BUG#868908: Crash in check_simple_equality() with semijoin + materialization + prepared statement

- Part2: safety and code cleanup

sql/item_subselect.cc

@@ -616,7 +616,7 @@ int Item_in_subselect::optimize(double *out_rows, double *cost)
   thd->lex->current_select= join->select_lex;
   if ((res= join->optimize()))
     DBUG_RETURN(res);
-//psergey-todo: subq predicate can be made forced const!
+
   /* Calculate #rows and cost of join execution */
   join->get_partial_cost_and_fanout(join->table_count - join->const_tables, 
                                     table_map(-1),
@@ -1197,7 +1197,8 @@ Item_in_subselect::Item_in_subselect(Item * left_exp,
   Item_exists_subselect(), 
   left_expr_cache(0), first_execution(TRUE), in_strategy(SUBS_NOT_TRANSFORMED),
   optimizer(0), pushed_cond_guards(NULL), emb_on_expr_nest(NULL),
-  is_jtbm_merged(FALSE), is_flattenable_semijoin(FALSE),
+  is_jtbm_merged(FALSE), is_jtbm_const_tab(FALSE), 
+  is_flattenable_semijoin(FALSE),
   is_registered_semijoin(FALSE), 
   upper_item(0)
 {
@@ -4182,6 +4183,8 @@ bool subselect_hash_sj_engine::init(List<Item> *tmp_columns, uint subquery_id)
   */
   if (tmp_table->s->keys == 0)
   {
+    //fprintf(stderr, "Q: %s\n", current_thd->query());
+    DBUG_ASSERT(0);
     DBUG_ASSERT(
       tmp_table->s->uniques ||
       tmp_table->key_info->key_length >= tmp_table->file->max_key_length() ||

sql/item_subselect.h

@@ -491,7 +491,7 @@ public:
     :Item_exists_subselect(), left_expr_cache(0), first_execution(TRUE),
      abort_on_null(0), in_strategy(SUBS_NOT_TRANSFORMED), optimizer(0),
     pushed_cond_guards(NULL), func(NULL), emb_on_expr_nest(NULL), 
-    is_jtbm_merged(FALSE),
+    is_jtbm_merged(FALSE), is_jtbm_const_tab(FALSE),
     upper_item(0)
     {}
   void cleanup();

sql/opt_subselect.cc

@@ -1431,21 +1431,11 @@ static bool convert_subq_to_jtbm(JOIN *parent_join,
   DBUG_ENTER("convert_subq_to_jtbm");
   bool optimization_delayed= TRUE;
   subq_pred->set_strategy(SUBS_MATERIALIZATION);
-//  if (subq_pred->optimize(&rows, &read_time))  psergey-fix
-//    DBUG_RETURN(TRUE);
 
   subq_pred->jtbm_read_time= read_time;
   subq_pred->jtbm_record_count=rows;
   subq_pred->is_jtbm_merged= TRUE;
 
-/* psergey-fix
-  if (subq_pred->engine->engine_type() != subselect_engine::HASH_SJ_ENGINE)
-  {
-    *remove_item= FALSE;
-    DBUG_RETURN(FALSE);
-  }
-*/
-
   *remove_item= TRUE;
 
   TABLE_LIST *jtbm;

sql/sql_select.cc

@@ -832,12 +832,12 @@ TABLE *create_dummy_tmp_table(THD *thd)
 
 
 void
-inject_jtbm_conds(JOIN *join, List<TABLE_LIST> *join_list, Item **join_where)
+setup_jtbm_semi_joins(JOIN *join, List<TABLE_LIST> *join_list, Item **join_where)
 {
   TABLE_LIST *table;
   NESTED_JOIN *nested_join;
   List_iterator<TABLE_LIST> li(*join_list);
-  DBUG_ENTER("inject_jtbm_conds");
+  DBUG_ENTER("setup_jtbm_semi_joins");
 
   
   while ((table= li++))
@@ -880,7 +880,6 @@ inject_jtbm_conds(JOIN *join, List<TABLE_LIST> *join_list, Item **join_where)
         table->table->pos_in_table_list= table;
 
         setup_table_map(table->table, table, table->jtbm_table_no);
-
       }
       else
       {
@@ -889,7 +888,6 @@ inject_jtbm_conds(JOIN *join, List<TABLE_LIST> *join_list, Item **join_where)
         subselect_hash_sj_engine *hash_sj_engine=
           ((subselect_hash_sj_engine*)item->engine);
         
-        //repeat of convert_subq_to_jtbm:
         table->table= hash_sj_engine->tmp_table;
         table->table->pos_in_table_list= table;
 
@@ -900,13 +898,12 @@ inject_jtbm_conds(JOIN *join, List<TABLE_LIST> *join_list, Item **join_where)
         (*join_where)= and_items(*join_where, sj_conds);
         if (!(*join_where)->fixed)
           (*join_where)->fix_fields(join->thd, join_where);
-        //parent_join->select_lex->where= parent_join->conds;
       }
     }
 
     if ((nested_join= table->nested_join))
     {
-      inject_jtbm_conds(join, &nested_join->join_list, join_where);
+      setup_jtbm_semi_joins(join, &nested_join->join_list, join_where);
     }
   }
   DBUG_VOID_RETURN;
@@ -1036,7 +1033,7 @@ JOIN::optimize()
       thd->restore_active_arena(arena, &backup);
   }
   
-  inject_jtbm_conds(this, join_list, &conds);
+  setup_jtbm_semi_joins(this, join_list, &conds);
 
   conds= optimize_cond(this, conds, join_list, &cond_value, &cond_equal);
      

sql/table.cc

@@ -5922,8 +5922,8 @@ bool TABLE_LIST::init_derived(THD *thd, bool init_view)
 int TABLE_LIST::fetch_number_of_rows()
 {
   int error= 0;
-  if (jtbm_subselect) /* psergey-todo: how did we work before? */
-    return 0; /*psergey-todo: check if we still need to set it? */
+  if (jtbm_subselect)
+    return 0;
   if (is_materialized_derived() && !fill_me)
 
   {