- work in progress, will squash

1 files changed, 3 insertions, 10 deletions

diff --git a/lib/sqlalchemy/dialects/mysql/base.py b/lib/sqlalchemy/dialects/mysql/base.py
index 324ff2d36..971005a84 100644
--- a/lib/sqlalchemy/dialects/mysql/base.py
+++ b/lib/sqlalchemy/dialects/mysql/base.py
@@ -1437,17 +1437,10 @@ class MySQLCompiler(compiler.SQLCompiler):
              self.process(join.onclause, **kwargs)))
 
     def for_update_clause(self, select):
-        # backwards compatibility
-        if isinstance(select.for_update, bool):
-            return ' FOR UPDATE'
-        elif isinstance(select.for_update, str):
-            if select.for_update == 'read':
-                return ' LOCK IN SHARE MODE'
-
-        if select.for_update.mode == 'read':
-            return ' LOCK IN SHARE MODE'
+        if select._for_update_arg.read:
+            return " LOCK IN SHARE MODE"
         else:
-            return super(MySQLCompiler, self).for_update_clause(select)
+            return " FOR UPDATE"
 
     def limit_clause(self, select):
         # MySQL supports: