post-merge fixes: get MWL#90 code to work with MWL#89's

way of processing prepared statements:
- conversion subquery_predicate -> TABLE_LIST is once per-statement
- However, the code must take into account that materialized temptable
  is dropped and re-created on each execution (the tricky part is that 
  at start of n-th EXECUTE we have TABLE_LIST object but not its TABLE object)
- IN-equality is injected into WHERE on every execution.

sql/item_subselect.cc

@@ -4064,6 +4064,7 @@ bool subselect_hash_sj_engine::make_semi_join_conds()
   context->init();
   context->first_name_resolution_table=
     context->last_name_resolution_table= tmp_table_ref;
+  semi_join_conds_context= context;
   
   for (uint i= 0; i < item_in->left_expr->cols(); i++)
   {

sql/item_subselect.h

@@ -839,6 +839,8 @@ class subselect_hash_sj_engine : public subselect_engine
     not equal to the search key in SQL terms.
   */
   Item_cond_and *semi_join_conds;
+  Name_resolution_context *semi_join_conds_context;
+
 
   subselect_hash_sj_engine(THD *thd, Item_subselect *in_predicate,
                            subselect_single_select_engine *old_engine)

sql/opt_subselect.cc

@@ -1397,6 +1397,7 @@ static bool convert_subq_to_jtbm(JOIN *parent_join,
 
   jtbm->table->tablenr= parent_join->table_count;
   jtbm->table->map= table_map(1) << (parent_join->table_count);
+  jtbm->jtbm_table_no= jtbm->table->tablenr;
 
   parent_join->table_count++;
   DBUG_ASSERT(parent_join->table_count < MAX_TABLES);
@@ -1409,7 +1410,7 @@ static bool convert_subq_to_jtbm(JOIN *parent_join,
   create_subquery_temptable_name(tbl_alias, hash_sj_engine->materialize_join->
                                               select_lex->select_number);
   jtbm->alias= tbl_alias;
-
+#if 0
   /* Inject sj_on_expr into the parent's WHERE or ON */
   if (emb_tbl_nest)
   {
@@ -1426,7 +1427,7 @@ static bool convert_subq_to_jtbm(JOIN *parent_join,
     parent_join->conds->fix_fields(parent_join->thd, &parent_join->conds);
     parent_join->select_lex->where= parent_join->conds;
   }
-
+#endif
   /* Don't unlink the child subselect, as the subquery will be used. */
 
   DBUG_RETURN(FALSE);

sql/sql_base.cc

@@ -7768,7 +7768,14 @@ bool setup_tables(THD *thd, Name_resolution_context *context,
       first_select_table= 0;
       tablenr= 0;
     }
-    setup_table_map(table, table_list, tablenr);
+
+    if (table_list->jtbm_subselect)
+    {
+      table_list->jtbm_table_no= tablenr;
+    }
+    else
+      setup_table_map(table, table_list, tablenr);
+
     if (table_list->process_index_hints(table))
       DBUG_RETURN(1);
   }
@@ -7797,17 +7804,38 @@ bool setup_tables(THD *thd, Name_resolution_context *context,
       if (res)
         DBUG_RETURN(1);
     }
+
     if (table_list->jtbm_subselect)
     {
-      Item *item= table_list->jtbm_subselect;
-      if (item->fix_fields(thd, &item))
+      Item *item= table_list->jtbm_subselect->optimizer;
+      if (table_list->jtbm_subselect->optimizer->fix_fields(thd, &item))
       {
         my_error(ER_TOO_MANY_TABLES,MYF(0),MAX_TABLES); /* psergey-todo: WHY ER_TOO_MANY_TABLES ???*/
         DBUG_RETURN(1);
       }
-      DBUG_ASSERT(item == table_list->jtbm_subselect);
+      DBUG_ASSERT(item == table_list->jtbm_subselect->optimizer);
+  /*    
+      {
+        Item_in_subselect *subq_pred= table_list->jtbm_subselect;
+        double rows;
+        double read_time;
+
+        // psergey-merge: disable IN->EXISTS for JTBM subqueries, for now.
+        subq_pred->in_strategy &= ~SUBS_IN_TO_EXISTS;
+        subq_pred->optimize(&rows, &read_time);
+
+        subq_pred->jtbm_read_time= read_time;
+        subq_pred->jtbm_record_count=rows;
+        subq_pred->is_jtbm_merged= TRUE;
+      }
+      // The following call should never ever be made on its own anymore:
       if (table_list->jtbm_subselect->setup_mat_engine()) // dont_switch_arena=FALSE 
         DBUG_RETURN(1);
+  */
+      //psergey-merge: fix prepared statements:
+      //subselect_hash_sj_engine *mat_engine= 
+      //  (subselect_hash_sj_engine*)table_list->jtbm_subselect->engine;
+      //table= table_list->table= mat_engine->tmp_table;
     }
   }
 

sql/sql_select.cc

@@ -766,6 +766,57 @@ JOIN::prepare(Item ***rref_pointer_array,
 }
 
 
+void
+inject_jtbm_conds(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");
+
+  
+  while ((table= li++))
+  {
+    Item_in_subselect *item;
+    
+    if ((item= table->jtbm_subselect))
+    {
+      Item_in_subselect *subq_pred= item;
+      double rows;
+      double read_time;
+
+      // psergey-merge: disable IN->EXISTS for JTBM subqueries, for now.
+      subq_pred->in_strategy &= ~SUBS_IN_TO_EXISTS;
+      subq_pred->optimize(&rows, &read_time);
+
+      subq_pred->jtbm_read_time= read_time;
+      subq_pred->jtbm_record_count=rows;
+      subq_pred->is_jtbm_merged= TRUE;
+
+      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;
+
+      setup_table_map(table->table, table, table->jtbm_table_no);
+
+      Item *sj_conds= hash_sj_engine->semi_join_conds;
+
+      (*join_where)= and_items(*join_where, sj_conds);
+      (*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);
+    }
+  }
+  DBUG_VOID_RETURN;
+}
+
 /**
   global select optimisation.
 
@@ -856,6 +907,9 @@ JOIN::optimize()
     if (arena)
       thd->restore_active_arena(arena, &backup);
   }
+  
+  //psergey-merge
+  inject_jtbm_conds(this, join_list, &conds);
 
   conds= optimize_cond(this, conds, join_list, &cond_value, &cond_equal);   
   if (thd->is_error())

sql/table.h

@@ -1272,6 +1272,7 @@ struct TABLE_LIST
 
   /* If this is a jtbm semi-join object: corresponding subselect predicate */
   Item_in_subselect  *jtbm_subselect;
+  uint jtbm_table_no;
 
   SJ_MATERIALIZATION_INFO *sj_mat_info;