enable-one-table-hash-semi-join.diff

diff --git a/sql/opt_subselect.cc b/sql/opt_subselect.cc
index b971c96cda2..3b6ec949ea3 100644
--- a/sql/opt_subselect.cc
+++ b/sql/opt_subselect.cc
@@ -3964,6 +3964,12 @@ void fix_semijoin_strategies_for_picked_join_order(JOIN *join)
       Json_writer_object semijoin_strategy(thd);
       semijoin_strategy.add("semi_join_strategy","FirstMatch");
       Json_writer_array semijoin_plan(thd, "join_order");
+
+      bool one_table_and_buffer_allowed= false;
+      if (first == tablenr && // one table 
+          optimizer_flag(join->thd, OPTIMIZER_SWITCH_SEMIJOIN_WITH_CACHE))
+        one_table_and_buffer_allowed= true;
+
       for (idx= first; idx <= tablenr; idx++)
       {
         Json_writer_object trace_one_table(thd);
@@ -3971,7 +3977,8 @@ void fix_semijoin_strategies_for_picked_join_order(JOIN *join)
         {
           trace_one_table.add_table_name(join->best_positions[idx].table);
         }
-        if (join->best_positions[idx].use_join_buffer)
+        if (join->best_positions[idx].use_join_buffer &&
+            !one_table_and_buffer_allowed)
         {
            best_access_path(join, join->best_positions[idx].table,
                             rem_tables, join->best_positions, idx,