/sqlite3.py b/synapse/storage/engines/sqlite3.py
index 7b49157cbd..ff13d8006a 100644
--- a/synapse/storage/engines/sqlite3.py
+++ b/synapse/storage/engines/sqlite3.py
@@ -26,9 +26,6 @@ class Sqlite3Engine(object):
     def convert_param_style(self, sql):
         return sql
 
-    def encode_parameter(self, param):
-        return param
-
     def on_new_connection(self, db_conn):
         self.prepare_database(db_conn)