diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index bea748562eb..825d3c870d8 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -9788,6 +9788,7 @@ create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
   table->in_use= thd;
   table->quick_keys.init();
   table->covering_keys.init();
+  table->merge_keys.init();
   table->keys_in_use_for_query.init();
 
   table->s= share;
diff --git a/sql/table.cc b/sql/table.cc
index 17454ffb012..f67929ad96b 100644
--- a/sql/table.cc
+++ b/sql/table.cc
@@ -1652,6 +1652,7 @@ int open_table_from_share(THD *thd, TABLE_SHARE *share, const char *alias,
     goto err;
   outparam->quick_keys.init();
   outparam->covering_keys.init();
+  outparam->merge_keys.init();
   outparam->keys_in_use_for_query.init();
 
   /* Allocate handler */