Commit message: MDEV-22464 Server crash on UPDATE with nested subquery

Uninitialized ref_pointer_array[] because setup_fields() got empty
fields list.  mysql_multi_update() for some reason does that by
substituting the fields list with empty total_list for the
mysql_select() call (looks like wrong merge since total_list is not
used anywhere else and is always empty). The fix would be to return
back the original fields list. But this fails update_use_source.test
case:

  --error ER_BAD_FIELD_ERROR
  update v1 set t1c1=2 order by 1;

Actually not failing the above seems to be ok.

The other fix would be to keep resolve_in_select_list false (and that
keeps outer context from being resolved in
Item_ref::fix_fields()). This fix is more consistent with how SELECT
behaves:

  --error ER_SUBQUERY_NO_1_ROW
  select a from t1 where a= (select 2 from t1 having (a = 3));

So this patch implements this fix.
CVE: CVE-2021-46662
CWE: NVD-CWE-noinfo
Vulnerability description: MariaDB through 10.5.9 allows a set_var.cc application crash via certain uses of an UPDATE statement in conjunction with a nested subquery.

Project: server

join_ft_read_first(JOIN_TAB *tab)
{
  int error;
  TABLE *table= tab->table;

  if (!table->file->inited &&
      (error= table->file->ha_index_init(tab->ref.key, 1)))
  {
    (void) report_error(table, error);
    return 1;
  }

  table->file->ft_init();

  if (unlikely((error= table->file->ha_ft_read(table->record[0]))))
    return report_error(table, error);
  return 0;
}

Project: server

join_tab_cmp_straight(const void *dummy, const void* ptr1, const void* ptr2)
{
  JOIN_TAB *jt1= *(JOIN_TAB**) ptr1;
  JOIN_TAB *jt2= *(JOIN_TAB**) ptr2;

  /*
    We don't do subquery flattening if the parent or child select has
    STRAIGHT_JOIN modifier. It is complicated to implement and the semantics
    is hardly useful.
  */
  DBUG_ASSERT(!jt1->emb_sj_nest);
  DBUG_ASSERT(!jt2->emb_sj_nest);

  int cmp;
  if ((cmp= compare_embedding_subqueries(jt1, jt2)) != 0)
    return cmp;

  if (jt1->dependent & jt2->table->map)
    return 1;
  if (jt2->dependent & jt1->table->map)
    return -1;
  return jt1 > jt2 ? 1 : (jt1 < jt2 ? -1 : 0);
}

Project: server

bool JOIN::rollup_process_const_fields()
{
  ORDER *group_tmp;
  Item *item;
  List_iterator<Item> it(all_fields);

  for (group_tmp= group_list; group_tmp; group_tmp= group_tmp->next)
  {
    if (!(*group_tmp->item)->const_item())
      continue;
    while ((item= it++))
    {
      if (*group_tmp->item == item)
      {
        Item* new_item= new (thd->mem_root) Item_func_rollup_const(thd, item);
        if (!new_item)
          return 1;
        new_item->fix_fields(thd, (Item **) 0);
        thd->change_item_tree(it.ref(), new_item);
        for (ORDER *tmp= group_tmp; tmp; tmp= tmp->next)
        {
          if (*tmp->item == item)
            thd->change_item_tree(tmp->item, new_item);
        }
        break;
      }
    }
    it.rewind();
  }
  return 0;
}

Project: server

setup_copy_fields(THD *thd, TMP_TABLE_PARAM *param,
		  Ref_ptr_array ref_pointer_array,
		  List<Item> &res_selected_fields, List<Item> &res_all_fields,
		  uint elements, List<Item> &all_fields)
{
  Item *pos;
  List_iterator_fast<Item> li(all_fields);
  Copy_field *copy= NULL;
  Copy_field *copy_start __attribute__((unused));
  res_selected_fields.empty();
  res_all_fields.empty();
  List_iterator_fast<Item> itr(res_all_fields);
  List<Item> extra_funcs;
  uint i, border= all_fields.elements - elements;
  DBUG_ENTER("setup_copy_fields");

  if (param->field_count && 
      !(copy=param->copy_field= new (thd->mem_root) Copy_field[param->field_count]))
    goto err2;

  param->copy_funcs.empty();
  copy_start= copy;
  for (i= 0; (pos= li++); i++)
  {
    Field *field;
    uchar *tmp;
    Item *real_pos= pos->real_item();
    /*
      Aggregate functions can be substituted for fields (by e.g. temp tables).
      We need to filter those substituted fields out.
    */
    if (real_pos->type() == Item::FIELD_ITEM &&
        !(real_pos != pos &&
          ((Item_ref *)pos)->ref_type() == Item_ref::AGGREGATE_REF))
    {
      Item_field *item;
      if (!(item= new (thd->mem_root) Item_field(thd, ((Item_field*) real_pos))))
	goto err;
      if (pos->type() == Item::REF_ITEM)
      {
        /* preserve the names of the ref when dereferncing */
        Item_ref *ref= (Item_ref *) pos;
        item->db_name= ref->db_name;
        item->table_name= ref->table_name;
        item->name= ref->name;
      }
      pos= item;
      if (item->field->flags & BLOB_FLAG)
      {
	if (!(pos= new (thd->mem_root) Item_copy_string(thd, pos)))
	  goto err;
       /*
         Item_copy_string::copy for function can call 
         Item_copy_string::val_int for blob via Item_ref.
         But if Item_copy_string::copy for blob isn't called before,
         it's value will be wrong
         so let's insert Item_copy_string for blobs in the beginning of 
         copy_funcs
         (to see full test case look at having.test, BUG #4358) 
       */
	if (param->copy_funcs.push_front(pos, thd->mem_root))
	  goto err;
      }
      else
      {
	/* 
	   set up save buffer and change result_field to point at 
	   saved value
	*/
	field= item->field;
	item->result_field=field->make_new_field(thd->mem_root,
                                                 field->table, 1);
        /*
          We need to allocate one extra byte for null handling and
          another extra byte to not get warnings from purify in
          Field_string::val_int
        */
	if (!(tmp= (uchar*) thd->alloc(field->pack_length()+2)))
	  goto err;
        if (copy)
        {
          DBUG_ASSERT (param->field_count > (uint) (copy - copy_start));
          copy->set(tmp, item->result_field);
          item->result_field->move_field(copy->to_ptr,copy->to_null_ptr,1);
#ifdef HAVE_valgrind
          copy->to_ptr[copy->from_length]= 0;
#endif
          copy++;
        }
      }
    }
    else if ((real_pos->type() == Item::FUNC_ITEM ||
	      real_pos->real_type() == Item::SUBSELECT_ITEM ||
	      real_pos->type() == Item::CACHE_ITEM ||
	      real_pos->type() == Item::COND_ITEM) &&
	     !real_pos->with_sum_func)
    {						// Save for send fields
      LEX_CSTRING real_name= pos->name;
      pos= real_pos;
      pos->name= real_name;
      /* TODO:
	 In most cases this result will be sent to the user.
	 This should be changed to use copy_int or copy_real depending
	 on how the value is to be used: In some cases this may be an
	 argument in a group function, like: IF(ISNULL(col),0,COUNT(*))
      */
      if (!(pos=new (thd->mem_root) Item_copy_string(thd, pos)))
	goto err;
      if (i < border)                           // HAVING, ORDER and GROUP BY
      {
        if (extra_funcs.push_back(pos, thd->mem_root))
          goto err;
      }
      else if (param->copy_funcs.push_back(pos, thd->mem_root))
	goto err;
    }
    res_all_fields.push_back(pos, thd->mem_root);
    ref_pointer_array[((i < border)? all_fields.elements-i-1 : i-border)]=
      pos;
  }
  param->copy_field_end= copy;

  for (i= 0; i < border; i++)
    itr++;
  itr.sublist(res_selected_fields, elements);
  /*
    Put elements from HAVING, ORDER BY and GROUP BY last to ensure that any
    reference used in these will resolve to a item that is already calculated
  */
  param->copy_funcs.append(&extra_funcs);

  DBUG_RETURN(0);

 err:
  if (copy)
    delete [] param->copy_field;			// This is never 0
  param->copy_field= 0;
err2:
  DBUG_RETURN(TRUE);
}

Project: server

int join_read_key2(THD *thd, JOIN_TAB *tab, TABLE *table, TABLE_REF *table_ref)
{
  int error;
  if (!table->file->inited)
  {
    error= table->file->ha_index_init(table_ref->key, tab ? tab->sorted : TRUE);
    if (unlikely(error))
    {
      (void) report_error(table, error);
      return 1;
    }
  }

  /*
    The following is needed when one makes ref (or eq_ref) access from row
    comparisons: one must call row->bring_value() to get the new values.
  */
  if (tab && tab->bush_children)
  {
    TABLE_LIST *emb_sj_nest= tab->bush_children->start->emb_sj_nest;
    emb_sj_nest->sj_subq_pred->left_expr->bring_value();
  }

  /* TODO: Why don't we do "Late NULLs Filtering" here? */

  if (cmp_buffer_with_ref(thd, table, table_ref) ||
      (table->status & (STATUS_GARBAGE | STATUS_NO_PARENT | STATUS_NULL_ROW)))
  {
    if (table_ref->key_err)
    {
      table->status=STATUS_NOT_FOUND;
      return -1;
    }
    /*
      Moving away from the current record. Unlock the row
      in the handler if it did not match the partial WHERE.
    */
    if (tab && tab->ref.has_record && tab->ref.use_count == 0)
    {
      tab->read_record.table->file->unlock_row();
      table_ref->has_record= FALSE;
    }
    error=table->file->ha_index_read_map(table->record[0],
                                  table_ref->key_buff,
                                  make_prev_keypart_map(table_ref->key_parts),
                                  HA_READ_KEY_EXACT);
    if (unlikely(error) &&
        error != HA_ERR_KEY_NOT_FOUND && error != HA_ERR_END_OF_FILE)
      return report_error(table, error);

    if (likely(!error))
    {
      table_ref->has_record= TRUE;
      table_ref->use_count= 1;
    }
  }
  else if (table->status == 0)
  {
    DBUG_ASSERT(table_ref->has_record);
    table_ref->use_count++;
  }
  table->null_row=0;
  return table->status ? -1 : 0;
}

Project: server

void JOIN_TAB::cleanup()
{
  DBUG_ENTER("JOIN_TAB::cleanup");
  
  DBUG_PRINT("enter", ("tab: %p  table %s.%s",
                       this,
                       (table ? table->s->db.str : "?"),
                       (table ? table->s->table_name.str : "?")));
  delete select;
  select= 0;
  delete quick;
  quick= 0;
  if (cache)
  {
    cache->free();
    cache= 0;
  }
  limit= 0;
  // Free select that was created for filesort outside of create_sort_index
  if (filesort && filesort->select && !filesort->own_select)
    delete filesort->select;
  delete filesort;
  filesort= NULL;
  /* Skip non-existing derived tables/views result tables */
  if (table &&
      (table->s->tmp_table != INTERNAL_TMP_TABLE || table->is_created()))
  {
    table->file->ha_end_keyread();
    table->file->ha_index_or_rnd_end();
  }
  if (table)
  {
    table->file->ha_end_keyread();
    if (type == JT_FT)
      table->file->ha_ft_end();
    else
      table->file->ha_index_or_rnd_end();
    preread_init_done= FALSE;
    if (table->pos_in_table_list && 
        table->pos_in_table_list->jtbm_subselect)
    {
      if (table->pos_in_table_list->jtbm_subselect->is_jtbm_const_tab)
      {
        /*
          Set this to NULL so that cleanup_empty_jtbm_semi_joins() doesn't
          attempt to make another free_tmp_table call.
        */
        table->pos_in_table_list->table= NULL;
        free_tmp_table(join->thd, table);
        table= NULL;
      }
      else
      {
        TABLE_LIST *tmp= table->pos_in_table_list;
        end_read_record(&read_record);
        tmp->jtbm_subselect->cleanup();
        /* 
          The above call freed the materializedd temptable. Set it to NULL so
          that we don't attempt to touch it if JOIN_TAB::cleanup() is invoked
          multiple times (it may be)
        */
        tmp->table= NULL;
        table= NULL;
      }
      DBUG_VOID_RETURN;
    }
    /*
      We need to reset this for next select
      (Tested in part_of_refkey)
    */
    table->reginfo.join_tab= 0;
  }
  end_read_record(&read_record);
  explain_plan= NULL;
  DBUG_VOID_RETURN;
}

Project: server

void JOIN::restore_query_plan(Join_plan_state *restore_from)
{
  DYNAMIC_ARRAY tmp_keyuse;
  tmp_keyuse= keyuse;
  keyuse= restore_from->keyuse;
  restore_from->keyuse= tmp_keyuse;

  for (uint i= 0; i < table_count; i++)
  {
    join_tab[i].keyuse= restore_from->join_tab_keyuse[i];
    join_tab[i].checked_keys= restore_from->join_tab_checked_keys[i];
  }

  memcpy((uchar*) best_positions, (uchar*) restore_from->best_positions,
         sizeof(POSITION) * (table_count + 1));
  /* Restore SJM nests */
  List_iterator<TABLE_LIST> it(select_lex->sj_nests);
  TABLE_LIST *tlist;
  SJ_MATERIALIZATION_INFO **p_info= restore_from->sj_mat_info;
  while ((tlist= it++))
  {
    tlist->sj_mat_info= *(p_info++);
  }
}

Project: server

JOIN::reoptimize(Item *added_where, table_map join_tables,
                 Join_plan_state *save_to)
{
  DYNAMIC_ARRAY added_keyuse;
  SARGABLE_PARAM *sargables= 0; /* Used only as a dummy parameter. */
  uint org_keyuse_elements;

  /* Re-run the REF optimizer to take into account the new conditions. */
  if (update_ref_and_keys(thd, &added_keyuse, join_tab, table_count, added_where,
                          ~outer_join, select_lex, &sargables))
  {
    delete_dynamic(&added_keyuse);
    return REOPT_ERROR;
  }

  if (!added_keyuse.elements)
  {
    delete_dynamic(&added_keyuse);
    return REOPT_OLD_PLAN;
  }

  if (save_to)
    save_query_plan(save_to);
  else
    reset_query_plan();

  if (!keyuse.buffer &&
      my_init_dynamic_array(&keyuse, sizeof(KEYUSE), 20, 64,
                            MYF(MY_THREAD_SPECIFIC)))
  {
    delete_dynamic(&added_keyuse);
    return REOPT_ERROR;
  }

  org_keyuse_elements= save_to ? save_to->keyuse.elements : keyuse.elements;
  allocate_dynamic(&keyuse, org_keyuse_elements + added_keyuse.elements);

  /* If needed, add the access methods from the original query plan. */
  if (save_to)
  {
    DBUG_ASSERT(!keyuse.elements);
    keyuse.elements= save_to->keyuse.elements;
    if (size_t e= keyuse.elements)
      memcpy(keyuse.buffer,
             save_to->keyuse.buffer, e * keyuse.size_of_element);
  }

  /* Add the new access methods to the keyuse array. */
  memcpy(keyuse.buffer + keyuse.elements * keyuse.size_of_element,
         added_keyuse.buffer,
         (size_t) added_keyuse.elements * added_keyuse.size_of_element);
  keyuse.elements+= added_keyuse.elements;
  /* added_keyuse contents is copied, and it is no longer needed. */
  delete_dynamic(&added_keyuse);

  if (sort_and_filter_keyuse(thd, &keyuse, true))
    return REOPT_ERROR;
  optimize_keyuse(this, &keyuse);

  if (optimize_semijoin_nests(this, join_tables))
    return REOPT_ERROR;

  /* Re-run the join optimizer to compute a new query plan. */
  if (choose_plan(this, join_tables))
    return REOPT_ERROR;

  return REOPT_NEW_PLAN;
}

Project: server

static void add_not_null_conds(JOIN *join)
{
  JOIN_TAB *tab;
  DBUG_ENTER("add_not_null_conds");
  
  for (tab= first_linear_tab(join, WITH_BUSH_ROOTS, WITHOUT_CONST_TABLES);
       tab; 
       tab= next_linear_tab(join, tab, WITH_BUSH_ROOTS))
  {
    if (tab->type == JT_REF || tab->type == JT_EQ_REF || 
        tab->type == JT_REF_OR_NULL)
    {
      for (uint keypart= 0; keypart < tab->ref.key_parts; keypart++)
      {
        if (tab->ref.null_rejecting & ((key_part_map)1 << keypart))
        {
          Item *item= tab->ref.items[keypart];
          Item *notnull;
          Item *real= item->real_item();
	  if (real->const_item() && real->type() != Item::FIELD_ITEM && 
              !real->is_expensive())
          {
            /*
              It could be constant instead of field after constant
              propagation.
            */
            continue;
          }
          DBUG_ASSERT(real->type() == Item::FIELD_ITEM);
          Item_field *not_null_item= (Item_field*)real;
          JOIN_TAB *referred_tab= not_null_item->field->table->reginfo.join_tab;
          /*
            For UPDATE queries such as:
            UPDATE t1 SET t1.f2=(SELECT MAX(t2.f4) FROM t2 WHERE t2.f3=t1.f1);
            not_null_item is the t1.f1, but it's referred_tab is 0.
          */
          if (!(notnull= new (join->thd->mem_root)
                Item_func_isnotnull(join->thd, item)))
            DBUG_VOID_RETURN;
          /*
            We need to do full fix_fields() call here in order to have correct
            notnull->const_item(). This is needed e.g. by test_quick_select 
            when it is called from make_join_select after this function is 
            called.
          */
          if (notnull->fix_fields(join->thd, &notnull))
            DBUG_VOID_RETURN;

          DBUG_EXECUTE("where",print_where(notnull,
                                            (referred_tab ?
                                            referred_tab->table->alias.c_ptr() :
                                            "outer_ref_cond"),
                                            QT_ORDINARY););
          if (!tab->first_inner)
          {
            COND *new_cond= (referred_tab && referred_tab->join == join) ?
                              referred_tab->select_cond :
                              join->outer_ref_cond;
            add_cond_and_fix(join->thd, &new_cond, notnull);
            if (referred_tab && referred_tab->join == join)
              referred_tab->set_select_cond(new_cond, __LINE__);
            else 
              join->outer_ref_cond= new_cond;
          }
          else
            add_cond_and_fix(join->thd, tab->first_inner->on_expr_ref, notnull);
        }
      }
    }
  }
  DBUG_VOID_RETURN;
}

Project: server

static COND* substitute_for_best_equal_field(THD *thd, JOIN_TAB *context_tab,
                                             COND *cond,
                                             COND_EQUAL *cond_equal,
                                             void *table_join_idx)
{
  Item_equal *item_equal;
  COND *org_cond= cond;                 // Return this in case of fatal error

  if (cond->type() == Item::COND_ITEM)
  {
    List<Item> *cond_list= ((Item_cond*) cond)->argument_list();

    bool and_level= ((Item_cond*) cond)->functype() ==
                      Item_func::COND_AND_FUNC;
    if (and_level)
    {
      cond_equal= &((Item_cond_and *) cond)->m_cond_equal;
      cond_list->disjoin((List<Item> *) &cond_equal->current_level);/* remove Item_equal objects from the AND. */

      List_iterator_fast<Item_equal> it(cond_equal->current_level);      
      while ((item_equal= it++))
      {
        item_equal->sort(&compare_fields_by_table_order, table_join_idx);
      }
    }
    
    List_iterator<Item> li(*cond_list);
    Item *item;
    while ((item= li++))
    {
      Item *new_item= substitute_for_best_equal_field(thd, context_tab,
                                                      item, cond_equal,
                                                      table_join_idx);
      /*
        This works OK with PS/SP re-execution as changes are made to
        the arguments of AND/OR items only
      */
      if (new_item && new_item != item)
        li.replace(new_item);
    }

    if (and_level)
    {
      COND *eq_cond= 0;
      List_iterator_fast<Item_equal> it(cond_equal->current_level);
      bool false_eq_cond= FALSE;
      while ((item_equal= it++))
      {
        eq_cond= eliminate_item_equal(thd, eq_cond, cond_equal->upper_levels,
                                      item_equal);
        if (!eq_cond)
	{
          eq_cond= 0;
          break;
        }
        else if (eq_cond->type() == Item::INT_ITEM && !eq_cond->val_bool()) 
	{
          /*
            This occurs when eliminate_item_equal() founds that cond is
            always false and substitutes it with Item_int 0.
            Due to this, value of item_equal will be 0, so just return it.
	  */
          cond= eq_cond;
          false_eq_cond= TRUE;
          break;
        }
      }
      if (eq_cond && !false_eq_cond)
      {
        /* Insert the generated equalities before all other conditions */
        if (eq_cond->type() == Item::COND_ITEM)
          ((Item_cond *) cond)->add_at_head(
                                  ((Item_cond *) eq_cond)->argument_list());
        else
	{
          if (cond_list->is_empty())
            cond= eq_cond;
          else
	  {
             /* Do not add an equality condition if it's always true */ 
             if (eq_cond->type() != Item::INT_ITEM &&
                 cond_list->push_front(eq_cond, thd->mem_root))
               eq_cond= 0;
          }
	}
      }
      if (!eq_cond)
      {
        /* 
          We are out of memory doing the transformation.
          This is a fatal error now. However we bail out by returning the
          original condition that we had before we started the transformation. 
	*/
	cond_list->append((List<Item> *) &cond_equal->current_level);
      }
    }	 
  }
  else if (cond->type() == Item::FUNC_ITEM && 
           ((Item_func*) cond)->functype() == Item_func::MULT_EQUAL_FUNC)
  {
    item_equal= (Item_equal *) cond;
    item_equal->sort(&compare_fields_by_table_order, table_join_idx);
    cond_equal= item_equal->upper_levels;
    if (cond_equal && cond_equal->current_level.head() == item_equal)
      cond_equal= cond_equal->upper_levels;
    cond= eliminate_item_equal(thd, 0, cond_equal, item_equal);
    return cond ? cond : org_cond;
  }
  else 
  {
    while (cond_equal)
    {
      List_iterator_fast<Item_equal> it(cond_equal->current_level);
      while((item_equal= it++))
      {
        REPLACE_EQUAL_FIELD_ARG arg= {item_equal, context_tab};
        if (!(cond= cond->transform(thd, &Item::replace_equal_field,
                                    (uchar *) &arg)))
          return 0;
      }
      cond_equal= cond_equal->upper_levels;
    }
  }
  return cond;
}

Project: server

setup_group(THD *thd, Ref_ptr_array ref_pointer_array, TABLE_LIST *tables,
	    List<Item> &fields, List<Item> &all_fields, ORDER *order,
	    bool *hidden_group_fields, bool from_window_spec)
{
  enum_parsing_place context_analysis_place=
                     thd->lex->current_select->context_analysis_place;
  *hidden_group_fields=0;
  ORDER *ord;

  if (!order)
    return 0;				/* Everything is ok */

  uint org_fields=all_fields.elements;

  thd->where="group statement";
  for (ord= order; ord; ord= ord->next)
  {
    if (find_order_in_list(thd, ref_pointer_array, tables, ord, fields,
                           all_fields, true, true, from_window_spec))
      return 1;
    (*ord->item)->marker= UNDEF_POS;		/* Mark found */
    if ((*ord->item)->with_sum_func && context_analysis_place == IN_GROUP_BY)
    {
      my_error(ER_WRONG_GROUP_FIELD, MYF(0), (*ord->item)->full_name());
      return 1;
    }
    if ((*ord->item)->with_window_func)
    {
      if (context_analysis_place == IN_GROUP_BY)
        my_error(ER_WRONG_PLACEMENT_OF_WINDOW_FUNCTION, MYF(0));
      else
        my_error(ER_WINDOW_FUNCTION_IN_WINDOW_SPEC, MYF(0));
      return 1;
    }
    if (from_window_spec && (*ord->item)->with_sum_func &&
        (*ord->item)->type() != Item::SUM_FUNC_ITEM)
      (*ord->item)->split_sum_func(thd, ref_pointer_array,
                                   all_fields, SPLIT_SUM_SELECT);
  }
  if (thd->variables.sql_mode & MODE_ONLY_FULL_GROUP_BY &&
      context_analysis_place == IN_GROUP_BY)
  {
    /*
      Don't allow one to use fields that is not used in GROUP BY
      For each select a list of field references that aren't under an
      aggregate function is created. Each field in this list keeps the
      position of the select list expression which it belongs to.

      First we check an expression from the select list against the GROUP BY
      list. If it's found there then it's ok. It's also ok if this expression
      is a constant or an aggregate function. Otherwise we scan the list
      of non-aggregated fields and if we'll find at least one field reference
      that belongs to this expression and doesn't occur in the GROUP BY list
      we throw an error. If there are no fields in the created list for a
      select list expression this means that all fields in it are used under
      aggregate functions.
    */
    Item *item;
    Item_field *field;
    int cur_pos_in_select_list= 0;
    List_iterator<Item> li(fields);
    List_iterator<Item_field> naf_it(thd->lex->current_select->join->non_agg_fields);

    field= naf_it++;
    while (field && (item=li++))
    {
      if (item->type() != Item::SUM_FUNC_ITEM && item->marker >= 0 &&
          !item->const_item() &&
          !(item->real_item()->type() == Item::FIELD_ITEM &&
            item->used_tables() & OUTER_REF_TABLE_BIT))
      {
        while (field)
        {
          /* Skip fields from previous expressions. */
          if (field->marker < cur_pos_in_select_list)
            goto next_field;
          /* Found a field from the next expression. */
          if (field->marker > cur_pos_in_select_list)
            break;
          /*
            Check whether the field occur in the GROUP BY list.
            Throw the error later if the field isn't found.
          */
          for (ord= order; ord; ord= ord->next)
            if ((*ord->item)->eq((Item*)field, 0))
              goto next_field;
          /*
            TODO: change ER_WRONG_FIELD_WITH_GROUP to more detailed
            ER_NON_GROUPING_FIELD_USED
          */
          my_error(ER_WRONG_FIELD_WITH_GROUP, MYF(0), field->full_name());
          return 1;
next_field:
          field= naf_it++;
        }
      }
      cur_pos_in_select_list++;
    }
  }
  if (org_fields != all_fields.elements)
    *hidden_group_fields=1;			// group fields is not used
  return 0;
}

Project: server

bool skip_setup_conds(THD *thd)
{
  return (!thd->stmt_arena->is_conventional()
          && !thd->stmt_arena->is_stmt_prepare_or_first_sp_execute())
         || thd->lex->is_view_context_analysis();
}

Project: server

void rr_unlock_row(st_join_table *tab)
{
  READ_RECORD *info= &tab->read_record;
  info->table->file->unlock_row();
}

Project: server

remove_const(JOIN *join,ORDER *first_order, COND *cond,
             bool change_list, bool *simple_order)
{
  *simple_order= join->rollup.state == ROLLUP::STATE_NONE;
  if (join->only_const_tables())
    return change_list ? 0 : first_order;		// No need to sort

  ORDER *order,**prev_ptr, *tmp_order;
  table_map UNINIT_VAR(first_table); /* protected by first_is_base_table */
  table_map not_const_tables= ~join->const_table_map;
  table_map ref;
  bool first_is_base_table= FALSE;
  DBUG_ENTER("remove_const");
  
  /*
    Join tab is set after make_join_statistics() has been called.
    In case of one table with GROUP BY this function is called before
    join_tab is set for the GROUP_BY expression
  */
  if (join->join_tab)
  {
    if (join->join_tab[join->const_tables].table)
    {
      first_table= join->join_tab[join->const_tables].table->map;
      first_is_base_table= TRUE;
    }
  
    /*
      Cleanup to avoid interference of calls of this function for
      ORDER BY and GROUP BY
    */
    for (JOIN_TAB *tab= join->join_tab + join->const_tables;
         tab < join->join_tab + join->table_count;
         tab++)
      tab->cached_eq_ref_table= FALSE;

    *simple_order= *join->join_tab[join->const_tables].on_expr_ref ? 0 : 1;
  }
  else
  {
    first_is_base_table= FALSE;
    first_table= 0;                     // Not used, for gcc
  }

  prev_ptr= &first_order;

  /* NOTE: A variable of not_const_tables ^ first_table; breaks gcc 2.7 */

  update_depend_map_for_order(join, first_order);
  for (order=first_order; order ; order=order->next)
  {
    table_map order_tables=order->item[0]->used_tables();
    if (order->item[0]->with_sum_func ||
        order->item[0]->with_window_func ||
        /*
          If the outer table of an outer join is const (either by itself or
          after applying WHERE condition), grouping on a field from such a
          table will be optimized away and filesort without temporary table
          will be used unless we prevent that now. Filesort is not fit to
          handle joins and the join condition is not applied. We can't detect
          the case without an expensive test, however, so we force temporary
          table for all queries containing more than one table, ROLLUP, and an
          outer join.
         */
        (join->table_count > 1 && join->rollup.state == ROLLUP::STATE_INITED &&
        join->outer_join))
      *simple_order=0;				// Must do a temp table to sort
    else if (!(order_tables & not_const_tables))
    {
      if (order->item[0]->with_subquery())
      {
        /*
          Delay the evaluation of constant ORDER and/or GROUP expressions that
          contain subqueries until the execution phase.
        */
        join->exec_const_order_group_cond.push_back(order->item[0],
                                                    join->thd->mem_root);
      }
      DBUG_PRINT("info",("removing: %s", order->item[0]->full_name()));
      continue;
    }
    else
    {
      if (order_tables & (RAND_TABLE_BIT | OUTER_REF_TABLE_BIT))
	*simple_order=0;
      else
      {
	if (cond && const_expression_in_where(cond,order->item[0]))
	{
	  DBUG_PRINT("info",("removing: %s", order->item[0]->full_name()));
	  continue;
	}
	if (first_is_base_table &&
            (ref=order_tables & (not_const_tables ^ first_table)))
	{
	  if (!(order_tables & first_table) &&
              only_eq_ref_tables(join,first_order, ref))
	  {
	    DBUG_PRINT("info",("removing: %s", order->item[0]->full_name()));
	    continue;
	  }
          /*
            UseMultipleEqualitiesToRemoveTempTable:
            Can use multiple-equalities here to check that ORDER BY columns
            can be used without tmp. table.
          */
          bool can_subst_to_first_table= false;
          bool first_is_in_sjm_nest= false;
          if (first_is_base_table)
          {
            TABLE_LIST *tbl_for_first=
              join->join_tab[join->const_tables].table->pos_in_table_list;
            first_is_in_sjm_nest= tbl_for_first->sj_mat_info &&
                                  tbl_for_first->sj_mat_info->is_used;
          }
          /*
            Currently we do not employ the optimization that uses multiple
            equalities for ORDER BY to remove tmp table in the case when
            the first table happens to be the result of materialization of
            a semi-join nest ( <=> first_is_in_sjm_nest == true).

            When a semi-join nest is materialized and scanned to look for
            possible matches in the remaining tables for every its row
            the fields from the result of materialization are copied
            into the record buffers of tables from the semi-join nest.
            So these copies are used to access the remaining tables rather
            than the fields from the result of materialization.

            Unfortunately now this so-called 'copy back' technique is
            supported only if the rows  are scanned with the rr_sequential
            function, but not with other rr_* functions that are employed
            when the result of materialization is required to be sorted.

            TODO: either to support 'copy back' technique for the above case,
                  or to get rid of this technique altogether.
          */
          if (optimizer_flag(join->thd, OPTIMIZER_SWITCH_ORDERBY_EQ_PROP) &&
              first_is_base_table && !first_is_in_sjm_nest &&
              order->item[0]->real_item()->type() == Item::FIELD_ITEM &&
              join->cond_equal)
          {
            table_map first_table_bit=
              join->join_tab[join->const_tables].table->map;

            Item *item= order->item[0];

            /*
              TODO: equality substitution in the context of ORDER BY is 
              sometimes allowed when it is not allowed in the general case.
              
              We make the below call for its side effect: it will locate the
              multiple equality the item belongs to and set item->item_equal
              accordingly.
            */
            Item *res= item->propagate_equal_fields(join->thd,
                                                    Value_source::
                                                    Context_identity(),
                                                    join->cond_equal);
            Item_equal *item_eq;
            if ((item_eq= res->get_item_equal()))
            {
              Item *first= item_eq->get_first(NO_PARTICULAR_TAB, NULL);
              if (first->const_item() || first->used_tables() ==
                                         first_table_bit)
              {
                can_subst_to_first_table= true;
              }
            }
          }

          if (!can_subst_to_first_table)
          {
            *simple_order=0;			// Must do a temp table to sort
          }
	}
      }
    }
    /* Remove ORDER BY entries that we have seen before */
    for (tmp_order= first_order;
         tmp_order != order;
         tmp_order= tmp_order->next)
    {
      if (tmp_order->item[0]->eq(order->item[0],1))
        break;
    }
    if (tmp_order != order)
      continue;                                // Duplicate order by. Remove
    
    if (change_list)
      *prev_ptr= order;				// use this entry
    prev_ptr= &order->next;
  }
  if (change_list)
    *prev_ptr=0;
  if (prev_ptr == &first_order)			// Nothing to sort/group
    *simple_order=1;
#ifndef DBUG_OFF
  if (unlikely(join->thd->is_error()))
    DBUG_PRINT("error",("Error from remove_const"));
#endif
  DBUG_PRINT("exit",("simple_order: %d",(int) *simple_order));
  DBUG_RETURN(first_order);
}

Project: server

static bool check_simple_equality(THD *thd, const Item::Context &ctx,
                                  Item *left_item, Item *right_item,
                                  COND_EQUAL *cond_equal)
{
  Item *orig_left_item= left_item;
  Item *orig_right_item= right_item;
  if (left_item->type() == Item::REF_ITEM &&
      ((Item_ref*)left_item)->ref_type() == Item_ref::VIEW_REF)
  {
    if (((Item_ref*)left_item)->get_depended_from())
      return FALSE;
    if (((Item_direct_view_ref*)left_item)->get_null_ref_table() !=
        NO_NULL_TABLE && !left_item->real_item()->used_tables())
      return FALSE;
    left_item= left_item->real_item();
  }
  if (right_item->type() == Item::REF_ITEM &&
      ((Item_ref*)right_item)->ref_type() == Item_ref::VIEW_REF)
  {
    if (((Item_ref*)right_item)->get_depended_from())
      return FALSE;
    if (((Item_direct_view_ref*)right_item)->get_null_ref_table() !=
        NO_NULL_TABLE && !right_item->real_item()->used_tables())
      return FALSE;
    right_item= right_item->real_item();
  }
  if (left_item->type() == Item::FIELD_ITEM &&
      right_item->type() == Item::FIELD_ITEM &&
      !((Item_field*)left_item)->get_depended_from() &&
      !((Item_field*)right_item)->get_depended_from())
  {
    /* The predicate the form field1=field2 is processed */

    Field *left_field= ((Item_field*) left_item)->field;
    Field *right_field= ((Item_field*) right_item)->field;

    if (!left_field->eq_def(right_field))
      return FALSE;

    /* Search for multiple equalities containing field1 and/or field2 */
    bool left_copyfl, right_copyfl;
    Item_equal *left_item_equal=
               find_item_equal(cond_equal, left_field, &left_copyfl);
    Item_equal *right_item_equal= 
               find_item_equal(cond_equal, right_field, &right_copyfl);

    /* As (NULL=NULL) != TRUE we can't just remove the predicate f=f */
    if (left_field->eq(right_field)) /* f = f */
      return (!(left_field->maybe_null() && !left_item_equal)); 

    if (left_item_equal && left_item_equal == right_item_equal)
    {
      /* 
        The equality predicate is inference of one of the existing
        multiple equalities, i.e the condition is already covered
        by upper level equalities
      */
       return TRUE;
    }
      
    /* Copy the found multiple equalities at the current level if needed */
    if (left_copyfl)
    {
      /* left_item_equal of an upper level contains left_item */
      left_item_equal= new (thd->mem_root) Item_equal(thd, left_item_equal);
      left_item_equal->set_context_field(((Item_field*) left_item));
      cond_equal->current_level.push_back(left_item_equal, thd->mem_root);
    }
    if (right_copyfl)
    {
      /* right_item_equal of an upper level contains right_item */
      right_item_equal= new (thd->mem_root) Item_equal(thd, right_item_equal);
      right_item_equal->set_context_field(((Item_field*) right_item));
      cond_equal->current_level.push_back(right_item_equal, thd->mem_root);
    }

    if (left_item_equal)
    { 
      /* left item was found in the current or one of the upper levels */
      if (! right_item_equal)
        left_item_equal->add(orig_right_item, thd->mem_root);
      else
      {
        /* Merge two multiple equalities forming a new one */
        left_item_equal->merge(thd, right_item_equal);
        /* Remove the merged multiple equality from the list */
        List_iterator<Item_equal> li(cond_equal->current_level);
        while ((li++) != right_item_equal) ;
        li.remove();
      }
    }
    else
    { 
      /* left item was not found neither the current nor in upper levels  */
      if (right_item_equal)
        right_item_equal->add(orig_left_item, thd->mem_root);
      else 
      {
        /* None of the fields was found in multiple equalities */
        Type_handler_hybrid_field_type
          tmp(orig_left_item->type_handler_for_comparison());
        if (tmp.aggregate_for_comparison(orig_right_item->
                                         type_handler_for_comparison()))
          return false;
        Item_equal *item_equal=
          new (thd->mem_root) Item_equal(thd, tmp.type_handler(),
                                         orig_left_item, orig_right_item,
                                         false);
        item_equal->set_context_field((Item_field*)left_item);
        cond_equal->current_level.push_back(item_equal, thd->mem_root);
      }
    }
    return TRUE;
  }

  {
    /* The predicate of the form field=const/const=field is processed */
    Item *const_item= 0;
    Item_field *field_item= 0;
    Item *orig_field_item= 0;
    if (left_item->type() == Item::FIELD_ITEM &&
        !((Item_field*)left_item)->get_depended_from() &&
        right_item->const_item() && !right_item->is_expensive())
    {
      orig_field_item= orig_left_item;
      field_item= (Item_field *) left_item;
      const_item= right_item;
    }
    else if (right_item->type() == Item::FIELD_ITEM &&
             !((Item_field*)right_item)->get_depended_from() &&
             left_item->const_item() && !left_item->is_expensive())
    {
      orig_field_item= orig_right_item;
      field_item= (Item_field *) right_item;
      const_item= left_item;
    }

    if (const_item &&
        field_item->field->test_if_equality_guarantees_uniqueness(const_item))
    {
      /*
        field_item and const_item are arguments of a scalar or a row
        comparison function:
          WHERE column=constant
          WHERE (column, ...) = (constant, ...)

        The owner comparison function has previously called fix_fields(),
        so field_item and const_item should be directly comparable items,
        field_item->cmp_context and const_item->cmp_context should be set.
        In case of string comparison, charsets and collations of
        field_item and const_item should have already be aggregated
        for comparison, all necessary character set converters installed
        and fixed.

        In case of string comparison, const_item can be either:
        - a weaker constant that does not need to be converted to field_item:
            WHERE latin1_field = 'latin1_const'
            WHERE varbinary_field = 'latin1_const'
            WHERE latin1_bin_field = 'latin1_general_ci_const'
        - a stronger constant that does not need to be converted to field_item:
            WHERE latin1_field = binary 0xDF
            WHERE latin1_field = 'a' COLLATE latin1_bin
        - a result of conversion (e.g. from the session character set)
          to the character set of field_item:
            WHERE latin1_field = 'utf8_string_with_latin1_repertoire'
      */
      bool copyfl;

      Item_equal *item_equal = find_item_equal(cond_equal,
                                               field_item->field, &copyfl);
      if (copyfl)
      {
        item_equal= new (thd->mem_root) Item_equal(thd, item_equal);
        cond_equal->current_level.push_back(item_equal, thd->mem_root);
        item_equal->set_context_field(field_item);
      }
      Item *const_item2= field_item->field->get_equal_const_item(thd, ctx,
                                                                 const_item);
      if (!const_item2)
        return false;

      if (item_equal)
      {
        /* 
          The flag cond_false will be set to 1 after this, if item_equal
          already contains a constant and its value is  not equal to
          the value of const_item.
        */
        item_equal->add_const(thd, const_item2);
      }
      else
      {
        Type_handler_hybrid_field_type
          tmp(orig_left_item->type_handler_for_comparison());
        if (tmp.aggregate_for_comparison(orig_right_item->
                                         type_handler_for_comparison()))
          return false;
        item_equal= new (thd->mem_root) Item_equal(thd, tmp.type_handler(),
                                                   const_item2,
                                                   orig_field_item, true);
        item_equal->set_context_field(field_item);
        cond_equal->current_level.push_back(item_equal, thd->mem_root);
      }
      return TRUE;
    }
  }
  return FALSE;
}

Project: server

bool TABLE_LIST::is_active_sjm()
{ 
  return sj_mat_info && sj_mat_info->is_used;
}

Project: server

static bool prepare_sum_aggregators(Item_sum **func_ptr, bool need_distinct)
{
  Item_sum *func;
  DBUG_ENTER("prepare_sum_aggregators");
  while ((func= *(func_ptr++)))
  {
    if (func->set_aggregator(need_distinct && func->has_with_distinct() ?
                             Aggregator::DISTINCT_AGGREGATOR :
                             Aggregator::SIMPLE_AGGREGATOR))
      DBUG_RETURN(TRUE);
  }
  DBUG_RETURN(FALSE);
}

Project: server

bool Virtual_tmp_table::sp_find_field_by_name(uint *idx,
                                              const LEX_CSTRING &name) const
{
  Field *f;
  for (uint i= 0; (f= field[i]); i++)
  {
    // Use the same comparison style with sp_context::find_variable()
    if (!my_strnncoll(system_charset_info,
                      (const uchar *) f->field_name.str,
                      f->field_name.length,
                      (const uchar *) name.str, name.length))
    {
      *idx= i;
      return false;
    }
  }
  return true;
}

Project: server

AGGR_OP::prepare_tmp_table()
{
  TABLE *table= join_tab->table;
  JOIN *join= join_tab->join;
  int rc= 0;

  if (!join_tab->table->is_created())
  {
    if (instantiate_tmp_table(table, join_tab->tmp_table_param->keyinfo,
                              join_tab->tmp_table_param->start_recinfo,
                              &join_tab->tmp_table_param->recinfo,
                              join->select_options))
      return true;
    (void) table->file->extra(HA_EXTRA_WRITE_CACHE);
  }
  /* If it wasn't already, start index scan for grouping using table index. */
  if (!table->file->inited && table->group &&
      join_tab->tmp_table_param->sum_func_count && table->s->keys)
    rc= table->file->ha_index_init(0, 0);
  else
  {
    /* Start index scan in scanning mode */
    rc= table->file->ha_rnd_init(true);
  }
  if (rc)
  {
    table->file->print_error(rc, MYF(0));
    return true;
  }
  return false;
}

Project: server

void JOIN::get_prefix_cost_and_fanout(uint n_tables, 
                                      double *read_time_arg,
                                      double *record_count_arg)
{
  double record_count= 1;
  double read_time= 0.0;
  for (uint i= const_tables; i < n_tables + const_tables ; i++)
  {
    if (best_positions[i].records_read)
    {
      record_count= COST_MULT(record_count, best_positions[i].records_read);
      read_time= COST_ADD(read_time, best_positions[i].read_time);
    }
    /* TODO: Take into account condition selectivities here */
  }
  *read_time_arg= read_time;// + record_count / TIME_FOR_COMPARE;
  *record_count_arg= record_count;
}

Project: server

static void add_key_fields_for_nj(JOIN *join, TABLE_LIST *nested_join_table,
                                  KEY_FIELD **end, uint *and_level,
                                  SARGABLE_PARAM **sargables)
{
  List_iterator<TABLE_LIST> li(nested_join_table->nested_join->join_list);
  List_iterator<TABLE_LIST> li2(nested_join_table->nested_join->join_list);
  bool have_another = FALSE;
  table_map tables= 0;
  TABLE_LIST *table;
  DBUG_ASSERT(nested_join_table->nested_join);

  while ((table= li++) || (have_another && (li=li2, have_another=FALSE,
                                            (table= li++))))
  {
    if (table->nested_join)
    {
      if (!table->on_expr)
      {
        /* It's a semi-join nest. Walk into it as if it wasn't a nest */
        have_another= TRUE;
        li2= li;
        li= List_iterator<TABLE_LIST>(table->nested_join->join_list); 
      }
      else
        add_key_fields_for_nj(join, table, end, and_level, sargables);
    }
    else
      if (!table->on_expr)
        tables |= table->table->map;
  }
  if (nested_join_table->on_expr)
    nested_join_table->on_expr->add_key_fields(join, end, and_level, tables,
                                               sargables);
}

Project: server

bool vers_select_conds_t::init_from_sysvar(THD *thd)
{
  vers_asof_timestamp_t &in= thd->variables.vers_asof_timestamp;
  type= (vers_system_time_t) in.type;
  delete_history= false;
  start.unit= VERS_TIMESTAMP;
  if (type != SYSTEM_TIME_UNSPECIFIED && type != SYSTEM_TIME_ALL)
  {
    DBUG_ASSERT(type == SYSTEM_TIME_AS_OF);
    MYSQL_TIME ltime;
    thd->variables.time_zone->gmt_sec_to_TIME(&ltime, in.unix_time);
    ltime.second_part = in.second_part;

    start.item= new (thd->mem_root)
        Item_datetime_literal(thd, &ltime, TIME_SECOND_PART_DIGITS);
    if (!start.item)
      return true;
  }
  else
    start.item= NULL;
  end.empty();
  return false;
}

Project: server

COND *Item_cond::build_equal_items(THD *thd,
                                   COND_EQUAL *inherited,
                                   bool link_item_fields,
                                   COND_EQUAL **cond_equal_ref)
{
  List<Item> *cond_args= argument_list();
  
  List_iterator<Item> li(*cond_args);
  Item *item;

  DBUG_ASSERT(!cond_equal_ref || !cond_equal_ref[0]);
  /*
     Make replacement of equality predicates for lower levels
     of the condition expression.
     Update used_tables_cache and const_item_cache on the way.
  */
  used_tables_and_const_cache_init();
  while ((item= li++))
  { 
    Item *new_item;
    if ((new_item= item->build_equal_items(thd, inherited, false, NULL))
        != item)
    {
      /* This replacement happens only for standalone equalities */
      /*
        This is ok with PS/SP as the replacement is done for
        arguments of an AND/OR item, which are restored for each
        execution of PS/SP.
      */
      li.replace(new_item);
    }
    used_tables_and_const_cache_join(new_item);
  }
  return this;
}

Project: server

make_cond_for_table_from_pred(THD *thd, Item *root_cond, Item *cond,
                              table_map tables, table_map used_table,
                              int join_tab_idx_arg,
                              bool exclude_expensive_cond __attribute__
                              ((unused)),
                              bool retain_ref_cond,
                              bool is_top_and_level)

{
  table_map rand_table_bit= (table_map) RAND_TABLE_BIT;

  if (used_table && !(cond->used_tables() & used_table))
    return (COND*) 0;				// Already checked

  if (cond->type() == Item::COND_ITEM)
  {
    if (((Item_cond*) cond)->functype() == Item_func::COND_AND_FUNC)
    {
      /* Create new top level AND item */
      Item_cond_and *new_cond=new (thd->mem_root) Item_cond_and(thd);
      if (!new_cond)
	return (COND*) 0;			// OOM /* purecov: inspected */
      List_iterator<Item> li(*((Item_cond*) cond)->argument_list());
      Item *item;
      while ((item=li++))
      {
        /*
          Special handling of top level conjuncts with RAND_TABLE_BIT:
          if such a conjunct contains a reference to a field that is not
          an outer field then it is pushed to the corresponding table by
          the same rule as all other conjuncts. Otherwise, if the conjunct
          is used in WHERE is is pushed to the last joined table, if is it
          is used in ON condition of an outer join it is pushed into the
          last inner table of the outer join. Such conjuncts are pushed in
          a call of make_cond_for_table_from_pred() with the
          parameter 'used_table' equal to PSEUDO_TABLE_BITS.
        */
        if (is_top_and_level && used_table == rand_table_bit &&
            (item->used_tables() & ~OUTER_REF_TABLE_BIT) != rand_table_bit)
        {
          /* The conjunct with RAND_TABLE_BIT has been allready pushed */
          continue;
        }
	Item *fix=make_cond_for_table_from_pred(thd, root_cond, item, 
                                                tables, used_table,
                                                join_tab_idx_arg,
                                                exclude_expensive_cond,
                                                retain_ref_cond, false);
	if (fix)
	  new_cond->argument_list()->push_back(fix, thd->mem_root);
      }
      switch (new_cond->argument_list()->elements) {
      case 0:
	return (COND*) 0;			// Always true
      case 1:
	return new_cond->argument_list()->head();
      default:
	/*
          Call fix_fields to propagate all properties of the children to
          the new parent Item. This should not be expensive because all
	  children of Item_cond_and should be fixed by now.
	*/
	if (new_cond->fix_fields(thd, 0))
          return (COND*) 0;
	new_cond->used_tables_cache=
	  ((Item_cond_and*) cond)->used_tables_cache &
	  tables;
	return new_cond;
      }
    }
    else
    {						// Or list
      if (is_top_and_level && used_table == rand_table_bit &&
          (cond->used_tables() & ~OUTER_REF_TABLE_BIT) != rand_table_bit)
      {
        /* This top level formula with RAND_TABLE_BIT has been already pushed */
        return (COND*) 0;
      }

      Item_cond_or *new_cond=new (thd->mem_root) Item_cond_or(thd);
      if (!new_cond)
	return (COND*) 0;			// OOM /* purecov: inspected */
      List_iterator<Item> li(*((Item_cond*) cond)->argument_list());
      Item *item;
      while ((item=li++))
      {
	Item *fix=make_cond_for_table_from_pred(thd, root_cond, item,
                                                tables, 0L,
                                                join_tab_idx_arg,
                                                exclude_expensive_cond,
                                                retain_ref_cond, false);
	if (!fix)
	  return (COND*) 0;			// Always true
	new_cond->argument_list()->push_back(fix, thd->mem_root);
      }
      /*
        Call fix_fields to propagate all properties of the children to
        the new parent Item. This should not be expensive because all
        children of Item_cond_and should be fixed by now.
      */
      new_cond->fix_fields(thd, 0);
      new_cond->used_tables_cache= ((Item_cond_or*) cond)->used_tables_cache;
      new_cond->top_level_item();
      return new_cond;
    }
  }

  if (is_top_and_level && used_table == rand_table_bit &&
      (cond->used_tables() & ~OUTER_REF_TABLE_BIT) != rand_table_bit)
  {
    /* This top level formula with RAND_TABLE_BIT has been already pushed */
    return (COND*) 0;
  }

  /*
    Because the following test takes a while and it can be done
    table_count times, we mark each item that we have examined with the result
    of the test
  */
  if ((cond->marker == 3 && !retain_ref_cond) ||
      (cond->used_tables() & ~tables))
    return (COND*) 0;				// Can't check this yet

  if (cond->marker == 2 || cond->eq_cmp_result() == Item::COND_OK)
  {
    cond->set_join_tab_idx(join_tab_idx_arg);
    return cond;				// Not boolean op
  }

  if (cond->type() == Item::FUNC_ITEM && 
      ((Item_func*) cond)->functype() == Item_func::EQ_FUNC)
  {
    Item *left_item=	((Item_func*) cond)->arguments()[0]->real_item();
    Item *right_item= ((Item_func*) cond)->arguments()[1]->real_item();
    if (left_item->type() == Item::FIELD_ITEM && !retain_ref_cond &&
	test_if_ref(root_cond, (Item_field*) left_item,right_item))
    {
      cond->marker=3;			// Checked when read
      return (COND*) 0;
    }
    if (right_item->type() == Item::FIELD_ITEM && !retain_ref_cond &&
	test_if_ref(root_cond, (Item_field*) right_item,left_item))
    {
      cond->marker=3;			// Checked when read
      return (COND*) 0;
    }
    /*
      If cond is an equality injected for split optimization then
      a. when retain_ref_cond == false : cond is removed unconditionally
         (cond that supports ref access is removed by the preceding code)
      b. when retain_ref_cond == true : cond is removed if it does not
         support ref access
    */
    if (left_item->type() == Item::FIELD_ITEM &&
        is_eq_cond_injected_for_split_opt((Item_func_eq *) cond) &&
        (!retain_ref_cond ||
         !test_if_ref(root_cond, (Item_field*) left_item,right_item)))
    {
      cond->marker=3;
      return (COND*) 0;
    }
  }
  cond->marker=2;
  cond->set_join_tab_idx(join_tab_idx_arg);
  return cond;
}

Project: server

bool TABLE_REF::is_access_triggered()
{
  for (uint i = 0; i < key_parts; i++)
  {
    if (cond_guards[i])
      return TRUE;
  }
  return FALSE;
}

Project: server

bool JOIN_TAB::save_explain_data(Explain_table_access *eta,
                                 table_map prefix_tables, 
                                 bool distinct_arg, JOIN_TAB *first_top_tab)
{
  int quick_type;
  CHARSET_INFO *cs= system_charset_info;
  THD *thd=      join->thd;
  TABLE_LIST *table_list= table->pos_in_table_list;
  QUICK_SELECT_I *cur_quick= NULL;
  my_bool key_read;
  char table_name_buffer[SAFE_NAME_LEN];
  KEY *key_info= 0;
  uint key_len= 0;
  quick_type= -1;

  explain_plan= eta;
  eta->key.clear();
  eta->quick_info= NULL;

  SQL_SELECT *tab_select;
  /* 
    We assume that if this table does pre-sorting, then it doesn't do filtering
    with SQL_SELECT.
  */
  DBUG_ASSERT(!(select && filesort));
  tab_select= (filesort)? filesort->select : select;

  if (filesort)
  {
    if (!(eta->pre_join_sort=
          new (thd->mem_root) Explain_aggr_filesort(thd->mem_root,
                                                    thd->lex->analyze_stmt,
                                                    filesort)))
      return 1;
  }
  
  tracker= &eta->tracker;
  jbuf_tracker= &eta->jbuf_tracker;

  /* Enable the table access time tracker only for "ANALYZE stmt" */
  if (thd->lex->analyze_stmt)
    table->file->set_time_tracker(&eta->op_tracker);

  /* No need to save id and select_type here, they are kept in Explain_select */

  /* table */
  if (table->derived_select_number)
  {
    /* Derived table name generation */
    size_t len= my_snprintf(table_name_buffer, sizeof(table_name_buffer)-1,
                         "<derived%u>",
                         table->derived_select_number);
    eta->table_name.copy(table_name_buffer, len, cs);
  }
  else if (bush_children)
  {
    JOIN_TAB *ctab= bush_children->start;
    /* table */
    size_t len= my_snprintf(table_name_buffer,
                         sizeof(table_name_buffer)-1,
                         "<subquery%d>", 
                         ctab->emb_sj_nest->sj_subq_pred->get_identifier());
    eta->table_name.copy(table_name_buffer, len, cs);
  }
  else
  {
    TABLE_LIST *real_table= table->pos_in_table_list;
    /*
      When multi-table UPDATE/DELETE does updates/deletes to a VIEW, the view
      is merged in a certain particular way (grep for DT_MERGE_FOR_INSERT).

      As a result, view's underlying tables have $tbl->pos_in_table_list={view}.
      We don't want to print view name in EXPLAIN, we want underlying table's
      alias (like specified in the view definition).
    */
    if (real_table->merged_for_insert)
    {
      TABLE_LIST *view_child= real_table->view->select_lex.table_list.first;
      for (;view_child; view_child= view_child->next_local)
      {
        if (view_child->table == table)
        {
          real_table= view_child;
          break;
        }
      }
    }
    eta->table_name.copy(real_table->alias.str, real_table->alias.length, cs);
  }

  /* "partitions" column */
  {
#ifdef WITH_PARTITION_STORAGE_ENGINE
    partition_info *part_info;
    if (!table->derived_select_number && 
        (part_info= table->part_info))
    { //TODO: all thd->mem_root here should be fixed
      make_used_partitions_str(thd->mem_root, part_info, &eta->used_partitions,
                               eta->used_partitions_list);
      eta->used_partitions_set= true;
    }
    else
      eta->used_partitions_set= false;
#else
    /* just produce empty column if partitioning is not compiled in */
    eta->used_partitions_set= false;
#endif
  }

  /* "type" column */
  enum join_type tab_type= type;
  if ((type == JT_ALL || type == JT_HASH) &&
       tab_select && tab_select->quick && use_quick != 2)
  {
    cur_quick= tab_select->quick;
    quick_type= cur_quick->get_type();
    if ((quick_type == QUICK_SELECT_I::QS_TYPE_INDEX_MERGE) ||
        (quick_type == QUICK_SELECT_I::QS_TYPE_INDEX_INTERSECT) ||
        (quick_type == QUICK_SELECT_I::QS_TYPE_ROR_INTERSECT) ||
        (quick_type == QUICK_SELECT_I::QS_TYPE_ROR_UNION))
      tab_type= type == JT_ALL ? JT_INDEX_MERGE : JT_HASH_INDEX_MERGE;
    else
      tab_type= type == JT_ALL ? JT_RANGE : JT_HASH_RANGE;
  }
  eta->type= tab_type;

  /* Build "possible_keys" value */
  // psergey-todo: why does this use thd MEM_ROOT??? Doesn't this 
  // break ANALYZE ? thd->mem_root will be freed, and after that we will
  // attempt to print the query plan?
  if (append_possible_keys(thd->mem_root, eta->possible_keys, table, keys))
    return 1;
  // psergey-todo: ^ check for error return code 

  /* Build "key", "key_len", and "ref" */
  if (tab_type == JT_NEXT)
  {
    key_info= table->key_info+index;
    key_len= key_info->key_length;
  }
  else if (ref.key_parts)
  {
    key_info= get_keyinfo_by_key_no(ref.key);
    key_len= ref.key_length;
  }
  
  /*
    In STRAIGHT_JOIN queries, there can be join tabs with JT_CONST type
    that still have quick selects.
  */
  if (tab_select && tab_select->quick && tab_type != JT_CONST)
  {
    if (!(eta->quick_info= tab_select->quick->get_explain(thd->mem_root)))
      return 1;
  }

  if (key_info) /* 'index' or 'ref' access */
  {
    eta->key.set(thd->mem_root, key_info, key_len);

    if (ref.key_parts && tab_type != JT_FT)
    {
      store_key **key_ref= ref.key_copy;
      for (uint kp= 0; kp < ref.key_parts; kp++)
      {
        if ((key_part_map(1) << kp) & ref.const_ref_part_map)
        {
          if (!(eta->ref_list.append_str(thd->mem_root, "const")))
            return 1;
          /*
            create_ref_for_key() handles keypart=const equalities as follows:
              - non-EXPLAIN execution will copy the "const" to lookup tuple
                immediately and will not add an element to ref.key_copy
              - EXPLAIN will put an element into ref.key_copy. Since we've
                just printed "const" for it, we should skip it here
          */
          if (thd->lex->describe)
            key_ref++;
        }
        else
        {
          if (!(eta->ref_list.append_str(thd->mem_root, (*key_ref)->name())))
            return 1;
          key_ref++;
        }
      }
    }
  }

  if (tab_type == JT_HASH_NEXT) /* full index scan + hash join */
  {
    eta->hash_next_key.set(thd->mem_root, 
                           & table->key_info[index], 
                           table->key_info[index].key_length);
    // psergey-todo: ^ is the above correct? are we necessarily joining on all
    // columns?
  }

  if (!key_info)
  {
    if (table_list && /* SJM bushes don't have table_list */
        table_list->schema_table &&
        table_list->schema_table->i_s_requested_object & OPTIMIZE_I_S_TABLE)
    {
      IS_table_read_plan *is_table_read_plan= table_list->is_table_read_plan;
      const char *tmp_buff;
      int f_idx;
      StringBuffer<64> key_name_buf;
      if (is_table_read_plan->trivial_show_command ||
          is_table_read_plan->has_db_lookup_value())
      {
        /* The "key" has the name of the column referring to the database */
        f_idx= table_list->schema_table->idx_field1;
        tmp_buff= table_list->schema_table->fields_info[f_idx].field_name;
        key_name_buf.append(tmp_buff, strlen(tmp_buff), cs);
      }          
      if (is_table_read_plan->trivial_show_command ||
          is_table_read_plan->has_table_lookup_value())
      {
        if (is_table_read_plan->trivial_show_command ||
            is_table_read_plan->has_db_lookup_value())
          key_name_buf.append(',');

        f_idx= table_list->schema_table->idx_field2;
        tmp_buff= table_list->schema_table->fields_info[f_idx].field_name;
        key_name_buf.append(tmp_buff, strlen(tmp_buff), cs);
      }

      if (key_name_buf.length())
        eta->key.set_pseudo_key(thd->mem_root, key_name_buf.c_ptr_safe());
    }
  }
  
  /* "rows" */
  if (table_list /* SJM bushes don't have table_list */ &&
      table_list->schema_table)
  {
    /* I_S tables have rows=extra=NULL */
    eta->rows_set= false;
    eta->filtered_set= false;
  }
  else
  {
    ha_rows examined_rows= get_examined_rows();

    eta->rows_set= true;
    eta->rows= examined_rows;

    /* "filtered"  */
    float f= 0.0; 
    if (examined_rows)
    {
      double pushdown_cond_selectivity= cond_selectivity;
      if (pushdown_cond_selectivity == 1.0)
        f= (float) (100.0 * records_read / examined_rows);
      else
        f= (float) (100.0 * pushdown_cond_selectivity);
    }
    set_if_smaller(f, 100.0);
    eta->filtered_set= true;
    eta->filtered= f;
  }

  /* Build "Extra" field and save it */
  key_read= table->file->keyread_enabled();
  if ((tab_type == JT_NEXT || tab_type == JT_CONST) &&
      table->covering_keys.is_set(index))
    key_read=1;
  if (quick_type == QUICK_SELECT_I::QS_TYPE_ROR_INTERSECT &&
      !((QUICK_ROR_INTERSECT_SELECT*)cur_quick)->need_to_fetch_row)
    key_read=1;
    
  if (info)
  {
    eta->push_extra(info);
  }
  else if (packed_info & TAB_INFO_HAVE_VALUE)
  {
    if (packed_info & TAB_INFO_USING_INDEX)
      eta->push_extra(ET_USING_INDEX);
    if (packed_info & TAB_INFO_USING_WHERE)
      eta->push_extra(ET_USING_WHERE);
    if (packed_info & TAB_INFO_FULL_SCAN_ON_NULL)
      eta->push_extra(ET_FULL_SCAN_ON_NULL_KEY);
  }
  else
  {
    uint keyno= MAX_KEY;
    if (ref.key_parts)
      keyno= ref.key;
    else if (tab_select && cur_quick)
      keyno = cur_quick->index;

    if (keyno != MAX_KEY && keyno == table->file->pushed_idx_cond_keyno &&
        table->file->pushed_idx_cond)
    {
      eta->push_extra(ET_USING_INDEX_CONDITION);
      eta->pushed_index_cond= table->file->pushed_idx_cond;
    }
    else if (cache_idx_cond)
    {
      eta->push_extra(ET_USING_INDEX_CONDITION_BKA);
      eta->pushed_index_cond= cache_idx_cond;
    }

    if (quick_type == QUICK_SELECT_I::QS_TYPE_ROR_UNION || 
        quick_type == QUICK_SELECT_I::QS_TYPE_ROR_INTERSECT ||
        quick_type == QUICK_SELECT_I::QS_TYPE_INDEX_INTERSECT ||
        quick_type == QUICK_SELECT_I::QS_TYPE_INDEX_MERGE)
    {
      eta->push_extra(ET_USING);
    }
    if (tab_select)
    {
      if (use_quick == 2)
      {
        eta->push_extra(ET_RANGE_CHECKED_FOR_EACH_RECORD);
        eta->range_checked_fer= new (thd->mem_root) Explain_range_checked_fer;
        if (eta->range_checked_fer)
          eta->range_checked_fer->
            append_possible_keys_stat(thd->mem_root, table, keys);
      }
      else if (tab_select->cond ||
               (cache_select && cache_select->cond))
      {
        const COND *pushed_cond= table->file->pushed_cond;

        if ((table->file->ha_table_flags() &
              HA_CAN_TABLE_CONDITION_PUSHDOWN) &&
            pushed_cond)
        {
          eta->push_extra(ET_USING_WHERE_WITH_PUSHED_CONDITION);
        }
        else
        {
          eta->where_cond= tab_select->cond;
          eta->cache_cond= cache_select? cache_select->cond : NULL;
          eta->push_extra(ET_USING_WHERE);
        }
      }
    }
    if (table_list /* SJM bushes don't have table_list */ &&
        table_list->schema_table &&
        table_list->schema_table->i_s_requested_object & OPTIMIZE_I_S_TABLE)
    {
      if (!table_list->table_open_method)
        eta->push_extra(ET_SKIP_OPEN_TABLE);
      else if (table_list->table_open_method == OPEN_FRM_ONLY)
        eta->push_extra(ET_OPEN_FRM_ONLY);
      else
        eta->push_extra(ET_OPEN_FULL_TABLE);
      /* psergey-note: the following has a bug.*/
      if (table_list->is_table_read_plan->trivial_show_command ||
          (table_list->is_table_read_plan->has_db_lookup_value() &&
           table_list->is_table_read_plan->has_table_lookup_value()))
        eta->push_extra(ET_SCANNED_0_DATABASES);
      else if (table_list->is_table_read_plan->has_db_lookup_value() ||
               table_list->is_table_read_plan->has_table_lookup_value())
        eta->push_extra(ET_SCANNED_1_DATABASE);
      else
        eta->push_extra(ET_SCANNED_ALL_DATABASES);
    }
    if (key_read)
    {
      if (quick_type == QUICK_SELECT_I::QS_TYPE_GROUP_MIN_MAX)
      {
        QUICK_GROUP_MIN_MAX_SELECT *qgs= 
          (QUICK_GROUP_MIN_MAX_SELECT *) tab_select->quick;
        eta->push_extra(ET_USING_INDEX_FOR_GROUP_BY);
        eta->loose_scan_is_scanning= qgs->loose_scan_is_scanning();
      }
      else
        eta->push_extra(ET_USING_INDEX);
    }
    if (table->reginfo.not_exists_optimize)
      eta->push_extra(ET_NOT_EXISTS);

    if (quick_type == QUICK_SELECT_I::QS_TYPE_RANGE)
    {
      explain_append_mrr_info((QUICK_RANGE_SELECT*)(tab_select->quick),
                              &eta->mrr_type);
      if (eta->mrr_type.length() > 0)
        eta->push_extra(ET_USING_MRR);
    }

    if (shortcut_for_distinct)
      eta->push_extra(ET_DISTINCT);

    if (loosescan_match_tab)
    {
      eta->push_extra(ET_LOOSESCAN);
    }

    if (first_weedout_table)
    {
      eta->start_dups_weedout= true;
      eta->push_extra(ET_START_TEMPORARY);
    }
    if (check_weed_out_table)
    {
      eta->push_extra(ET_END_TEMPORARY);
      eta->end_dups_weedout= true;
    }

    else if (do_firstmatch)
    {
      if (do_firstmatch == /*join->join_tab*/ first_top_tab - 1)
        eta->push_extra(ET_FIRST_MATCH);
      else
      {
        eta->push_extra(ET_FIRST_MATCH);
        TABLE *prev_table=do_firstmatch->table;
        if (prev_table->derived_select_number)
        {
          char namebuf[NAME_LEN];
          /* Derived table name generation */
          size_t len= my_snprintf(namebuf, sizeof(namebuf)-1,
                               "<derived%u>",
                               prev_table->derived_select_number);
          eta->firstmatch_table_name.append(namebuf, len);
        }
        else
          eta->firstmatch_table_name.append(&prev_table->pos_in_table_list->alias);
      }
    }

    for (uint part= 0; part < ref.key_parts; part++)
    {
      if (ref.cond_guards[part])
      {
        eta->push_extra(ET_FULL_SCAN_ON_NULL_KEY);
        eta->full_scan_on_null_key= true;
        break;
      }
    }

    if (cache)
    {
      eta->push_extra(ET_USING_JOIN_BUFFER);
      if (cache->save_explain_data(&eta->bka_type))
        return 1;
    }
  }

  /* 
    In case this is a derived table, here we remember the number of 
    subselect that used to produce it.
  */
  if (!(table_list && table_list->is_with_table_recursive_reference()))
    eta->derived_select_number= table->derived_select_number;

  /* The same for non-merged semi-joins */
  eta->non_merged_sjm_number = get_non_merged_semijoin_select();

  return 0;
}

Project: server

bool JOIN::change_result(select_result *new_result, select_result *old_result)
{
  DBUG_ENTER("JOIN::change_result");
  if (old_result == NULL || result == old_result)
  {
    result= new_result;
    if (result->prepare(fields_list, select_lex->master_unit()) ||
        result->prepare2(this))
      DBUG_RETURN(true); /* purecov: inspected */
    DBUG_RETURN(false);
  }
  DBUG_RETURN(result->change_result(new_result));
}

Project: server

void set_join_cache_denial(JOIN_TAB *join_tab)
{
  if (join_tab->cache)
  {
    /* 
      If there is a previous cache linked to this cache through the
      next_cache pointer: remove the link. 
    */
    if (join_tab->cache->prev_cache)
      join_tab->cache->prev_cache->next_cache= 0;
    /*
      Same for the next_cache
    */
    if (join_tab->cache->next_cache)
      join_tab->cache->next_cache->prev_cache= 0;

    join_tab->cache->free();
    join_tab->cache= 0;
  }
  if (join_tab->use_join_cache)
  {
    join_tab->use_join_cache= FALSE;
    join_tab->used_join_cache_level= 0;
    /*
      It could be only sub_select(). It could not be sub_seject_sjm because we
      don't do join buffering for the first table in sjm nest. 
    */
    join_tab[-1].next_select= sub_select;
    if (join_tab->type == JT_REF && join_tab->is_ref_for_hash_join())
    {
      join_tab->type= JT_ALL;
      join_tab->ref.key_parts= 0;
    }
    join_tab->join->return_tab= join_tab;
  }
}

Project: server

  static void operator delete(void *ptr __attribute__((unused)),
                              size_t size __attribute__((unused)))
  { TRASH_FREE(ptr, size); }

Project: server

static void choose_initial_table_order(JOIN *join)
{
  TABLE_LIST *emb_subq;
  JOIN_TAB **tab= join->best_ref + join->const_tables;
  JOIN_TAB **tabs_end= tab + join->table_count - join->const_tables;
  DBUG_ENTER("choose_initial_table_order");
  /* Find where the top-level JOIN_TABs end and subquery JOIN_TABs start */
  for (; tab != tabs_end; tab++)
  {
    if ((emb_subq= get_emb_subq(*tab)))
      break;
  }
  uint n_subquery_tabs= (uint)(tabs_end - tab);

  if (!n_subquery_tabs)
    DBUG_VOID_RETURN;

  /* Copy the subquery JOIN_TABs to a separate array */
  JOIN_TAB *subquery_tabs[MAX_TABLES];
  memcpy(subquery_tabs, tab, sizeof(JOIN_TAB*) * n_subquery_tabs);
  
  JOIN_TAB **last_top_level_tab= tab;
  JOIN_TAB **subq_tab= subquery_tabs;
  JOIN_TAB **subq_tabs_end= subquery_tabs + n_subquery_tabs;
  TABLE_LIST *cur_subq_nest= NULL;
  for (; subq_tab < subq_tabs_end; subq_tab++)
  {
    if (get_emb_subq(*subq_tab)!= cur_subq_nest)
    {
      /*
        Reached the part of subquery_tabs that covers tables in some subquery.
      */
      cur_subq_nest= get_emb_subq(*subq_tab);

      /* Determine how many tables the subquery has */
      JOIN_TAB **last_tab_for_subq;
      for (last_tab_for_subq= subq_tab;
           last_tab_for_subq < subq_tabs_end && 
           get_emb_subq(*last_tab_for_subq) == cur_subq_nest;
           last_tab_for_subq++) {}
      uint n_subquery_tables= (uint)(last_tab_for_subq - subq_tab);

      /* 
        Walk the original array and find where this subquery would have been
        attached to
      */
      table_map need_tables= cur_subq_nest->original_subq_pred_used_tables;
      need_tables &= ~(join->const_table_map | PSEUDO_TABLE_BITS);
      for (JOIN_TAB **top_level_tab= join->best_ref + join->const_tables;
           top_level_tab < last_top_level_tab;
           //top_level_tab < join->best_ref + join->table_count;
           top_level_tab++)
      {
        need_tables &= ~(*top_level_tab)->table->map;
        /* Check if this is the place where subquery should be attached */
        if (!need_tables)
        {
          /* Move away the top-level tables that are after top_level_tab */
          size_t top_tail_len= last_top_level_tab - top_level_tab - 1;
          memmove(top_level_tab + 1 + n_subquery_tables, top_level_tab + 1,
                  sizeof(JOIN_TAB*)*top_tail_len);
          last_top_level_tab += n_subquery_tables;
          memcpy(top_level_tab + 1, subq_tab, sizeof(JOIN_TAB*)*n_subquery_tables);
          break;
        }
      }
      DBUG_ASSERT(!need_tables);
      subq_tab += n_subquery_tables - 1;
    }
  }
  DBUG_VOID_RETURN;
}

Project: server

inline void add_cond_and_fix(THD *thd, Item **e1, Item *e2)
{
  if (*e1)
  {
    if (!e2)
      return;
    Item *res;
    if ((res= new (thd->mem_root) Item_cond_and(thd, *e1, e2)))
    {
      res->fix_fields(thd, 0);
      res->update_used_tables();
      *e1= res;
    }
  }
  else
    *e1= e2;
}

Project: server

uint get_index_for_order(ORDER *order, TABLE *table, SQL_SELECT *select,
                         ha_rows limit, ha_rows *scanned_limit,
                         bool *need_sort, bool *reverse)
{
  if (!order)
  {
    *need_sort= FALSE;
    if (select && select->quick)
      return select->quick->index; // index or MAX_KEY, use quick select as is
    else
      return table->file->key_used_on_scan; // MAX_KEY or index for some engines
  }

  if (!is_simple_order(order)) // just to cut further expensive checks
  {
    *need_sort= TRUE;
    return MAX_KEY;
  }

  if (select && select->quick)
  {
    if (select->quick->index == MAX_KEY)
    {
      *need_sort= TRUE;
      return MAX_KEY;
    }

    uint used_key_parts;
    switch (test_if_order_by_key(NULL, order, table, select->quick->index,
                                 &used_key_parts)) {
    case 1: // desired order
      *need_sort= FALSE; 
      *scanned_limit= MY_MIN(limit, select->quick->records);
      return select->quick->index;
    case 0: // unacceptable order
      *need_sort= TRUE;
      return MAX_KEY;
    case -1: // desired order, but opposite direction
      {
        QUICK_SELECT_I *reverse_quick;
        if ((reverse_quick=
               select->quick->make_reverse(used_key_parts)))
        {
          select->set_quick(reverse_quick);
          *need_sort= FALSE;
          *scanned_limit= MY_MIN(limit, select->quick->records);
          return select->quick->index;
        }
        else
        {
          *need_sort= TRUE;
          return MAX_KEY;
        }
      }
    }
    DBUG_ASSERT(0);
  }
  else if (limit != HA_POS_ERROR)
  { // check if some index scan & LIMIT is more efficient than filesort
    
    /*
      Update quick_condition_rows since single table UPDATE/DELETE procedures
      don't call make_join_statistics() and leave this variable uninitialized.
    */
    table->quick_condition_rows= table->stat_records();
    
    int key, direction;
    if (test_if_cheaper_ordering(NULL, order, table,
                                 table->keys_in_use_for_order_by, -1,
                                 limit,
                                 &key, &direction, &limit) &&
        !is_key_used(table, key, table->write_set))
    {
      *need_sort= FALSE;
      *scanned_limit= limit;
      *reverse= (direction < 0);
      return key;
    }
  }
  *need_sort= TRUE;
  return MAX_KEY;
}

Project: server

add_group_and_distinct_keys(JOIN *join, JOIN_TAB *join_tab)
{
  List<Item_field> indexed_fields;
  List_iterator<Item_field> indexed_fields_it(indexed_fields);
  ORDER      *cur_group;
  Item_field *cur_item;
  key_map possible_keys(0);

  if (join->group_list)
  { /* Collect all query fields referenced in the GROUP clause. */
    for (cur_group= join->group_list; cur_group; cur_group= cur_group->next)
      (*cur_group->item)->walk(&Item::collect_item_field_processor, 0,
                               &indexed_fields);
  }
  else if (join->select_distinct)
  { /* Collect all query fields referenced in the SELECT clause. */
    List<Item> &select_items= join->fields_list;
    List_iterator<Item> select_items_it(select_items);
    Item *item;
    while ((item= select_items_it++))
      item->walk(&Item::collect_item_field_processor, 0, &indexed_fields);
  }
  else if (join->tmp_table_param.sum_func_count &&
           is_indexed_agg_distinct(join, &indexed_fields))
  {
    join->sort_and_group= 1;
  }
  else
    return;

  if (indexed_fields.elements == 0)
    return;

  /* Intersect the keys of all group fields. */
  cur_item= indexed_fields_it++;
  possible_keys.merge(cur_item->field->part_of_key);
  while ((cur_item= indexed_fields_it++))
  {
    possible_keys.intersect(cur_item->field->part_of_key);
  }

  if (!possible_keys.is_clear_all())
    join_tab->const_keys.merge(possible_keys);
}

Project: server

void JOIN_TAB::calc_used_field_length(bool max_fl)
{
  uint null_fields,blobs,fields;
  ulong rec_length;
  Field **f_ptr,*field;
  uint uneven_bit_fields;
  MY_BITMAP *read_set= table->read_set;

  uneven_bit_fields= null_fields= blobs= fields= rec_length=0;
  for (f_ptr=table->field ; (field= *f_ptr) ; f_ptr++)
  {
    if (bitmap_is_set(read_set, field->field_index))
    {
      uint flags=field->flags;
      fields++;
      rec_length+=field->pack_length();
      if (flags & BLOB_FLAG)
	blobs++;
      if (!(flags & NOT_NULL_FLAG))
	null_fields++;
      if (field->type() == MYSQL_TYPE_BIT &&
          ((Field_bit*)field)->bit_len)
        uneven_bit_fields++;
    }
  }
  if (null_fields || uneven_bit_fields)
    rec_length+=(table->s->null_fields+7)/8;
  if (table->maybe_null)
    rec_length+=sizeof(my_bool);

  /* Take into account that DuplicateElimination may need to store rowid */
  uint rowid_add_size= 0;
  if (keep_current_rowid)
  {
    rowid_add_size= table->file->ref_length; 
    rec_length += rowid_add_size;
    fields++;
  }

  if (max_fl)
  {
    // TODO: to improve this estimate for max expected length 
    if (blobs)
    {
      ulong blob_length= table->file->stats.mean_rec_length;
      if (ULONG_MAX - rec_length > blob_length)
        rec_length+=  blob_length;
      else
        rec_length= ULONG_MAX;
    }
    max_used_fieldlength= rec_length;
  } 
  else if (table->file->stats.mean_rec_length)
    set_if_smaller(rec_length, table->file->stats.mean_rec_length + rowid_add_size);
      
  used_fields=fields;
  used_fieldlength=rec_length;
  used_blobs=blobs;
  used_null_fields= null_fields;
  used_uneven_bit_fields= uneven_bit_fields;
}

Project: server

setup_tmp_table_column_bitmaps(TABLE *table, uchar *bitmaps)
{
  setup_tmp_table_column_bitmaps(table, bitmaps, table->s->fields);
}

Project: server

sub_select_postjoin_aggr(JOIN *join, JOIN_TAB *join_tab, bool end_of_records)
{
  enum_nested_loop_state rc;
  AGGR_OP *aggr= join_tab->aggr;

  /* This function cannot be called if join_tab has no associated aggregation */
  DBUG_ASSERT(aggr != NULL);

  DBUG_ENTER("sub_select_aggr_tab");

  if (join->thd->killed)
  {
    /* The user has aborted the execution of the query */
    join->thd->send_kill_message();
    DBUG_RETURN(NESTED_LOOP_KILLED);
  }

  if (end_of_records)
  {
    rc= aggr->end_send();
    if (rc >= NESTED_LOOP_OK)
      rc= sub_select(join, join_tab, end_of_records);
    DBUG_RETURN(rc);
  }

  rc= aggr->put_record();

  DBUG_RETURN(rc);
}

Project: server

greedy_search(JOIN      *join,
              table_map remaining_tables,
              uint      search_depth,
              uint      prune_level,
              uint      use_cond_selectivity)
{
  double    record_count= 1.0;
  double    read_time=    0.0;
  uint      idx= join->const_tables; // index into 'join->best_ref'
  uint      best_idx;
  uint      size_remain;    // cardinality of remaining_tables
  POSITION  best_pos;
  JOIN_TAB  *best_table; // the next plan node to be added to the curr QEP
  // ==join->tables or # tables in the sj-mat nest we're optimizing
  uint      n_tables __attribute__((unused));
  DBUG_ENTER("greedy_search");

  /* number of tables that remain to be optimized */
  n_tables= size_remain= my_count_bits(remaining_tables &
                                       (join->emb_sjm_nest? 
                                         (join->emb_sjm_nest->sj_inner_tables &
                                          ~join->const_table_map)
                                         :
                                         ~(table_map)0));

  do {
    /* Find the extension of the current QEP with the lowest cost */
    join->best_read= DBL_MAX;
    if (best_extension_by_limited_search(join, remaining_tables, idx, record_count,
                                         read_time, search_depth, prune_level,
                                         use_cond_selectivity))
      DBUG_RETURN(TRUE);
    /*
      'best_read < DBL_MAX' means that optimizer managed to find
      some plan and updated 'best_positions' array accordingly.
    */
    DBUG_ASSERT(join->best_read < DBL_MAX);

    if (size_remain <= search_depth)
    {
      /*
        'join->best_positions' contains a complete optimal extension of the
        current partial QEP.
      */
      DBUG_EXECUTE("opt", print_plan(join, n_tables,
                                     record_count, read_time, read_time,
                                     "optimal"););
      DBUG_RETURN(FALSE);
    }

    /* select the first table in the optimal extension as most promising */
    best_pos= join->best_positions[idx];
    best_table= best_pos.table;
    /*
      Each subsequent loop of 'best_extension_by_limited_search' uses
      'join->positions' for cost estimates, therefore we have to update its
      value.
    */
    join->positions[idx]= best_pos;

    /*
      Update the interleaving state after extending the current partial plan
      with a new table.
      We are doing this here because best_extension_by_limited_search reverts
      the interleaving state to the one of the non-extended partial plan 
      on exit.
    */
    bool is_interleave_error __attribute__((unused))= 
      check_interleaving_with_nj (best_table);
    /* This has been already checked by best_extension_by_limited_search */
    DBUG_ASSERT(!is_interleave_error);


    /* find the position of 'best_table' in 'join->best_ref' */
    best_idx= idx;
    JOIN_TAB *pos= join->best_ref[best_idx];
    while (pos && best_table != pos)
      pos= join->best_ref[++best_idx];
    DBUG_ASSERT((pos != NULL)); // should always find 'best_table'
    /* move 'best_table' at the first free position in the array of joins */
    swap_variables(JOIN_TAB*, join->best_ref[idx], join->best_ref[best_idx]);

    /* compute the cost of the new plan extended with 'best_table' */
    record_count= COST_MULT(record_count, join->positions[idx].records_read);
    read_time= COST_ADD(read_time,
                         COST_ADD(join->positions[idx].read_time,
                                  record_count / (double) TIME_FOR_COMPARE));

    remaining_tables&= ~(best_table->table->map);
    --size_remain;
    ++idx;

    DBUG_EXECUTE("opt", print_plan(join, idx,
                                   record_count, read_time, read_time,
                                   "extended"););
  } while (TRUE);
}

Project: server

int report_error(TABLE *table, int error)
{
  if (error == HA_ERR_END_OF_FILE || error == HA_ERR_KEY_NOT_FOUND)
  {
    table->status= STATUS_GARBAGE;
    return -1;					// key not found; ok
  }
  /*
    Locking reads can legally return also these errors, do not
    print them to the .err log
  */
  if (error != HA_ERR_LOCK_DEADLOCK && error != HA_ERR_LOCK_WAIT_TIMEOUT
      && error != HA_ERR_TABLE_DEF_CHANGED && !table->in_use->killed)
    sql_print_error("Got error %d when reading table '%s'",
		    error, table->s->path.str);
  table->file->print_error(error,MYF(0));
  return 1;
}

Project: server

sub_select(JOIN *join,JOIN_TAB *join_tab,bool end_of_records)
{
  DBUG_ENTER("sub_select");

  if (join_tab->last_inner)
  {
    JOIN_TAB *last_inner_tab= join_tab->last_inner;
    for (JOIN_TAB  *jt= join_tab; jt <= last_inner_tab; jt++)
      jt->table->null_row= 0;
  }
  else
    join_tab->table->null_row=0;

  if (end_of_records)
  {
    enum_nested_loop_state nls=
      (*join_tab->next_select)(join,join_tab+1,end_of_records);
    DBUG_RETURN(nls);
  }
  join_tab->tracker->r_scans++;

  int error;
  enum_nested_loop_state rc= NESTED_LOOP_OK;
  READ_RECORD *info= &join_tab->read_record;


  for (SJ_TMP_TABLE *flush_dups_table= join_tab->flush_weedout_table;
       flush_dups_table;
       flush_dups_table= flush_dups_table->next_flush_table)
  {
    flush_dups_table->sj_weedout_delete_rows();
  }

  if (!join_tab->preread_init_done && join_tab->preread_init())
    DBUG_RETURN(NESTED_LOOP_ERROR);

  join->return_tab= join_tab;

  if (join_tab->last_inner)
  {
    /* join_tab is the first inner table for an outer join operation. */

    /* Set initial state of guard variables for this table.*/
    join_tab->found=0;
    join_tab->not_null_compl= 1;

    /* Set first_unmatched for the last inner table of this group */
    join_tab->last_inner->first_unmatched= join_tab;
    if (join_tab->on_precond && !join_tab->on_precond->val_int())
      rc= NESTED_LOOP_NO_MORE_ROWS;
  }
  join->thd->get_stmt_da()->reset_current_row_for_warning();

  if (rc != NESTED_LOOP_NO_MORE_ROWS && 
      (rc= join_tab_execution_startup(join_tab)) < 0)
    DBUG_RETURN(rc);
  
  if (join_tab->loosescan_match_tab)
    join_tab->loosescan_match_tab->found_match= FALSE;

  if (rc != NESTED_LOOP_NO_MORE_ROWS)
  {
    error= (*join_tab->read_first_record)(join_tab);
    if (!error && join_tab->keep_current_rowid)
      join_tab->table->file->position(join_tab->table->record[0]);    
    rc= evaluate_join_record(join, join_tab, error);
  }

  /* 
    Note: psergey has added the 2nd part of the following condition; the 
    change should probably be made in 5.1, too.
  */
  bool skip_over= FALSE;
  while (rc == NESTED_LOOP_OK && join->return_tab >= join_tab)
  {
    if (join_tab->loosescan_match_tab && 
        join_tab->loosescan_match_tab->found_match)
    {
      KEY *key= join_tab->table->key_info + join_tab->loosescan_key;
      key_copy(join_tab->loosescan_buf, join_tab->table->record[0], key, 
               join_tab->loosescan_key_len);
      skip_over= TRUE;
    }

    error= info->read_record();

    if (skip_over && likely(!error))
    {
      if (!key_cmp(join_tab->table->key_info[join_tab->loosescan_key].key_part,
                   join_tab->loosescan_buf, join_tab->loosescan_key_len))
      {
        /* 
          This is the LooseScan action: skip over records with the same key
          value if we already had a match for them.
        */
        continue;
      }
      join_tab->loosescan_match_tab->found_match= FALSE;
      skip_over= FALSE;
    }

    if (join_tab->keep_current_rowid && likely(!error))
      join_tab->table->file->position(join_tab->table->record[0]);
    
    rc= evaluate_join_record(join, join_tab, error);
  }

  if (rc == NESTED_LOOP_NO_MORE_ROWS &&
      join_tab->last_inner && !join_tab->found)
    rc= evaluate_null_complemented_join_record(join, join_tab);

  if (rc == NESTED_LOOP_NO_MORE_ROWS)
    rc= NESTED_LOOP_OK;
  DBUG_RETURN(rc);
}

Project: server

JOIN_TAB::remove_duplicates()

{
  bool error;
  ulong keylength= 0;
  uint field_count;
  List<Item> *fields= (this-1)->fields;
  THD *thd= join->thd;

  DBUG_ENTER("remove_duplicates");

  DBUG_ASSERT(join->aggr_tables > 0 && table->s->tmp_table != NO_TMP_TABLE);
  THD_STAGE_INFO(join->thd, stage_removing_duplicates);

  //join->explain->ops_tracker.report_duplicate_removal();

  table->reginfo.lock_type=TL_WRITE;

  /* Calculate how many saved fields there is in list */
  field_count=0;
  List_iterator<Item> it(*fields);
  Item *item;
  while ((item=it++))
  {
    if (item->get_tmp_table_field() && ! item->const_item())
      field_count++;
  }

  if (!field_count && !(join->select_options & OPTION_FOUND_ROWS) && !having) 
  {                    // only const items with no OPTION_FOUND_ROWS
    join->unit->select_limit_cnt= 1;		// Only send first row
    DBUG_RETURN(false);
  }

  Field **first_field=table->field+table->s->fields - field_count;
  for (Field **ptr=first_field; *ptr; ptr++)
    keylength+= (*ptr)->sort_length() + (*ptr)->maybe_null();

  /*
    Disable LIMIT ROWS EXAMINED in order to avoid interrupting prematurely
    duplicate removal, and produce a possibly incomplete query result.
  */
  thd->lex->limit_rows_examined_cnt= ULONGLONG_MAX;
  if (thd->killed == ABORT_QUERY)
    thd->reset_killed();

  table->file->info(HA_STATUS_VARIABLE);
  if (table->s->db_type() == heap_hton ||
      (!table->s->blob_fields &&
       ((ALIGN_SIZE(keylength) + HASH_OVERHEAD) * table->file->stats.records <
	thd->variables.sortbuff_size)))
    error=remove_dup_with_hash_index(join->thd, table, field_count, first_field,
				     keylength, having);
  else
    error=remove_dup_with_compare(join->thd, table, first_field, having);

  if (join->select_lex != join->select_lex->master_unit()->fake_select_lex)
    thd->lex->set_limit_rows_examined();
  free_blobs(first_field);
  DBUG_RETURN(error);
}

Project: server

add_key_part(DYNAMIC_ARRAY *keyuse_array, KEY_FIELD *key_field)
{
  Field *field=key_field->field;
  TABLE *form= field->table;

  if (key_field->eq_func && !(key_field->optimize & KEY_OPTIMIZE_EXISTS))
  {
    for (uint key=0 ; key < form->s->keys ; key++)
    {
      if (!(form->keys_in_use_for_query.is_set(key)))
	continue;
      if (form->key_info[key].flags & (HA_FULLTEXT | HA_SPATIAL))
	continue;    // ToDo: ft-keys in non-ft queries.   SerG

      KEY *keyinfo= form->key_info+key;
      uint key_parts= form->actual_n_key_parts(keyinfo);
      for (uint part=0 ; part <  key_parts ; part++)
      {
        if (field->eq(form->key_info[key].key_part[part].field) &&
            field->can_optimize_keypart_ref(key_field->cond, key_field->val))
	{
          if (add_keyuse(keyuse_array, key_field, key, part))
            return TRUE;
	}
      }
    }
    if (field->hash_join_is_possible() &&
        (key_field->optimize & KEY_OPTIMIZE_EQ) &&
        key_field->val->used_tables())
    {
      if (!field->can_optimize_hash_join(key_field->cond, key_field->val))
        return false;
      if (form->is_splittable())
        form->add_splitting_info_for_key_field(key_field);
      /* 
        If a key use is extracted from an equi-join predicate then it is
        added not only as a key use for every index whose component can
        be evalusted utilizing this key use, but also as a key use for
        hash join. Such key uses are marked with a special key number. 
      */    
      if (add_keyuse(keyuse_array, key_field, get_hash_join_key_no(), 0))
        return TRUE;
    }
  }
  return FALSE;
}

Project: server

join_read_first(JOIN_TAB *tab)
{
  int error= 0;
  TABLE *table=tab->table;
  DBUG_ENTER("join_read_first");

  DBUG_ASSERT(table->no_keyread ||
              !table->covering_keys.is_set(tab->index) ||
              table->file->keyread == tab->index);
  tab->table->status=0;
  tab->read_record.read_record_func= join_read_next;
  tab->read_record.table=table;
  if (!table->file->inited)
    error= table->file->ha_index_init(tab->index, tab->sorted);
  if (likely(!error))
    error= table->file->prepare_index_scan();
  if (unlikely(error) ||
      unlikely(error= tab->table->file->ha_index_first(tab->table->record[0])))
  {
    if (error != HA_ERR_KEY_NOT_FOUND && error != HA_ERR_END_OF_FILE)
      report_error(table, error);
    DBUG_RETURN(-1);
  }
  DBUG_RETURN(0);
}

Project: server

ulong check_selectivity(THD *thd,
                        ulong rows_to_read,
                        TABLE *table,
                        List<COND_STATISTIC> *conds)
{
  ulong count= 0;
  COND_STATISTIC *cond;
  List_iterator_fast<COND_STATISTIC> it(*conds);
  handler *file= table->file;
  uchar *record= table->record[0];
  int error= 0;
  DBUG_ENTER("check_selectivity");

  DBUG_ASSERT(rows_to_read > 0);
  while ((cond= it++))
  {
    DBUG_ASSERT(cond->cond);
    DBUG_ASSERT(cond->cond->used_tables() == table->map);
    cond->positive= 0;
  }
  it.rewind();

  if (unlikely(file->ha_rnd_init_with_error(1)))
    DBUG_RETURN(0);
  do
  {
    error= file->ha_rnd_next(record);

    if (unlikely(thd->killed))
    {
      thd->send_kill_message();
      count= 0;
      goto err;
    }
    if (unlikely(error))
    {
      if (error == HA_ERR_END_OF_FILE)
	break;
      goto err;
    }

    count++;
    while ((cond= it++))
    {
      if (cond->cond->val_bool())
        cond->positive++;
    }
    it.rewind();

  } while (count < rows_to_read);

  file->ha_rnd_end();
  DBUG_RETURN(count);

err:
  DBUG_PRINT("error", ("error %d", error));
  file->ha_rnd_end();
  DBUG_RETURN(0);
}

Project: server

best_extension_by_limited_search(JOIN      *join,
                                 table_map remaining_tables,
                                 uint      idx,
                                 double    record_count,
                                 double    read_time,
                                 uint      search_depth,
                                 uint      prune_level,
                                 uint      use_cond_selectivity)
{
  DBUG_ENTER("best_extension_by_limited_search");

  THD *thd= join->thd;

  DBUG_EXECUTE_IF("show_explain_probe_best_ext_lim_search", 
                  if (dbug_user_var_equals_int(thd, 
                                               "show_explain_probe_select_id", 
                                               join->select_lex->select_number))
                        dbug_serve_apcs(thd, 1);
                 );

  if (unlikely(thd->check_killed()))  // Abort
    DBUG_RETURN(TRUE);

  DBUG_EXECUTE("opt", print_plan(join, idx, read_time, record_count, idx,
                                 "SOFAR:"););

  /* 
     'join' is a partial plan with lower cost than the best plan so far,
     so continue expanding it further with the tables in 'remaining_tables'.
  */
  JOIN_TAB *s;
  double best_record_count= DBL_MAX;
  double best_read_time=    DBL_MAX;
  bool disable_jbuf= join->thd->variables.join_cache_level == 0;

  DBUG_EXECUTE("opt", print_plan(join, idx, record_count, read_time, read_time,
                                "part_plan"););

  /* 
    If we are searching for the execution plan of a materialized semi-join nest
    then allowed_tables contains bits only for the tables from this nest.
  */
  table_map allowed_tables= ~(table_map)0;
  if (join->emb_sjm_nest)
    allowed_tables= join->emb_sjm_nest->sj_inner_tables & ~join->const_table_map;

  for (JOIN_TAB **pos= join->best_ref + idx ; (s= *pos) ; pos++)
  {
    table_map real_table_bit= s->table->map;
    if ((remaining_tables & real_table_bit) && 
        (allowed_tables & real_table_bit) &&
        !(remaining_tables & s->dependent) && 
        (!idx || !check_interleaving_with_nj(s)))
    {
      double current_record_count, current_read_time;
      POSITION *position= join->positions + idx;

      /* Find the best access method from 's' to the current partial plan */
      POSITION loose_scan_pos;
      best_access_path(join, s, remaining_tables, join->positions, idx,
                       disable_jbuf, record_count, position, &loose_scan_pos);

      /* Compute the cost of extending the plan with 's' */
      current_record_count= COST_MULT(record_count, position->records_read);
      current_read_time=COST_ADD(read_time,
                                 COST_ADD(position->read_time,
                                          current_record_count /
                                          (double) TIME_FOR_COMPARE));

      advance_sj_state(join, remaining_tables, idx, &current_record_count,
                       &current_read_time, &loose_scan_pos);

      /* Expand only partial plans with lower cost than the best QEP so far */
      if (current_read_time >= join->best_read)
      {
        DBUG_EXECUTE("opt", print_plan(join, idx+1,
                                       current_record_count,
                                       read_time,
                                       current_read_time,
                                       "prune_by_cost"););
        restore_prev_nj_state(s);
        restore_prev_sj_state(remaining_tables, s, idx);
        continue;
      }

      /*
        Prune some less promising partial plans. This heuristic may miss
        the optimal QEPs, thus it results in a non-exhaustive search.
      */
      if (prune_level == 1)
      {
        if (best_record_count > current_record_count ||
            best_read_time > current_read_time ||
            (idx == join->const_tables &&  // 's' is the first table in the QEP
            s->table == join->sort_by_table))
        {
          if (best_record_count >= current_record_count &&
              best_read_time >= current_read_time &&
              /* TODO: What is the reasoning behind this condition? */
              (!(s->key_dependent & allowed_tables & remaining_tables) ||
               join->positions[idx].records_read < 2.0))
          {
            best_record_count= current_record_count;
            best_read_time=    current_read_time;
          }
        }
        else
        {
          DBUG_EXECUTE("opt", print_plan(join, idx+1,
                                         current_record_count,
                                         read_time,
                                         current_read_time,
                                         "pruned_by_heuristic"););
          restore_prev_nj_state(s);
          restore_prev_sj_state(remaining_tables, s, idx);
          continue;
        }
      }

      double pushdown_cond_selectivity= 1.0;
      if (use_cond_selectivity > 1)
        pushdown_cond_selectivity= table_cond_selectivity(join, idx, s,
				                          remaining_tables &
                                                          ~real_table_bit);
      join->positions[idx].cond_selectivity= pushdown_cond_selectivity;
      double partial_join_cardinality= current_record_count *
                                        pushdown_cond_selectivity;
      if ( (search_depth > 1) && (remaining_tables & ~real_table_bit) & allowed_tables )
      { /* Recursively expand the current partial plan */
        swap_variables(JOIN_TAB*, join->best_ref[idx], *pos);
        if (best_extension_by_limited_search(join,
                                             remaining_tables & ~real_table_bit,
                                             idx + 1,
                                             partial_join_cardinality,
                                             current_read_time,
                                             search_depth - 1,
                                             prune_level,
                                             use_cond_selectivity))
          DBUG_RETURN(TRUE);
        swap_variables(JOIN_TAB*, join->best_ref[idx], *pos);
      }
      else
      { /*
          'join' is either the best partial QEP with 'search_depth' relations,
          or the best complete QEP so far, whichever is smaller.
        */
        if (join->sort_by_table &&
            join->sort_by_table !=
            join->positions[join->const_tables].table->table)
          /*
             We may have to make a temp table, note that this is only a
             heuristic since we cannot know for sure at this point.
             Hence it may be wrong.
          */
          current_read_time= COST_ADD(current_read_time, current_record_count);
        if (current_read_time < join->best_read)
        {
          memcpy((uchar*) join->best_positions, (uchar*) join->positions,
                 sizeof(POSITION) * (idx + 1));
          join->join_record_count= partial_join_cardinality;
          join->best_read= current_read_time - 0.001;
        }
        DBUG_EXECUTE("opt", print_plan(join, idx+1,
                                       current_record_count,
                                       read_time,
                                       current_read_time,
                                       "full_plan"););
      }
      restore_prev_nj_state(s);
      restore_prev_sj_state(remaining_tables, s, idx);
    }
  }
  DBUG_RETURN(FALSE);
}

Project: server

static void calc_group_buffer(JOIN *join, ORDER *group)
{
  if (group)
    join->group= 1;
  calc_group_buffer(&join->tmp_table_param, group);
}

Project: server

static bool create_ref_for_key(JOIN *join, JOIN_TAB *j,
                               KEYUSE *org_keyuse, bool allow_full_scan, 
                               table_map used_tables)
{
  uint keyparts, length, key;
  TABLE *table;
  KEY *keyinfo;
  KEYUSE *keyuse= org_keyuse;
  bool ftkey= (keyuse->keypart == FT_KEYPART);
  THD *thd= join->thd;
  DBUG_ENTER("create_ref_for_key");

  /*  Use best key from find_best */
  table= j->table;
  key= keyuse->key;
  if (!is_hash_join_key_no(key))
    keyinfo= table->key_info+key;
  else
  {
    if (create_hj_key_for_table(join, j, org_keyuse, used_tables))
      DBUG_RETURN(TRUE);
    keyinfo= j->hj_key;
  }

  if (ftkey)
  {
    Item_func_match *ifm=(Item_func_match *)keyuse->val;

    length=0;
    keyparts=1;
    ifm->join_key=1;
  }
  else
  {
    keyparts=length=0;
    uint found_part_ref_or_null= 0;
    /*
      Calculate length for the used key
      Stop if there is a missing key part or when we find second key_part
      with KEY_OPTIMIZE_REF_OR_NULL
    */
    do
    {
      if (!(~used_tables & keyuse->used_tables) &&
          (!keyuse->validity_ref || *keyuse->validity_ref) &&
	  j->keyuse_is_valid_for_access_in_chosen_plan(join, keyuse))
      {
        if  (are_tables_local(j, keyuse->val->used_tables()))
        {
          if ((is_hash_join_key_no(key) && keyuse->keypart != NO_KEYPART) ||
              (!is_hash_join_key_no(key) && keyparts == keyuse->keypart &&
               !(found_part_ref_or_null & keyuse->optimize)))
          {
             length+= keyinfo->key_part[keyparts].store_length;
             keyparts++;
             found_part_ref_or_null|= keyuse->optimize & ~KEY_OPTIMIZE_EQ;
          }
        }
      }
      keyuse++;
    } while (keyuse->table == table && keyuse->key == key);

    if (!keyparts && allow_full_scan)
    {
      /* It's a LooseIndexScan strategy scanning whole index */
      j->type= JT_ALL;
      j->index= key;
      DBUG_RETURN(FALSE);
    }

    DBUG_ASSERT(length > 0);
    DBUG_ASSERT(keyparts != 0);
  } /* not ftkey */
  
  /* set up fieldref */
  j->ref.key_parts= keyparts;
  j->ref.key_length= length;
  j->ref.key= (int) key;
  if (!(j->ref.key_buff= (uchar*) thd->calloc(ALIGN_SIZE(length)*2)) ||
      !(j->ref.key_copy= (store_key**) thd->alloc((sizeof(store_key*) *
						          (keyparts+1)))) ||
      !(j->ref.items=(Item**) thd->alloc(sizeof(Item*)*keyparts)) ||
      !(j->ref.cond_guards= (bool**) thd->alloc(sizeof(uint*)*keyparts)))
  {
    DBUG_RETURN(TRUE);
  }
  j->ref.key_buff2=j->ref.key_buff+ALIGN_SIZE(length);
  j->ref.key_err=1;
  j->ref.has_record= FALSE;
  j->ref.null_rejecting= 0;
  j->ref.disable_cache= FALSE;
  j->ref.null_ref_part= NO_REF_PART;
  j->ref.const_ref_part_map= 0;
  j->ref.uses_splitting= FALSE;
  keyuse=org_keyuse;

  store_key **ref_key= j->ref.key_copy;
  uchar *key_buff=j->ref.key_buff, *null_ref_key= 0;
  uint null_ref_part= NO_REF_PART;
  bool keyuse_uses_no_tables= TRUE;
  uint not_null_keyparts= 0;
  if (ftkey)
  {
    j->ref.items[0]=((Item_func*)(keyuse->val))->key_item();
    /* Predicates pushed down into subquery can't be used FT access */
    j->ref.cond_guards[0]= NULL;
    if (keyuse->used_tables)
      DBUG_RETURN(TRUE);                        // not supported yet. SerG

    j->type=JT_FT;
  }
  else
  {
    uint i;
    for (i=0 ; i < keyparts ; keyuse++,i++)
    {
      while (((~used_tables) & keyuse->used_tables) ||
             (keyuse->validity_ref && !(*keyuse->validity_ref)) ||
	     !j->keyuse_is_valid_for_access_in_chosen_plan(join, keyuse) ||
             keyuse->keypart == NO_KEYPART ||
	     (keyuse->keypart != 
              (is_hash_join_key_no(key) ?
                 keyinfo->key_part[i].field->field_index : i)) || 
             !are_tables_local(j, keyuse->val->used_tables())) 
	 keyuse++;                              	/* Skip other parts */ 

      uint maybe_null= MY_TEST(keyinfo->key_part[i].null_bit);
      j->ref.items[i]=keyuse->val;		// Save for cond removal
      j->ref.cond_guards[i]= keyuse->cond_guard;

      if (!keyuse->val->maybe_null || keyuse->null_rejecting)
        not_null_keyparts++;
      /*
        Set ref.null_rejecting to true only if we are going to inject a
        "keyuse->val IS NOT NULL" predicate.
      */
      Item *real= (keyuse->val)->real_item();
      if (keyuse->null_rejecting && (real->type() == Item::FIELD_ITEM) &&
          ((Item_field*)real)->field->maybe_null())
        j->ref.null_rejecting|= (key_part_map)1 << i;

      keyuse_uses_no_tables= keyuse_uses_no_tables && !keyuse->used_tables;
      j->ref.uses_splitting |= (keyuse->validity_ref != NULL);
      /*
        We don't want to compute heavy expressions in EXPLAIN, an example would
        select * from t1 where t1.key=(select thats very heavy);

        (select thats very heavy) => is a constant here
        eg: (select avg(order_cost) from orders) => constant but expensive
      */
      if (!keyuse->val->used_tables() && !thd->lex->describe)
      {					// Compare against constant
        store_key_item tmp(thd,
                           keyinfo->key_part[i].field,
                           key_buff + maybe_null,
                           maybe_null ?  key_buff : 0,
                           keyinfo->key_part[i].length,
                           keyuse->val,
                           FALSE);
        if (unlikely(thd->is_fatal_error))
          DBUG_RETURN(TRUE);
        tmp.copy();
        j->ref.const_ref_part_map |= key_part_map(1) << i ;
      }
      else
      {
        *ref_key++= get_store_key(thd,
                                  keyuse,join->const_table_map,
                                  &keyinfo->key_part[i],
                                  key_buff, maybe_null);
        if (!keyuse->val->used_tables())
          j->ref.const_ref_part_map |= key_part_map(1) << i ;
      }
      /*
	Remember if we are going to use REF_OR_NULL
	But only if field _really_ can be null i.e. we force JT_REF
	instead of JT_REF_OR_NULL in case if field can't be null
      */
      if ((keyuse->optimize & KEY_OPTIMIZE_REF_OR_NULL) && maybe_null)
      {
	null_ref_key= key_buff;
        null_ref_part= i;
      }
      key_buff+= keyinfo->key_part[i].store_length;
    }
  } /* not ftkey */
  *ref_key=0;				// end_marker
  if (j->type == JT_FT)
    DBUG_RETURN(0);
  ulong key_flags= j->table->actual_key_flags(keyinfo);
  if (j->type == JT_CONST)
    j->table->const_table= 1;
  else if (!((keyparts == keyinfo->user_defined_key_parts &&
              (
                (key_flags & (HA_NOSAME | HA_NULL_PART_KEY)) == HA_NOSAME ||
                /* Unique key and all keyparts are NULL rejecting */
                ((key_flags & HA_NOSAME) && keyparts == not_null_keyparts)
              )) ||
              /* true only for extended keys */
              (keyparts > keyinfo->user_defined_key_parts &&
               MY_TEST(key_flags & HA_EXT_NOSAME) &&
               keyparts == keyinfo->ext_key_parts)
            ) ||
            null_ref_key)
  {
    /* Must read with repeat */
    j->type= null_ref_key ? JT_REF_OR_NULL : JT_REF;
    j->ref.null_ref_key= null_ref_key;
    j->ref.null_ref_part= null_ref_part;
  }
  else if (keyuse_uses_no_tables)
  {
    /*
      This happen if we are using a constant expression in the ON part
      of an LEFT JOIN.
      SELECT * FROM a LEFT JOIN b ON b.key=30
      Here we should not mark the table as a 'const' as a field may
      have a 'normal' value or a NULL value.
    */
    j->type=JT_CONST;
  }
  else
    j->type=JT_EQ_REF;

  j->read_record.unlock_row= (j->type == JT_EQ_REF)? 
                             join_read_key_unlock_row : rr_unlock_row; 
  DBUG_RETURN(0);
}

Project: server

Item_bool_func2::remove_eq_conds(THD *thd, Item::cond_result *cond_value,
                                 bool top_level_arg)
{
  if (const_item() && !is_expensive())
  {
    *cond_value= eval_const_cond() ? Item::COND_TRUE : Item::COND_FALSE;
    return (COND*) 0;
  }
  if ((*cond_value= eq_cmp_result()) != Item::COND_OK)
  {
    if (args[0]->eq(args[1], true))
    {
      if (!args[0]->maybe_null || functype() == Item_func::EQUAL_FUNC)
        return (COND*) 0;                       // Compare of identical items
    }
  }
  *cond_value= Item::COND_OK;
  return this;                                  // Point at next and level
}

Project: server

bool JOIN::add_having_as_table_cond(JOIN_TAB *tab)
{
  tmp_having->update_used_tables();
  table_map used_tables= tab->table->map | OUTER_REF_TABLE_BIT;

  /* If tmp table is not used then consider conditions of const table also */
  if (!need_tmp)
    used_tables|= const_table_map;

  DBUG_ENTER("JOIN::add_having_as_table_cond");

  Item* sort_table_cond= make_cond_for_table(thd, tmp_having, used_tables,
                                             (table_map) 0, false,
                                             false, false);
  if (sort_table_cond)
  {
    if (!tab->select)
    {
      if (!(tab->select= new SQL_SELECT))
        DBUG_RETURN(true);
      tab->select->head= tab->table;
    }
    if (!tab->select->cond)
      tab->select->cond= sort_table_cond;
    else
    {
      if (!(tab->select->cond=
	      new (thd->mem_root) Item_cond_and(thd,
                                                tab->select->cond,
                                                sort_table_cond)))
        DBUG_RETURN(true);
    }
    if (tab->pre_idx_push_select_cond)
    {
      if (sort_table_cond->type() == Item::COND_ITEM)
        sort_table_cond= sort_table_cond->copy_andor_structure(thd);
      if (!(tab->pre_idx_push_select_cond=
              new (thd->mem_root) Item_cond_and(thd,
                                                tab->pre_idx_push_select_cond,
                                                sort_table_cond)))
        DBUG_RETURN(true);
    }
    if (tab->select->cond)
      tab->select->cond->fix_fields_if_needed(thd, 0);
    if (tab->pre_idx_push_select_cond)
      tab->pre_idx_push_select_cond->fix_fields_if_needed(thd, 0);
    tab->select->pre_idx_push_select_cond= tab->pre_idx_push_select_cond;
    tab->set_select_cond(tab->select->cond, __LINE__);
    tab->select_cond->top_level_item();
    DBUG_EXECUTE("where",print_where(tab->select->cond,
				     "select and having",
                                     QT_ORDINARY););

    having= make_cond_for_table(thd, tmp_having, ~ (table_map) 0,
                                ~used_tables, false, false, false);
    DBUG_EXECUTE("where",
                 print_where(having, "having after sort", QT_ORDINARY););
  }

  DBUG_RETURN(false);
}

Project: server

cmp_buffer_with_ref(THD *thd, TABLE *table, TABLE_REF *tab_ref)
{
  bool no_prev_key;
  if (!tab_ref->disable_cache)
  {
    if (!(no_prev_key= tab_ref->key_err))
    {
      /* Previous access found a row. Copy its key */
      memcpy(tab_ref->key_buff2, tab_ref->key_buff, tab_ref->key_length);
    }
  }
  else 
    no_prev_key= TRUE;
  if ((tab_ref->key_err= cp_buffer_from_ref(thd, table, tab_ref)) ||
      no_prev_key)
    return 1;
  return memcmp(tab_ref->key_buff2, tab_ref->key_buff, tab_ref->key_length)
    != 0;
}

Project: server

Item_func_like::add_key_fields(JOIN *join, KEY_FIELD **key_fields,
                               uint *and_level, table_map usable_tables,
                               SARGABLE_PARAM **sargables)
{
  if (is_local_field(args[0]) && with_sargable_pattern())
  {
    /*
      SELECT * FROM t1 WHERE field LIKE const_pattern
      const_pattern starts with a non-wildcard character
    */
    add_key_equal_fields(join, key_fields, *and_level, this,
                         (Item_field*) args[0]->real_item(), false,
                         args + 1, 1, usable_tables, sargables);
  }
}

Project: server

void JOIN::reset_query_plan()
{
  for (uint i= 0; i < table_count; i++)
  {
    join_tab[i].keyuse= NULL;
    join_tab[i].checked_keys.clear_all();
  }
}

Project: server

int join_init_read_record(JOIN_TAB *tab)
{
  /* 
    Note: the query plan tree for the below operations is constructed in
    save_agg_explain_data.
  */
  if (tab->distinct && tab->remove_duplicates())  // Remove duplicates.
    return 1;
  if (tab->filesort && tab->sort_table())     // Sort table.
    return 1;

  DBUG_EXECUTE_IF("kill_join_init_read_record",
                  tab->join->thd->set_killed(KILL_QUERY););
  if (tab->select && tab->select->quick && tab->select->quick->reset())
  {
    /* Ensures error status is propagated back to client */
    report_error(tab->table,
                 tab->join->thd->killed ? HA_ERR_QUERY_INTERRUPTED : HA_ERR_OUT_OF_MEM);
    return 1;
  }
  /* make sure we won't get ER_QUERY_INTERRUPTED from any code below */
  DBUG_EXECUTE_IF("kill_join_init_read_record",
                  tab->join->thd->reset_killed(););
  if (!tab->preread_init_done  && tab->preread_init())
    return 1;
  if (init_read_record(&tab->read_record, tab->join->thd, tab->table,
                       tab->select, tab->filesort_result, 1,1, FALSE))
    return 1;
  return tab->read_record.read_record();
}

Project: server

test_if_quick_select(JOIN_TAB *tab)
{
  DBUG_EXECUTE_IF("show_explain_probe_test_if_quick_select", 
                  if (dbug_user_var_equals_int(tab->join->thd, 
                                               "show_explain_probe_select_id", 
                                               tab->join->select_lex->select_number))
                        dbug_serve_apcs(tab->join->thd, 1);
                 );


  delete tab->select->quick;
  tab->select->quick=0;

  if (tab->table->file->inited != handler::NONE)
    tab->table->file->ha_index_or_rnd_end();

  int res= tab->select->test_quick_select(tab->join->thd, tab->keys,
                                          (table_map) 0, HA_POS_ERROR, 0,
                                          FALSE, /*remove where parts*/FALSE);
  if (tab->explain_plan && tab->explain_plan->range_checked_fer)
    tab->explain_plan->range_checked_fer->collect_data(tab->select->quick);

  return res;
}

Project: server

bool build_tmp_join_prefix_cond(JOIN *join, JOIN_TAB *last_tab, Item **ret)
{
  THD *const thd= join->thd;
  Item_cond_and *all_conds= NULL;

  Item *res= NULL;

  // Pick the ON-expression. Use the same logic as in get_sargable_cond():
  if (last_tab->on_expr_ref)
    res= *last_tab->on_expr_ref;
  else if (last_tab->table->pos_in_table_list &&
           last_tab->table->pos_in_table_list->embedding &&
           !last_tab->table->pos_in_table_list->embedding->sj_on_expr)
  {
    res= last_tab->table->pos_in_table_list->embedding->on_expr;
  }

  for (JOIN_TAB *tab= first_depth_first_tab(join);
       tab;
       tab= next_depth_first_tab(join, tab))
  {
    if (tab->select_cond)
    {
      if (!res)
        res= tab->select_cond;
      else
      {
        if (!all_conds)
        {
          if (!(all_conds= new (thd->mem_root)Item_cond_and(thd, res,
                                                            tab->select_cond)))
            return true;
          res= all_conds;
        }
        else
          all_conds->add(tab->select_cond, thd->mem_root);
      }
    }
    if (tab == last_tab)
      break;
  }
  *ret= all_conds? all_conds: res;
  return false;
}

Project: server

cache_record_length(JOIN *join,uint idx)
{
  uint length=0;
  JOIN_TAB **pos,**end;

  for (pos=join->best_ref+join->const_tables,end=join->best_ref+idx ;
       pos != end ;
       pos++)
  {
    JOIN_TAB *join_tab= *pos;
    length+= join_tab->get_used_fieldlength();
  }
  return length;
}

Project: server

void *Virtual_tmp_table::operator new(size_t size, THD *thd) throw()
{
  return (Virtual_tmp_table *) alloc_root(thd->mem_root, size);
}

Project: server

bool Virtual_tmp_table::add(List<Spvar_definition> &field_list)
{
  /* Create all fields and calculate the total length of record */
  Spvar_definition *cdef;            /* column definition */
  List_iterator_fast<Spvar_definition> it(field_list);
  DBUG_ENTER("Virtual_tmp_table::add");
  while ((cdef= it++))
  {
    Field *tmp;
    if (!(tmp= cdef->make_field(s, in_use->mem_root, 0,
                             (uchar*) (f_maybe_null(cdef->pack_flag) ? "" : 0),
                             f_maybe_null(cdef->pack_flag) ? 1 : 0,
                             &cdef->field_name)))
      DBUG_RETURN(true);
     add(tmp);
  }
  DBUG_RETURN(false);
}

Project: server

init_sum_functions(Item_sum **func_ptr, Item_sum **end_ptr)
{
  for (; func_ptr != end_ptr ;func_ptr++)
  {
    if ((*func_ptr)->reset_and_add())
      return 1;
  }
  /* If rollup, calculate the upper sum levels */
  for ( ; *func_ptr ; func_ptr++)
  {
    if ((*func_ptr)->aggregator_add())
      return 1;
  }
  return 0;
}

Project: server

static int remove_dup_with_hash_index(THD *thd, TABLE *table,
				      uint field_count,
				      Field **first_field,
				      ulong key_length,
				      Item *having)
{
  uchar *key_buffer, *key_pos, *record=table->record[0];
  int error;
  handler *file= table->file;
  ulong extra_length= ALIGN_SIZE(key_length)-key_length;
  uint *field_lengths, *field_length;
  HASH hash;
  Field **ptr;
  DBUG_ENTER("remove_dup_with_hash_index");

  if (unlikely(!my_multi_malloc(MYF(MY_WME),
                                &key_buffer,
                                (uint) ((key_length + extra_length) *
                                        (long) file->stats.records),
                                &field_lengths,
                                (uint) (field_count*sizeof(*field_lengths)),
                                NullS)))
    DBUG_RETURN(1);

  for (ptr= first_field, field_length=field_lengths ; *ptr ; ptr++)
    (*field_length++)= (*ptr)->sort_length();

  if (unlikely(my_hash_init(&hash, &my_charset_bin,
                            (uint) file->stats.records, 0,
                            key_length, (my_hash_get_key) 0, 0, 0)))
  {
    my_free(key_buffer);
    DBUG_RETURN(1);
  }

  if (unlikely((error= file->ha_rnd_init(1))))
    goto err;

  key_pos=key_buffer;
  for (;;)
  {
    uchar *org_key_pos;
    if (unlikely(thd->check_killed()))
    {
      error=0;
      goto err;
    }
    if (unlikely((error= file->ha_rnd_next(record))))
    {
      if (error == HA_ERR_END_OF_FILE)
	break;
      goto err;
    }
    if (having && !having->val_int())
    {
      if (unlikely((error= file->ha_delete_row(record))))
	goto err;
      continue;
    }

    /* copy fields to key buffer */
    org_key_pos= key_pos;
    field_length=field_lengths;
    for (ptr= first_field ; *ptr ; ptr++)
    {
      (*ptr)->make_sort_key(key_pos, *field_length);
      key_pos+= (*ptr)->maybe_null() + *field_length++;
    }
    /* Check if it exists before */
    if (my_hash_search(&hash, org_key_pos, key_length))
    {
      /* Duplicated found ; Remove the row */
      if (unlikely((error= file->ha_delete_row(record))))
	goto err;
    }
    else
    {
      if (my_hash_insert(&hash, org_key_pos))
        goto err;
    }
    key_pos+=extra_length;
  }
  my_free(key_buffer);
  my_hash_free(&hash);
  file->extra(HA_EXTRA_NO_CACHE);
  (void) file->ha_rnd_end();
  DBUG_RETURN(0);

err:
  my_free(key_buffer);
  my_hash_free(&hash);
  file->extra(HA_EXTRA_NO_CACHE);
  (void) file->ha_rnd_end();
  if (unlikely(error))
    file->print_error(error,MYF(0));
  DBUG_RETURN(1);
}

Project: server

void JOIN::cache_const_exprs()
{
  bool cache_flag= FALSE;
  bool *analyzer_arg= &cache_flag;

  /* No need in cache if all tables are constant. */
  if (const_tables == table_count)
    return;

  if (conds)
    conds->compile(thd, &Item::cache_const_expr_analyzer, (uchar **)&analyzer_arg,
                  &Item::cache_const_expr_transformer, (uchar *)&cache_flag);
  cache_flag= FALSE;
  if (having)
    having->compile(thd, &Item::cache_const_expr_analyzer, (uchar **)&analyzer_arg,
                    &Item::cache_const_expr_transformer, (uchar *)&cache_flag);

  for (JOIN_TAB *tab= first_depth_first_tab(this); tab;
       tab= next_depth_first_tab(this, tab))
  {
    if (*tab->on_expr_ref)
    {
      cache_flag= FALSE;
      (*tab->on_expr_ref)->compile(thd, &Item::cache_const_expr_analyzer,
                                 (uchar **)&analyzer_arg,
                                 &Item::cache_const_expr_transformer,
                                 (uchar *)&cache_flag);
    }
  }
}

Project: server

void JOIN_TAB::remove_redundant_bnl_scan_conds()
{
  if (!(select_cond && cache_select && cache &&
        (cache->get_join_alg() == JOIN_CACHE::BNL_JOIN_ALG ||
         cache->get_join_alg() == JOIN_CACHE::BNLH_JOIN_ALG)))
    return;

  /*
    select->cond is not processed separately. This method assumes it is always
    the same as select_cond.
  */
  if (select && select->cond != select_cond)
    return;

  if (is_cond_and(select_cond))
  {
    List_iterator<Item> pushed_cond_li(*((Item_cond*) select_cond)->argument_list());
    Item *pushed_item;
    Item_cond_and *reduced_select_cond= new (join->thd->mem_root)
      Item_cond_and(join->thd);

    if (is_cond_and(cache_select->cond))
    {
      List_iterator<Item> scan_cond_li(*((Item_cond*) cache_select->cond)->argument_list());
      Item *scan_item;
      while ((pushed_item= pushed_cond_li++))
      {
        bool found_cond= false;
        scan_cond_li.rewind();
        while ((scan_item= scan_cond_li++))
        {
          if (pushed_item->eq(scan_item, 0))
          {
            found_cond= true;
            break;
          }
        }
        if (!found_cond)
          reduced_select_cond->add(pushed_item, join->thd->mem_root);
      }
    }
    else
    {
      while ((pushed_item= pushed_cond_li++))
      {
        if (!pushed_item->eq(cache_select->cond, 0))
          reduced_select_cond->add(pushed_item, join->thd->mem_root);
      }
    }

    /*
      JOIN_CACHE::check_match uses JOIN_TAB::select->cond instead of
      JOIN_TAB::select_cond. set_cond() sets both pointers.
    */
    if (reduced_select_cond->argument_list()->is_empty())
      set_cond(NULL);
    else if (reduced_select_cond->argument_list()->elements == 1)
      set_cond(reduced_select_cond->argument_list()->head());
    else
    {
      reduced_select_cond->quick_fix_field();
      set_cond(reduced_select_cond);
    }
  }
  else if (select_cond->eq(cache_select->cond, 0))
    set_cond(NULL);
}

Project: server

static void print_join(THD *thd,
                       table_map eliminated_tables,
                       String *str,
                       List<TABLE_LIST> *tables,
                       enum_query_type query_type)
{
  /* List is reversed => we should reverse it before using */
  List_iterator_fast<TABLE_LIST> ti(*tables);
  TABLE_LIST **table;
  DBUG_ENTER("print_join");

  /*
    If the QT_NO_DATA_EXPANSION flag is specified, we print the
    original table list, including constant tables that have been
    optimized away, as the constant tables may be referenced in the
    expression printed by Item_field::print() when this flag is given.
    Otherwise, only non-const tables are printed.

    Example:

    Original SQL:
    select * from (select 1) t

    Printed without QT_NO_DATA_EXPANSION:
    select '1' AS `1` from dual

    Printed with QT_NO_DATA_EXPANSION:
    select `t`.`1` from (select 1 AS `1`) `t`
  */
  const bool print_const_tables= (query_type & QT_NO_DATA_EXPANSION);
  size_t tables_to_print= 0;

  for (TABLE_LIST *t= ti++; t ; t= ti++)
  {
    /* See comment in print_table_array() about the second condition */
    if (print_const_tables || !t->optimized_away)
      if (!is_eliminated_table(eliminated_tables, t))
        tables_to_print++;
  }
  if (tables_to_print == 0)
  {
    str->append(STRING_WITH_LEN("dual"));
    DBUG_VOID_RETURN;                   // all tables were optimized away
  }
  ti.rewind();

  if (!(table= static_cast<TABLE_LIST **>(thd->alloc(sizeof(TABLE_LIST*) *
                                                     tables_to_print))))
    DBUG_VOID_RETURN;                   // out of memory

  TABLE_LIST *tmp, **t= table + (tables_to_print - 1);
  while ((tmp= ti++))
  {
    if (tmp->optimized_away && !print_const_tables)
      continue;
    if (is_eliminated_table(eliminated_tables, tmp))
      continue;
    *t--= tmp;
  }

  DBUG_ASSERT(tables->elements >= 1);
  /*
    Assert that the first table in the list isn't eliminated. This comes from
    the fact that the first table can't be inner table of an outer join.
  */
  DBUG_ASSERT(!eliminated_tables || 
              !(((*table)->table && ((*table)->table->map & eliminated_tables)) ||
                ((*table)->nested_join && !((*table)->nested_join->used_tables &
                                           ~eliminated_tables))));
  /* 
    If the first table is a semi-join nest, swap it with something that is
    not a semi-join nest.
  */
  if ((*table)->sj_inner_tables)
  {
    TABLE_LIST **end= table + tables_to_print;
    for (TABLE_LIST **t2= table; t2!=end; t2++)
    {
      if (!(*t2)->sj_inner_tables)
      {
        tmp= *t2;
        *t2= *table;
        *table= tmp;
        break;
      }
    }
  }
  print_table_array(thd, eliminated_tables, str, table, 
                    table +  tables_to_print, query_type);
  DBUG_VOID_RETURN;
}

Project: server

Field *Item_sum::create_tmp_field(bool group, TABLE *table)
{
  Field *UNINIT_VAR(new_field);
  MEM_ROOT *mem_root= table->in_use->mem_root;

  switch (cmp_type()) {
  case REAL_RESULT:
  {
    new_field= new (mem_root)
      Field_double(max_char_length(), maybe_null, &name, decimals, TRUE);
    break;
  }
  case INT_RESULT:
  case TIME_RESULT:
  case DECIMAL_RESULT:
  case STRING_RESULT:
    new_field= tmp_table_field_from_field_type(table);
    break;
  case ROW_RESULT:
    // This case should never be choosen
    DBUG_ASSERT(0);
    new_field= 0;
    break;
  }
  if (new_field)
    new_field->init(table);
  return new_field;
}

Project: server

static bool check_interleaving_with_nj(JOIN_TAB *next_tab)
{
  TABLE_LIST *next_emb= next_tab->table->pos_in_table_list->embedding;
  JOIN *join= next_tab->join;

  if (join->cur_embedding_map & ~next_tab->embedding_map)
  {
    /* 
      next_tab is outside of the "pair of brackets" we're currently in.
      Cannot add it.
    */
    return TRUE;
  }
   
  /*
    Do update counters for "pairs of brackets" that we've left (marked as
    X,Y,Z in the above picture)
  */
  for (;next_emb && next_emb != join->emb_sjm_nest; next_emb= next_emb->embedding)
  {
    if (!next_emb->sj_on_expr)
    {
      next_emb->nested_join->counter++;
      if (next_emb->nested_join->counter == 1)
      {
        /* 
          next_emb is the first table inside a nested join we've "entered". In
          the picture above, we're looking at the 'X' bracket. Don't exit yet as
          X bracket might have Y pair bracket.
        */
        join->cur_embedding_map |= next_emb->nested_join->nj_map;
      }
      
      if (next_emb->nested_join->n_tables !=
          next_emb->nested_join->counter)
        break;

      /*
        We're currently at Y or Z-bracket as depicted in the above picture.
        Mark that we've left it and continue walking up the brackets hierarchy.
      */
      join->cur_embedding_map &= ~next_emb->nested_join->nj_map;
    }
  }
  return FALSE;
}

Project: server

get_store_key(THD *thd, KEYUSE *keyuse, table_map used_tables,
	      KEY_PART_INFO *key_part, uchar *key_buff, uint maybe_null)
{
  if (!((~used_tables) & keyuse->used_tables))		// if const item
  {
    return new store_key_const_item(thd,
				    key_part->field,
				    key_buff + maybe_null,
				    maybe_null ? key_buff : 0,
				    key_part->length,
				    keyuse->val);
  }
  else if (keyuse->val->type() == Item::FIELD_ITEM ||
           (keyuse->val->type() == Item::REF_ITEM &&
	    ((((Item_ref*)keyuse->val)->ref_type() == Item_ref::OUTER_REF &&
              (*(Item_ref**)((Item_ref*)keyuse->val)->ref)->ref_type() ==
              Item_ref::DIRECT_REF) || 
             ((Item_ref*)keyuse->val)->ref_type() == Item_ref::VIEW_REF) &&
            keyuse->val->real_item()->type() == Item::FIELD_ITEM))
    return new store_key_field(thd,
			       key_part->field,
			       key_buff + maybe_null,
			       maybe_null ? key_buff : 0,
			       key_part->length,
			       ((Item_field*) keyuse->val->real_item())->field,
			       keyuse->val->real_item()->full_name());

  return new store_key_item(thd,
			    key_part->field,
			    key_buff + maybe_null,
			    maybe_null ? key_buff : 0,
			    key_part->length,
			    keyuse->val, FALSE);
}

Project: server

bool JOIN_TAB::keyuse_is_valid_for_access_in_chosen_plan(JOIN *join,
                                                         KEYUSE *keyuse)
{
  if (!access_from_tables_is_allowed(keyuse->used_tables, 
                                     join->sjm_lookup_tables))
    return false;
  if (join->sjm_scan_tables & table->map)
    return true;
  table_map keyuse_sjm_scan_tables= keyuse->used_tables &
                                    join->sjm_scan_tables;
  if (!keyuse_sjm_scan_tables)
    return true;
  uint sjm_tab_nr= 0;
  while (!(keyuse_sjm_scan_tables & table_map(1) << sjm_tab_nr))
    sjm_tab_nr++;
  JOIN_TAB *sjm_tab= join->map2table[sjm_tab_nr];
  TABLE_LIST *emb_sj_nest= sjm_tab->emb_sj_nest;    
  if (!(emb_sj_nest->sj_mat_info && emb_sj_nest->sj_mat_info->is_used &&
        emb_sj_nest->sj_mat_info->is_sj_scan))
    return true;
  st_select_lex *sjm_sel= emb_sj_nest->sj_subq_pred->unit->first_select(); 
  for (uint i= 0; i < sjm_sel->item_list.elements; i++)
  {
    DBUG_ASSERT(sjm_sel->ref_pointer_array[i]->real_item()->type() == Item::FIELD_ITEM);
    if (keyuse->val->real_item()->type() == Item::FIELD_ITEM)
    {
      Field *field = ((Item_field*)sjm_sel->ref_pointer_array[i]->real_item())->field;
      if (field->eq(((Item_field*)keyuse->val->real_item())->field))
        return true;
    }
  }
  return false; 
}

Project: server

void compute_part_of_sort_key_for_equals(JOIN *join, TABLE *table,
                                         Item_field *item_field,
                                         key_map *col_keys)
{
  col_keys->clear_all();
  col_keys->merge(item_field->field->part_of_sortkey);
  
  if (!optimizer_flag(join->thd, OPTIMIZER_SWITCH_ORDERBY_EQ_PROP))
    return;

  Item_equal *item_eq= NULL;

  if (item_field->item_equal)
  {
    /* 
      The item_field is from ORDER structure, but it already has an item_equal
      pointer set (UseMultipleEqualitiesToRemoveTempTable code have set it)
    */
    item_eq= item_field->item_equal;
  }
  else
  {
    /* 
      Walk through join's muliple equalities and find the one that contains
      item_field.
    */
    if (!join->cond_equal)
      return;
    table_map needed_tbl_map= item_field->used_tables() | table->map;
    List_iterator<Item_equal> li(join->cond_equal->current_level);
    Item_equal *cur_item_eq;
    while ((cur_item_eq= li++))
    {
      if ((cur_item_eq->used_tables() & needed_tbl_map) &&
          cur_item_eq->contains(item_field->field))
      {
        item_eq= cur_item_eq;
        item_field->item_equal= item_eq; // Save the pointer to our Item_equal.
        break;
      }
    }
  }
  
  if (item_eq)
  {
    Item_equal_fields_iterator it(*item_eq);
    Item *item;
    /* Loop through other members that belong to table table */
    while ((item= it++))
    {
      if (item->type() == Item::FIELD_ITEM &&
          ((Item_field*)item)->field->table == table)
      {
        col_keys->merge(((Item_field*)item)->field->part_of_sortkey);
      }
    }
  }
}

Project: server

end_update(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
	   bool end_of_records)
{
  TABLE *const table= join_tab->table;
  ORDER   *group;
  int	  error;
  DBUG_ENTER("end_update");

  if (end_of_records)
    DBUG_RETURN(NESTED_LOOP_OK);

  join->found_records++;
  copy_fields(join_tab->tmp_table_param);	// Groups are copied twice.
  /* Make a key of group index */
  for (group=table->group ; group ; group=group->next)
  {
    Item *item= *group->item;
    if (group->fast_field_copier_setup != group->field)
    {
      DBUG_PRINT("info", ("new setup %p -> %p",
                          group->fast_field_copier_setup,
                          group->field));
      group->fast_field_copier_setup= group->field;
      group->fast_field_copier_func=
        item->setup_fast_field_copier(group->field);
    }
    item->save_org_in_field(group->field, group->fast_field_copier_func);
    /* Store in the used key if the field was 0 */
    if (item->maybe_null)
      group->buff[-1]= (char) group->field->is_null();
  }
  if (!table->file->ha_index_read_map(table->record[1],
                                      join_tab->tmp_table_param->group_buff,
                                      HA_WHOLE_KEY,
                                      HA_READ_KEY_EXACT))
  {						/* Update old record */
    restore_record(table,record[1]);
    update_tmptable_sum_func(join->sum_funcs,table);
    if (unlikely((error= table->file->ha_update_tmp_row(table->record[1],
                                                        table->record[0]))))
    {
      table->file->print_error(error,MYF(0));	/* purecov: inspected */
      DBUG_RETURN(NESTED_LOOP_ERROR);            /* purecov: inspected */
    }
    goto end;
  }

  init_tmptable_sum_functions(join->sum_funcs);
  if (unlikely(copy_funcs(join_tab->tmp_table_param->items_to_copy,
                          join->thd)))
    DBUG_RETURN(NESTED_LOOP_ERROR);           /* purecov: inspected */
  if (unlikely((error= table->file->ha_write_tmp_row(table->record[0]))))
  {
    if (create_internal_tmp_table_from_heap(join->thd, table,
                                       join_tab->tmp_table_param->start_recinfo,
                                            &join_tab->tmp_table_param->recinfo,
                                            error, 0, NULL))
      DBUG_RETURN(NESTED_LOOP_ERROR);            // Not a table_is_full error
    /* Change method to update rows */
    if (unlikely((error= table->file->ha_index_init(0, 0))))
    {
      table->file->print_error(error, MYF(0));
      DBUG_RETURN(NESTED_LOOP_ERROR);
    }

    join_tab->aggr->set_write_func(end_unique_update);
  }
  join_tab->send_records++;
end:
  if (unlikely(join->thd->check_killed()))
  {
    DBUG_RETURN(NESTED_LOOP_KILLED);             /* purecov: inspected */
  }
  DBUG_RETURN(NESTED_LOOP_OK);
}

Project: server

JOIN::create_postjoin_aggr_table(JOIN_TAB *tab, List<Item> *table_fields,
                                 ORDER *table_group,
                                 bool save_sum_fields,
                                 bool distinct,
                                 bool keep_row_order)
{
  DBUG_ENTER("JOIN::create_postjoin_aggr_table");
  THD_STAGE_INFO(thd, stage_creating_tmp_table);

  /*
    Pushing LIMIT to the post-join temporary table creation is not applicable
    when there is ORDER BY or GROUP BY or there is no GROUP BY, but
    there are aggregate functions, because in all these cases we need
    all result rows.
  */
  ha_rows table_rows_limit= ((order == NULL || skip_sort_order) &&
                              !table_group &&
                              !select_lex->with_sum_func) ? select_limit
                                                          : HA_POS_ERROR;

  if (!(tab->tmp_table_param= new TMP_TABLE_PARAM(tmp_table_param)))
    DBUG_RETURN(true);
  if (tmp_table_keep_current_rowid)
    add_fields_for_current_rowid(tab, table_fields);
  tab->tmp_table_param->skip_create_table= true;
  TABLE* table= create_tmp_table(thd, tab->tmp_table_param, *table_fields,
                                 table_group, distinct,
                                 save_sum_fields, select_options, table_rows_limit, 
                                 &empty_clex_str, true, keep_row_order);
  if (!table)
    DBUG_RETURN(true);
  tmp_table_param.using_outer_summary_function=
    tab->tmp_table_param->using_outer_summary_function;
  tab->join= this;
  DBUG_ASSERT(tab > tab->join->join_tab || !top_join_tab_count || !tables_list);
  if (tab > join_tab)
    (tab - 1)->next_select= sub_select_postjoin_aggr;
  if (!(tab->aggr= new (thd->mem_root) AGGR_OP(tab)))
    goto err;
  tab->table= table;
  table->reginfo.join_tab= tab;

  /* if group or order on first table, sort first */
  if ((group_list && simple_group) ||
      (implicit_grouping && select_lex->have_window_funcs()))
  {
    DBUG_PRINT("info",("Sorting for group"));
    THD_STAGE_INFO(thd, stage_sorting_for_group);

    if (ordered_index_usage != ordered_index_group_by &&
        !only_const_tables() &&
        (join_tab + const_tables)->type != JT_CONST && // Don't sort 1 row
        !implicit_grouping &&
        add_sorting_to_table(join_tab + const_tables, group_list))
      goto err;

    if (alloc_group_fields(this, group_list))
      goto err;
    if (make_sum_func_list(all_fields, fields_list, true))
      goto err;
    if (prepare_sum_aggregators(sum_funcs,
                                !(tables_list && 
                                  join_tab->is_using_agg_loose_index_scan())))
      goto err;
    if (setup_sum_funcs(thd, sum_funcs))
      goto err;
    group_list= NULL;
  }
  else
  {
    if (make_sum_func_list(all_fields, fields_list, false))
      goto err;
    if (prepare_sum_aggregators(sum_funcs,
                                !join_tab->is_using_agg_loose_index_scan()))
      goto err;
    if (setup_sum_funcs(thd, sum_funcs))
      goto err;

    if (!group_list && !table->distinct && order && simple_order &&
        tab == join_tab + const_tables)
    {
      DBUG_PRINT("info",("Sorting for order"));
      THD_STAGE_INFO(thd, stage_sorting_for_order);

      if (ordered_index_usage != ordered_index_order_by &&
          !only_const_tables() &&
          add_sorting_to_table(join_tab + const_tables, order))
        goto err;
      order= NULL;
    }
  }

  DBUG_RETURN(false);

err:
  if (table != NULL)
    free_tmp_table(thd, table);
  DBUG_RETURN(true);
}

Project: server

JOIN_TAB *first_explain_order_tab(JOIN* join)
{
  JOIN_TAB* tab;
  tab= join->join_tab;
  if (!tab)
    return NULL; /* Can happen when when the tables were optimized away */
  return (tab->bush_children) ? tab->bush_children->start : tab;
}

Project: server

end_send(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
	 bool end_of_records)
{
  DBUG_ENTER("end_send");
  /*
    When all tables are const this function is called with jointab == NULL.
    This function shouldn't be called for the first join_tab as it needs
    to get fields from previous tab.
  */
  DBUG_ASSERT(join_tab == NULL || join_tab != join->join_tab);
  //TODO pass fields via argument
  List<Item> *fields= join_tab ? (join_tab-1)->fields : join->fields;

  if (!end_of_records)
  {
    if (join->table_count &&
        join->join_tab->is_using_loose_index_scan())
    {
      /* Copy non-aggregated fields when loose index scan is used. */
      copy_fields(&join->tmp_table_param);
    }
    if (join->having && join->having->val_int() == 0)
      DBUG_RETURN(NESTED_LOOP_OK);               // Didn't match having
    if (join->procedure)
    {
      if (join->procedure->send_row(join->procedure_fields_list))
        DBUG_RETURN(NESTED_LOOP_ERROR);
      DBUG_RETURN(NESTED_LOOP_OK);
    }
    if (join->do_send_rows)
    {
      int error;
      /* result < 0 if row was not accepted and should not be counted */
      if (unlikely((error= join->result->send_data(*fields))))
      {
        if (error > 0)
          DBUG_RETURN(NESTED_LOOP_ERROR);
        // error < 0 => duplicate row
        join->duplicate_rows++;
      }
    }

    ++join->send_records;
    if (join->send_records >= join->unit->select_limit_cnt &&
        !join->do_send_rows)
    {
      /*
        If we have used Priority Queue for optimizing order by with limit,
        then stop here, there are no more records to consume.
        When this optimization is used, end_send is called on the next
        join_tab.
      */
      if (join->order &&
          join->select_options & OPTION_FOUND_ROWS &&
          join_tab > join->join_tab &&
          (join_tab - 1)->filesort && (join_tab - 1)->filesort->using_pq)
      {
        DBUG_PRINT("info", ("filesort NESTED_LOOP_QUERY_LIMIT"));
        DBUG_RETURN(NESTED_LOOP_QUERY_LIMIT);
      }
    }
    if (join->send_records >= join->unit->select_limit_cnt &&
	join->do_send_rows)
    {
      if (join->select_options & OPTION_FOUND_ROWS)
      {
	JOIN_TAB *jt=join->join_tab;
	if ((join->table_count == 1) && !join->sort_and_group
	    && !join->send_group_parts && !join->having && !jt->select_cond &&
	    !(jt->select && jt->select->quick) &&
	    (jt->table->file->ha_table_flags() & HA_STATS_RECORDS_IS_EXACT) &&
            (jt->ref.key < 0))
	{
	  /* Join over all rows in table;  Return number of found rows */
	  TABLE *table=jt->table;

	  if (jt->filesort_result)                     // If filesort was used
	  {
	    join->send_records= jt->filesort_result->found_rows;
	  }
	  else
	  {
	    table->file->info(HA_STATUS_VARIABLE);
	    join->send_records= table->file->stats.records;
	  }
	}
	else 
	{
	  join->do_send_rows= 0;
	  if (join->unit->fake_select_lex)
	    join->unit->fake_select_lex->select_limit= 0;
	  DBUG_RETURN(NESTED_LOOP_OK);
	}
      }
      DBUG_RETURN(NESTED_LOOP_QUERY_LIMIT);      // Abort nicely
    }
    else if (join->send_records >= join->fetch_limit)
    {
      /*
        There is a server side cursor and all rows for
        this fetch request are sent.
      */
      DBUG_RETURN(NESTED_LOOP_CURSOR_LIMIT);
    }
  }
  else
  {
    if (join->procedure && join->procedure->end_of_records())
      DBUG_RETURN(NESTED_LOOP_ERROR);
  }
  DBUG_RETURN(NESTED_LOOP_OK);
}

Project: server

bool JOIN::prepare_stage2()
{
  bool res= TRUE;
  DBUG_ENTER("JOIN::prepare_stage2");

  /* Init join struct */
  count_field_types(select_lex, &tmp_table_param, all_fields, 0);
  this->group= group_list != 0;

  if (tmp_table_param.sum_func_count && !group_list)
  {
    implicit_grouping= TRUE;
    // Result will contain zero or one row - ordering is meaningless
    order= NULL;
  }

#ifdef RESTRICTED_GROUP
  if (implicit_grouping)
  {
    my_message(ER_WRONG_SUM_SELECT,ER_THD(thd, ER_WRONG_SUM_SELECT),MYF(0));
    goto err;
  }
#endif
  if (select_lex->olap == ROLLUP_TYPE && rollup_init())
    goto err;
  if (alloc_func_list())
    goto err;

  res= FALSE;
err:
  DBUG_RETURN(res);				/* purecov: inspected */
}

Project: server

add_key_field(JOIN *join,
              KEY_FIELD **key_fields,uint and_level, Item_bool_func *cond,
              Field *field, bool eq_func, Item **value, uint num_values,
              table_map usable_tables, SARGABLE_PARAM **sargables,
              uint row_col_no= 0)
{
  uint optimize= 0;  
  if (eq_func &&
      ((join->is_allowed_hash_join_access() &&
        field->hash_join_is_possible() && 
        !(field->table->pos_in_table_list->is_materialized_derived() &&
          field->table->is_created())) ||
       (field->table->pos_in_table_list->is_materialized_derived() &&
        !field->table->is_created() && !(field->flags & BLOB_FLAG))))
  {
    optimize= KEY_OPTIMIZE_EQ;
  }   
  else if (!(field->flags & PART_KEY_FLAG))
  {
    // Don't remove column IS NULL on a LEFT JOIN table
    if (eq_func && (*value)->type() == Item::NULL_ITEM &&
        field->table->maybe_null && !field->null_ptr)
    {
      optimize= KEY_OPTIMIZE_EXISTS;
      DBUG_ASSERT(num_values == 1);
    }
  }
  if (optimize != KEY_OPTIMIZE_EXISTS)
  {
    table_map used_tables=0;
    bool optimizable=0;
    for (uint i=0; i<num_values; i++)
    {
      Item *curr_val; 
      if (row_col_no && value[i]->real_item()->type() == Item::ROW_ITEM)
      {
        Item_row *value_tuple= (Item_row *) (value[i]->real_item());
        curr_val= value_tuple->element_index(row_col_no - 1);
      }
      else
        curr_val= value[i];
      table_map value_used_tables= curr_val->used_tables();
      used_tables|= value_used_tables;
      if (!(value_used_tables & (field->table->map | RAND_TABLE_BIT)))
        optimizable=1;
    }
    if (!optimizable)
      return;
    if (!(usable_tables & field->table->map))
    {
      if (!eq_func || (*value)->type() != Item::NULL_ITEM ||
          !field->table->maybe_null || field->null_ptr)
	return;					// Can't use left join optimize
      optimize= KEY_OPTIMIZE_EXISTS;
    }
    else
    {
      JOIN_TAB *stat=field->table->reginfo.join_tab;
      key_map possible_keys=field->get_possible_keys();
      possible_keys.intersect(field->table->keys_in_use_for_query);
      stat[0].keys.merge(possible_keys);             // Add possible keys

      /*
	Save the following cases:
	Field op constant
	Field LIKE constant where constant doesn't start with a wildcard
	Field = field2 where field2 is in a different table
	Field op formula
	Field IS NULL
	Field IS NOT NULL
         Field BETWEEN ...
         Field IN ...
      */
      if (field->flags & PART_KEY_FLAG)
        stat[0].key_dependent|=used_tables;

      bool is_const=1;
      for (uint i=0; i<num_values; i++)
      {
        Item *curr_val;
        if (row_col_no && value[i]->real_item()->type() == Item::ROW_ITEM)
	{
          Item_row *value_tuple= (Item_row *) (value[i]->real_item());
          curr_val= value_tuple->element_index(row_col_no - 1);
        }
        else
          curr_val= value[i];
        if (!(is_const&= curr_val->const_item()))
          break;
      }
      if (is_const)
      {
        stat[0].const_keys.merge(possible_keys);
        bitmap_set_bit(&field->table->cond_set, field->field_index);
      }
      else if (!eq_func)
      {
        /* 
          Save info to be able check whether this predicate can be 
          considered as sargable for range analisis after reading const tables.
          We do not save info about equalities as update_const_equal_items
          will take care of updating info on keys from sargable equalities. 
        */
        (*sargables)--;
        (*sargables)->field= field;
        (*sargables)->arg_value= value;
        (*sargables)->num_values= num_values;
      }
      if (!eq_func) // eq_func is NEVER true when num_values > 1
        return;
    }
  }
  /*
    For the moment eq_func is always true. This slot is reserved for future
    extensions where we want to remembers other things than just eq comparisons
  */
  DBUG_ASSERT(eq_func);
  /* Store possible eq field */
  (*key_fields)->field=		field;
  (*key_fields)->eq_func=	eq_func;
  (*key_fields)->val=		*value;
  (*key_fields)->cond=          cond;
  (*key_fields)->level=         and_level;
  (*key_fields)->optimize=      optimize;
  /*
    If the condition we are analyzing is NULL-rejecting and at least
    one side of the equalities is NULLable, mark the KEY_FIELD object as
    null-rejecting. This property is used by:
    - add_not_null_conds() to add "column IS NOT NULL" conditions
    - best_access_path() to produce better estimates for NULL-able unique keys.
  */
  {
    if ((cond->functype() == Item_func::EQ_FUNC ||
         cond->functype() == Item_func::MULT_EQUAL_FUNC) &&
        ((*value)->maybe_null || field->real_maybe_null()))
      (*key_fields)->null_rejecting= true;
    else
      (*key_fields)->null_rejecting= false;
  }
  (*key_fields)->cond_guard= NULL;

  (*key_fields)->sj_pred_no= get_semi_join_select_list_index(field);
  (*key_fields)++;
}

Project: server

JOIN_TAB *next_depth_first_tab(JOIN* join, JOIN_TAB* tab)
{
  /* If we're inside SJM nest and have reached its end, get out */
  if (tab->last_leaf_in_bush)
    return tab->bush_root_tab;
  
  /* Move to next tab in the array we're traversing */
  tab++;
  
  if (tab == join->join_tab +join->top_join_tab_count)
    return NULL; /* Outside SJM nest and reached EOF */

  if (tab->bush_children)
    return tab->bush_children->start;

  return tab;
}

Project: server

void JOIN::exec_inner()
{
  List<Item> *columns_list= &fields_list;
  DBUG_ENTER("JOIN::exec_inner");
  DBUG_ASSERT(optimization_state == JOIN::OPTIMIZATION_DONE);

  THD_STAGE_INFO(thd, stage_executing);

  /*
    Enable LIMIT ROWS EXAMINED during query execution if:
    (1) This JOIN is the outermost query (not a subquery or derived table)
        This ensures that the limit is enabled when actual execution begins, and
        not if a subquery is evaluated during optimization of the outer query.
    (2) This JOIN is not the result of a UNION. In this case do not apply the
        limit in order to produce the partial query result stored in the
        UNION temp table.
  */
  if (!select_lex->outer_select() &&                            // (1)
      select_lex != select_lex->master_unit()->fake_select_lex) // (2)
    thd->lex->set_limit_rows_examined();

  if (procedure)
  {
    procedure_fields_list= fields_list;
    if (procedure->change_columns(thd, procedure_fields_list) ||
	result->prepare(procedure_fields_list, unit))
    {
      thd->set_examined_row_count(0);
      thd->limit_found_rows= 0;
      DBUG_VOID_RETURN;
    }
    columns_list= &procedure_fields_list;
  }
  if (result->prepare2(this))
    DBUG_VOID_RETURN;

  if (!tables_list && (table_count || !select_lex->with_sum_func) &&
      !select_lex->have_window_funcs())
  {                                           // Only test of functions
    if (select_options & SELECT_DESCRIBE)
      select_describe(this, FALSE, FALSE, FALSE,
		      (zero_result_cause?zero_result_cause:"No tables used"));

    else
    {
      if (result->send_result_set_metadata(*columns_list,
                                           Protocol::SEND_NUM_ROWS |
                                           Protocol::SEND_EOF))
      {
        DBUG_VOID_RETURN;
      }

      /*
        We have to test for 'conds' here as the WHERE may not be constant
        even if we don't have any tables for prepared statements or if
        conds uses something like 'rand()'.
        If the HAVING clause is either impossible or always true, then
        JOIN::having is set to NULL by optimize_cond.
        In this case JOIN::exec must check for JOIN::having_value, in the
        same way it checks for JOIN::cond_value.
      */
      DBUG_ASSERT(error == 0);
      if (cond_value != Item::COND_FALSE &&
          having_value != Item::COND_FALSE &&
          (!conds || conds->val_int()) &&
          (!having || having->val_int()))
      {
	if (do_send_rows &&
            (procedure ? (procedure->send_row(procedure_fields_list) ||
             procedure->end_of_records()) : result->send_data(fields_list)> 0))
	  error= 1;
	else
	  send_records= ((select_options & OPTION_FOUND_ROWS) ? 1 :
                         thd->get_sent_row_count());
      }
      else
        send_records= 0;
      if (likely(!error))
      {
        join_free();                      // Unlock all cursors
        error= (int) result->send_eof();
      }
    }
    /* Single select (without union) always returns 0 or 1 row */
    thd->limit_found_rows= send_records;
    thd->set_examined_row_count(0);
    DBUG_VOID_RETURN;
  }

  /*
    Evaluate expensive constant conditions that were not evaluated during
    optimization. Do not evaluate them for EXPLAIN statements as these
    condtions may be arbitrarily costly, and because the optimize phase
    might not have produced a complete executable plan for EXPLAINs.
  */
  if (!zero_result_cause &&
      exec_const_cond && !(select_options & SELECT_DESCRIBE) &&
      !exec_const_cond->val_int())
    zero_result_cause= "Impossible WHERE noticed after reading const tables";

  /* 
    We've called exec_const_cond->val_int(). This may have caused an error.
  */
  if (unlikely(thd->is_error()))
  {
    error= thd->is_error();
    DBUG_VOID_RETURN;
  }

  if (zero_result_cause)
  {
    if (select_lex->have_window_funcs() && send_row_on_empty_set())
    {
      /*
        The query produces just one row but it has window functions.

        The only way to compute the value of window function(s) is to
        run the entire window function computation step (there is no shortcut).
      */
      const_tables= table_count;
      first_select= sub_select_postjoin_aggr;
    }
    else
    {
      (void) return_zero_rows(this, result, select_lex->leaf_tables,
                              *columns_list,
			      send_row_on_empty_set(),
			      select_options,
			      zero_result_cause,
			      having ? having : tmp_having, all_fields);
      DBUG_VOID_RETURN;
    }
  }
  
  /*
    Evaluate all constant expressions with subqueries in the
    ORDER/GROUP clauses to make sure that all subqueries return a
    single row. The evaluation itself will trigger an error if that is
    not the case.
  */
  if (exec_const_order_group_cond.elements &&
      !(select_options & SELECT_DESCRIBE))
  {
    List_iterator_fast<Item> const_item_it(exec_const_order_group_cond);
    Item *cur_const_item;
    while ((cur_const_item= const_item_it++))
    {
      cur_const_item->val_str(); // This caches val_str() to Item::str_value
      if (unlikely(thd->is_error()))
      {
        error= thd->is_error();
        DBUG_VOID_RETURN;
      }
    }
  }

  if ((this->select_lex->options & OPTION_SCHEMA_TABLE) &&
      get_schema_tables_result(this, PROCESSED_BY_JOIN_EXEC))
    DBUG_VOID_RETURN;

  if (select_options & SELECT_DESCRIBE)
  {
    select_describe(this, need_tmp,
		    order != 0 && !skip_sort_order,
		    select_distinct,
                    !table_count ? "No tables used" : NullS);
    DBUG_VOID_RETURN;
  }
  else
  {
    /* it's a const select, materialize it. */
    select_lex->mark_const_derived(zero_result_cause);
  }

  /*
    Initialize examined rows here because the values from all join parts
    must be accumulated in examined_row_count. Hence every join
    iteration must count from zero.
  */
  join_examined_rows= 0;

  /* XXX: When can we have here thd->is_error() not zero? */
  if (unlikely(thd->is_error()))
  {
    error= thd->is_error();
    DBUG_VOID_RETURN;
  }

  THD_STAGE_INFO(thd, stage_sending_data);
  DBUG_PRINT("info", ("%s", thd->proc_info));
  result->send_result_set_metadata(
                 procedure ? procedure_fields_list : *fields,
                 Protocol::SEND_NUM_ROWS | Protocol::SEND_EOF);

  error= result->view_structure_only() ? false : do_select(this, procedure);
  /* Accumulate the counts from all join iterations of all join parts. */
  thd->inc_examined_row_count(join_examined_rows);
  DBUG_PRINT("counts", ("thd->examined_row_count: %lu",
                        (ulong) thd->get_examined_row_count()));

  DBUG_VOID_RETURN;
}

Project: server

void vers_select_conds_t::print(String *str, enum_query_type query_type) const
{
  switch (orig_type) {
  case SYSTEM_TIME_UNSPECIFIED:
    break;
  case SYSTEM_TIME_AS_OF:
    start.print(str, query_type, STRING_WITH_LEN(" FOR SYSTEM_TIME AS OF "));
    break;
  case SYSTEM_TIME_FROM_TO:
    start.print(str, query_type, STRING_WITH_LEN(" FOR SYSTEM_TIME FROM "));
    end.print(str, query_type, STRING_WITH_LEN(" TO "));
    break;
  case SYSTEM_TIME_BETWEEN:
    start.print(str, query_type, STRING_WITH_LEN(" FOR SYSTEM_TIME BETWEEN "));
    end.print(str, query_type, STRING_WITH_LEN(" AND "));
    break;
  case SYSTEM_TIME_BEFORE:
  case SYSTEM_TIME_HISTORY:
    DBUG_ASSERT(0);
    break;
  case SYSTEM_TIME_ALL:
    str->append(" FOR SYSTEM_TIME ALL");
    break;
  }
}

Project: server

void TABLE_LIST::print(THD *thd, table_map eliminated_tables, String *str, 
                       enum_query_type query_type)
{
  if (nested_join)
  {
    str->append('(');
    print_join(thd, eliminated_tables, str, &nested_join->join_list, query_type);
    str->append(')');
  }
  else if (jtbm_subselect)
  {
    if (jtbm_subselect->engine->engine_type() ==
          subselect_engine::SINGLE_SELECT_ENGINE)
    {
      /* 
        We get here when conversion into materialization didn't finish (this
        happens when
        - The subquery is a degenerate case which produces 0 or 1 record
        - subquery's optimization didn't finish because of @@max_join_size
          limits
        - ... maybe some other cases like this 
      */
      str->append(STRING_WITH_LEN(" <materialize> ("));
      jtbm_subselect->engine->print(str, query_type);
      str->append(')');
    }
    else
    {
      str->append(STRING_WITH_LEN(" <materialize> ("));
      subselect_hash_sj_engine *hash_engine;
      hash_engine= (subselect_hash_sj_engine*)jtbm_subselect->engine;
      hash_engine->materialize_engine->print(str, query_type);
      str->append(')');
    }
  }
  else
  {
    const char *cmp_name;                         // Name to compare with alias
    if (view_name.str)
    {
      // A view

      if (!(belong_to_view &&
            belong_to_view->compact_view_format))
      {
        append_identifier(thd, str, &view_db);
        str->append('.');
      }
      append_identifier(thd, str, &view_name);
      cmp_name= view_name.str;
    }
    else if (derived)
    {
      if (!is_with_table())
      {
        // A derived table
        str->append('(');
        derived->print(str, query_type);
        str->append(')');
        cmp_name= "";                               // Force printing of alias
      }
      else
      {
        append_identifier(thd, str, &table_name);
        cmp_name= table_name.str;
      }
    }
    else
    {
      // A normal table

      if (!(belong_to_view &&
            belong_to_view->compact_view_format))
      {
        append_identifier(thd, str, &db);
        str->append('.');
      }
      if (schema_table)
      {
        append_identifier(thd, str, &schema_table_name);
        cmp_name= schema_table_name.str;
      }
      else
      {
        append_identifier(thd, str, &table_name);
        cmp_name= table_name.str;
      }
#ifdef WITH_PARTITION_STORAGE_ENGINE
      if (partition_names && partition_names->elements)
      {
        int i, num_parts= partition_names->elements;
        List_iterator<String> name_it(*(partition_names));
        str->append(STRING_WITH_LEN(" PARTITION ("));
        for (i= 1; i <= num_parts; i++)
        {
          String *name= name_it++;
          append_identifier(thd, str, name->c_ptr(), name->length());
          if (i != num_parts)
            str->append(',');
        }
        str->append(')');
      }
#endif /* WITH_PARTITION_STORAGE_ENGINE */
    }
    if (table && table->versioned())
      vers_conditions.print(str, query_type);

    if (my_strcasecmp(table_alias_charset, cmp_name, alias.str))
    {
      char t_alias_buff[MAX_ALIAS_NAME];
      LEX_CSTRING t_alias= alias;

      str->append(' ');
      if (lower_case_table_names == 1)
      {
        if (alias.str && alias.str[0])
        {
          strmov(t_alias_buff, alias.str);
          t_alias.length= my_casedn_str(files_charset_info, t_alias_buff);
          t_alias.str= t_alias_buff;
        }
      }

      append_identifier(thd, str, &t_alias);
    }

    if (index_hints)
    {
      List_iterator<Index_hint> it(*index_hints);
      Index_hint *hint;

      while ((hint= it++))
      {
        str->append (STRING_WITH_LEN(" "));
        hint->print (thd, str);
      }
    }
  }
}

Project: server

make_join_statistics(JOIN *join, List<TABLE_LIST> &tables_list,
                     DYNAMIC_ARRAY *keyuse_array)
{
  int error= 0;
  TABLE *UNINIT_VAR(table); /* inited in all loops */
  uint i,table_count,const_count,key;
  table_map found_const_table_map, all_table_map;
  key_map const_ref, eq_part;
  bool has_expensive_keyparts;
  TABLE **table_vector;
  JOIN_TAB *stat,*stat_end,*s,**stat_ref, **stat_vector;
  KEYUSE *keyuse,*start_keyuse;
  table_map outer_join=0;
  table_map no_rows_const_tables= 0;
  SARGABLE_PARAM *sargables= 0;
  List_iterator<TABLE_LIST> ti(tables_list);
  TABLE_LIST *tables;
  DBUG_ENTER("make_join_statistics");

  table_count=join->table_count;

  /*
    best_positions is ok to allocate with alloc() as we copy things to it with
    memcpy()
  */

  if (!multi_alloc_root(join->thd->mem_root,
                        &stat, sizeof(JOIN_TAB)*(table_count),
                        &stat_ref, sizeof(JOIN_TAB*)* MAX_TABLES,
                        &stat_vector, sizeof(JOIN_TAB*)* (table_count +1),
                        &table_vector, sizeof(TABLE*)*(table_count*2),
                        &join->positions, sizeof(POSITION)*(table_count + 1),
                        &join->best_positions,
                        sizeof(POSITION)*(table_count + 1),
                        NullS))
    DBUG_RETURN(1);

  /* The following should be optimized to only clear critical things */
  bzero((void*)stat, sizeof(JOIN_TAB)* table_count);
  /* Initialize POSITION objects */
  for (i=0 ; i <= table_count ; i++)
    (void) new ((char*) (join->positions + i)) POSITION;

  join->best_ref= stat_vector;

  stat_end=stat+table_count;
  found_const_table_map= all_table_map=0;
  const_count=0;

  for (s= stat, i= 0; (tables= ti++); s++, i++)
  {
    TABLE_LIST *embedding= tables->embedding;
    stat_vector[i]=s;
    s->keys.init();
    s->const_keys.init();
    s->checked_keys.init();
    s->needed_reg.init();
    table_vector[i]=s->table=table=tables->table;
    s->tab_list= tables;
    table->pos_in_table_list= tables;
    error= tables->fetch_number_of_rows();
    set_statistics_for_table(join->thd, table);
    bitmap_clear_all(&table->cond_set);

#ifdef WITH_PARTITION_STORAGE_ENGINE
    const bool all_partitions_pruned_away= table->all_partitions_pruned_away;
#else
    const bool all_partitions_pruned_away= FALSE;
#endif

    DBUG_EXECUTE_IF("bug11747970_raise_error",
                    { join->thd->set_killed(KILL_QUERY_HARD); });
    if (unlikely(error))
    {
      table->file->print_error(error, MYF(0));
      goto error;
    }
    table->quick_keys.clear_all();
    table->intersect_keys.clear_all();
    table->reginfo.join_tab=s;
    table->reginfo.not_exists_optimize=0;
    bzero((char*) table->const_key_parts, sizeof(key_part_map)*table->s->keys);
    all_table_map|= table->map;
    s->preread_init_done= FALSE;
    s->join=join;

    s->dependent= tables->dep_tables;
    if (tables->schema_table)
      table->file->stats.records= table->used_stat_records= 2;
    table->quick_condition_rows= table->stat_records();

    s->on_expr_ref= &tables->on_expr;
    if (*s->on_expr_ref)
    {
      /* s is the only inner table of an outer join */
      if (!table->is_filled_at_execution() &&
          ((!table->file->stats.records &&
            (table->file->ha_table_flags() & HA_STATS_RECORDS_IS_EXACT)) ||
           all_partitions_pruned_away) && !embedding)
      {						// Empty table
        s->dependent= 0;                        // Ignore LEFT JOIN depend.
        no_rows_const_tables |= table->map;
	set_position(join,const_count++,s,(KEYUSE*) 0);
	continue;
      }
      outer_join|= table->map;
      s->embedding_map= 0;
      for (;embedding; embedding= embedding->embedding)
        s->embedding_map|= embedding->nested_join->nj_map;
      continue;
    }
    if (embedding)
    {
      /* s belongs to a nested join, maybe to several embedded joins */
      s->embedding_map= 0;
      bool inside_an_outer_join= FALSE;
      do
      {
        /* 
          If this is a semi-join nest, skip it, and proceed upwards. Maybe
          we're in some outer join nest
        */
        if (embedding->sj_on_expr)
        {
          embedding= embedding->embedding;
          continue;
        }
        inside_an_outer_join= TRUE;
        NESTED_JOIN *nested_join= embedding->nested_join;
        s->embedding_map|=nested_join->nj_map;
        s->dependent|= embedding->dep_tables;
        embedding= embedding->embedding;
        outer_join|= nested_join->used_tables;
      }
      while (embedding);
      if (inside_an_outer_join)
        continue;
    }
    if (!table->is_filled_at_execution() &&
        (table->s->system ||
         (table->file->stats.records <= 1 &&
          (table->file->ha_table_flags() & HA_STATS_RECORDS_IS_EXACT)) ||
         all_partitions_pruned_away) &&
	!s->dependent &&
        !table->fulltext_searched && !join->no_const_tables)
    {
      set_position(join,const_count++,s,(KEYUSE*) 0);
      no_rows_const_tables |= table->map;
    }
    
    /* SJ-Materialization handling: */
    if (table->pos_in_table_list->jtbm_subselect &&
        table->pos_in_table_list->jtbm_subselect->is_jtbm_const_tab)
    {
      set_position(join,const_count++,s,(KEYUSE*) 0);
      no_rows_const_tables |= table->map;
    }
  }

  stat_vector[i]=0;
  join->outer_join=outer_join;

  if (join->outer_join)
  {
    /* 
       Build transitive closure for relation 'to be dependent on'.
       This will speed up the plan search for many cases with outer joins,
       as well as allow us to catch illegal cross references/
       Warshall's algorithm is used to build the transitive closure.
       As we use bitmaps to represent the relation the complexity
       of the algorithm is O((number of tables)^2).

       The classic form of the Warshall's algorithm would look like: 
       for (i= 0; i < table_count; i++)
       {
         for (j= 0; j < table_count; j++)
         {
           for (k= 0; k < table_count; k++)
           {
             if (bitmap_is_set(stat[j].dependent, i) &&
                 bitmap_is_set(stat[i].dependent, k))
               bitmap_set_bit(stat[j].dependent, k);
           }
         }
       }  
    */
    
    for (s= stat ; s < stat_end ; s++)
    {
      table= s->table;
      for (JOIN_TAB *t= stat ; t < stat_end ; t++)
      {
        if (t->dependent & table->map)
          t->dependent |= table->reginfo.join_tab->dependent;
      }
      if (outer_join & s->table->map)
        s->table->maybe_null= 1;
    }
    /* Catch illegal cross references for outer joins */
    for (i= 0, s= stat ; i < table_count ; i++, s++)
    {
      if (s->dependent & s->table->map)
      {
        join->table_count=0;			// Don't use join->table
        my_message(ER_WRONG_OUTER_JOIN,
                   ER_THD(join->thd, ER_WRONG_OUTER_JOIN), MYF(0));
        goto error;
      }
      s->key_dependent= s->dependent;
    }
  }

  if (join->conds || outer_join)
  {
    if (update_ref_and_keys(join->thd, keyuse_array, stat, join->table_count,
                            join->conds, ~outer_join, join->select_lex, &sargables))
      goto error;
    /*
      Keyparts without prefixes may be useful if this JOIN is a subquery, and
      if the subquery may be executed via the IN-EXISTS strategy.
    */
    bool skip_unprefixed_keyparts=
      !(join->is_in_subquery() &&
        ((Item_in_subselect*)join->unit->item)->test_strategy(SUBS_IN_TO_EXISTS));

    if (keyuse_array->elements &&
        sort_and_filter_keyuse(join->thd, keyuse_array,
                               skip_unprefixed_keyparts))
      goto error;
    DBUG_EXECUTE("opt", print_keyuse_array(keyuse_array););
  }

  join->const_table_map= no_rows_const_tables;
  join->const_tables= const_count;
  eliminate_tables(join);
  join->const_table_map &= ~no_rows_const_tables;
  const_count= join->const_tables;
  found_const_table_map= join->const_table_map;

  /* Read tables with 0 or 1 rows (system tables) */
  for (POSITION *p_pos=join->positions, *p_end=p_pos+const_count;
       p_pos < p_end ;
       p_pos++)
  {
    s= p_pos->table;
    if (! (s->table->map & join->eliminated_tables))
    {
      int tmp;
      s->type=JT_SYSTEM;
      join->const_table_map|=s->table->map;
      if ((tmp=join_read_const_table(join->thd, s, p_pos)))
      {
        if (tmp > 0)
          goto error;		// Fatal error
      }
      else
      {
        found_const_table_map|= s->table->map;
        s->table->pos_in_table_list->optimized_away= TRUE;
      }
    }
  }

  /* loop until no more const tables are found */
  int ref_changed;
  do
  {
    ref_changed = 0;
  more_const_tables_found:

    /*
      We only have to loop from stat_vector + const_count as
      set_position() will move all const_tables first in stat_vector
    */

    for (JOIN_TAB **pos=stat_vector+const_count ; (s= *pos) ; pos++)
    {
      table=s->table;

      if (table->is_filled_at_execution())
        continue;

      /* 
        If equi-join condition by a key is null rejecting and after a
        substitution of a const table the key value happens to be null
        then we can state that there are no matches for this equi-join.
      */  
      if ((keyuse= s->keyuse) && *s->on_expr_ref && !s->embedding_map &&
         !(table->map & join->eliminated_tables))
      {
        /* 
          When performing an outer join operation if there are no matching rows
          for the single row of the outer table all the inner tables are to be
          null complemented and thus considered as constant tables.
          Here we apply this consideration to the case of outer join operations 
          with a single inner table only because the case with nested tables
          would require a more thorough analysis.
          TODO. Apply single row substitution to null complemented inner tables
          for nested outer join operations. 
	*/              
        while (keyuse->table == table)
        {
          if (!keyuse->is_for_hash_join() && 
              !(keyuse->val->used_tables() & ~join->const_table_map) &&
              keyuse->val->is_null() && keyuse->null_rejecting)
          {
            s->type= JT_CONST;
            s->table->const_table= 1;
            mark_as_null_row(table);
            found_const_table_map|= table->map;
	    join->const_table_map|= table->map;
	    set_position(join,const_count++,s,(KEYUSE*) 0);
            goto more_const_tables_found;
           }
	  keyuse++;
        }
      }

      if (s->dependent)				// If dependent on some table
      {
	// All dep. must be constants
	if (s->dependent & ~(found_const_table_map))
	  continue;
	if (table->file->stats.records <= 1L &&
	    (table->file->ha_table_flags() & HA_STATS_RECORDS_IS_EXACT) &&
            !table->pos_in_table_list->embedding &&
	      !((outer_join & table->map) && 
		(*s->on_expr_ref)->is_expensive()))
	{					// system table
	  int tmp= 0;
	  s->type=JT_SYSTEM;
	  join->const_table_map|=table->map;
	  set_position(join,const_count++,s,(KEYUSE*) 0);
	  if ((tmp= join_read_const_table(join->thd, s, join->positions+const_count-1)))
	  {
	    if (tmp > 0)
	      goto error;			// Fatal error
	  }
	  else
	    found_const_table_map|= table->map;
	  continue;
	}
      }
      /* check if table can be read by key or table only uses const refs */
      if ((keyuse=s->keyuse))
      {
	s->type= JT_REF;
	while (keyuse->table == table)
	{
          if (keyuse->is_for_hash_join())
	  {
            keyuse++;
            continue;
          }
	  start_keyuse=keyuse;
	  key=keyuse->key;
	  s->keys.set_bit(key);               // TODO: remove this ?

          const_ref.clear_all();
	  eq_part.clear_all();
          has_expensive_keyparts= false;
	  do
	  {
            if (keyuse->val->type() != Item::NULL_ITEM &&
                !keyuse->optimize &&
                keyuse->keypart != FT_KEYPART)
	    {
	      if (!((~found_const_table_map) & keyuse->used_tables))
              {
		const_ref.set_bit(keyuse->keypart);
                if (keyuse->val->is_expensive())
                  has_expensive_keyparts= true;
              }
	      eq_part.set_bit(keyuse->keypart);
	    }
	    keyuse++;
	  } while (keyuse->table == table && keyuse->key == key);

          TABLE_LIST *embedding= table->pos_in_table_list->embedding;
          /*
            TODO (low priority): currently we ignore the const tables that
            are within a semi-join nest which is within an outer join nest.
            The effect of this is that we don't do const substitution for
            such tables.
          */
          KEY *keyinfo= table->key_info + key;
          uint  key_parts= table->actual_n_key_parts(keyinfo);
          if (eq_part.is_prefix(key_parts) &&
              !table->fulltext_searched && 
              (!embedding || (embedding->sj_on_expr && !embedding->embedding)))
	  {
            key_map base_part, base_const_ref, base_eq_part;
            base_part.set_prefix(keyinfo->user_defined_key_parts); 
            base_const_ref= const_ref;
            base_const_ref.intersect(base_part);
            base_eq_part= eq_part;
            base_eq_part.intersect(base_part);
            if (table->actual_key_flags(keyinfo) & HA_NOSAME)
            {
              
	      if (base_const_ref == base_eq_part &&
                  !has_expensive_keyparts &&
                  !((outer_join & table->map) &&
                    (*s->on_expr_ref)->is_expensive()))
	      {					// Found everything for ref.
	        int tmp;
	        ref_changed = 1;
	        s->type= JT_CONST;
	        join->const_table_map|=table->map;
	        set_position(join,const_count++,s,start_keyuse);
                /* create_ref_for_key will set s->table->const_table */
	        if (create_ref_for_key(join, s, start_keyuse, FALSE,
				       found_const_table_map))
                  goto error;
	        if ((tmp=join_read_const_table(join->thd, s,
                                               join->positions+const_count-1)))
	        {
		  if (tmp > 0)
		    goto error;			// Fatal error
	        }
	        else
		  found_const_table_map|= table->map;
	        break;
	      }
	    }
            else if (base_const_ref == base_eq_part)
              s->const_keys.set_bit(key);
          }
	}
      }
    }
  } while (ref_changed);
 
  join->sort_by_table= get_sort_by_table(join->order, join->group_list,
                                         join->select_lex->leaf_tables,
                                         join->const_table_map);
  /* 
    Update info on indexes that can be used for search lookups as
    reading const tables may has added new sargable predicates. 
  */
  if (const_count && sargables)
  {
    for( ; sargables->field ; sargables++)
    {
      Field *field= sargables->field;
      JOIN_TAB *join_tab= field->table->reginfo.join_tab;
      key_map possible_keys= field->key_start;
      possible_keys.intersect(field->table->keys_in_use_for_query);
      bool is_const= 1;
      for (uint j=0; j < sargables->num_values; j++)
        is_const&= sargables->arg_value[j]->const_item();
      if (is_const)
        join_tab[0].const_keys.merge(possible_keys);
    }
  }

  join->impossible_where= false;
  if (join->conds && const_count)
  {
    Item* &conds= join->conds;
    COND_EQUAL *orig_cond_equal = join->cond_equal;

    conds->update_used_tables();
    conds= conds->remove_eq_conds(join->thd, &join->cond_value, true);
    if (conds && conds->type() == Item::COND_ITEM &&
        ((Item_cond*) conds)->functype() == Item_func::COND_AND_FUNC)
      join->cond_equal= &((Item_cond_and*) conds)->m_cond_equal;
    join->select_lex->where= conds;
    if (join->cond_value == Item::COND_FALSE)
    {
      join->impossible_where= true;
      conds= new (join->thd->mem_root) Item_int(join->thd, (longlong) 0, 1);
    }

    join->cond_equal= NULL;
    if (conds) 
    { 
      if (conds->type() == Item::COND_ITEM && 
	  ((Item_cond*) conds)->functype() == Item_func::COND_AND_FUNC)
        join->cond_equal= (&((Item_cond_and *) conds)->m_cond_equal);
      else if (conds->type() == Item::FUNC_ITEM &&
	       ((Item_func*) conds)->functype() == Item_func::MULT_EQUAL_FUNC)
      {
        if (!join->cond_equal)
          join->cond_equal= new COND_EQUAL;
        join->cond_equal->current_level.empty();
        join->cond_equal->current_level.push_back((Item_equal*) conds,
                                                  join->thd->mem_root);
      }
    }

    if (orig_cond_equal != join->cond_equal)
    {
      /*
        If join->cond_equal has changed all references to it from COND_EQUAL
        objects associated with ON expressions must be updated.
      */
      for (JOIN_TAB **pos=stat_vector+const_count ; (s= *pos) ; pos++) 
      {
        if (*s->on_expr_ref && s->cond_equal &&
	    s->cond_equal->upper_levels == orig_cond_equal)
          s->cond_equal->upper_levels= join->cond_equal;
      }
    }
  }

  /* Calc how many (possible) matched records in each table */

  for (s=stat ; s < stat_end ; s++)
  {
    s->startup_cost= 0;
    if (s->type == JT_SYSTEM || s->type == JT_CONST)
    {
      /* Only one matching row */
      s->found_records= s->records= 1;
      s->read_time=1.0; 
      s->worst_seeks=1.0;
      continue;
    }
    /* Approximate found rows and time to read them */
    if (s->table->is_filled_at_execution())
    {
      get_delayed_table_estimates(s->table, &s->records, &s->read_time,
                                  &s->startup_cost);
      s->found_records= s->records;
      table->quick_condition_rows=s->records;
    }
    else
    {
       s->scan_time();
    }

    if (s->table->is_splittable())
      s->add_keyuses_for_splitting();

    /*
      Set a max range of how many seeks we can expect when using keys
      This is can't be to high as otherwise we are likely to use
      table scan.
    */
    s->worst_seeks= MY_MIN((double) s->found_records / 10,
			(double) s->read_time*3);
    if (s->worst_seeks < 2.0)			// Fix for small tables
      s->worst_seeks=2.0;

    /*
      Add to stat->const_keys those indexes for which all group fields or
      all select distinct fields participate in one index.
    */
    add_group_and_distinct_keys(join, s);

    s->table->cond_selectivity= 1.0;
    
    /*
      Perform range analysis if there are keys it could use (1). 
      Don't do range analysis for materialized subqueries (2).
      Don't do range analysis for materialized derived tables (3)
    */
    if ((!s->const_keys.is_clear_all() ||
	 !bitmap_is_clear_all(&s->table->cond_set)) &&              // (1)
        !s->table->is_filled_at_execution() &&                      // (2)
        !(s->table->pos_in_table_list->derived &&                   // (3)
          s->table->pos_in_table_list->is_materialized_derived()))  // (3)
    {
      bool impossible_range= FALSE;
      ha_rows records= HA_POS_ERROR;
      SQL_SELECT *select= 0;
      Item **sargable_cond= NULL;
      if (!s->const_keys.is_clear_all())
      {
        sargable_cond= get_sargable_cond(join, s->table);

        select= make_select(s->table, found_const_table_map,
			    found_const_table_map,
                            *sargable_cond,
                            (SORT_INFO*) 0,
			    1, &error);
        if (!select)
          goto error;
        records= get_quick_record_count(join->thd, select, s->table,
				        &s->const_keys, join->row_limit);

        /*
          Range analyzer might have modified the condition. Put it the new
          condition to where we got it from.
        */
        *sargable_cond= select->cond;

        s->quick=select->quick;
        s->needed_reg=select->needed_reg;
        select->quick=0;
        impossible_range= records == 0 && s->table->reginfo.impossible_range;
      }
      if (!impossible_range)
      {
        if (!sargable_cond)
          sargable_cond= get_sargable_cond(join, s->table);
        if (join->thd->variables.optimizer_use_condition_selectivity > 1)
          calculate_cond_selectivity_for_table(join->thd, s->table, 
                                               sargable_cond);
        if (s->table->reginfo.impossible_range)
	{
          impossible_range= TRUE;
          records= 0;
        }
      }
      if (impossible_range)
      {
        /*
          Impossible WHERE or ON expression
          In case of ON, we mark that the we match one empty NULL row.
          In case of WHERE, don't set found_const_table_map to get the
          caller to abort with a zero row result.
        */
        TABLE_LIST *emb= s->table->pos_in_table_list->embedding;
        if (emb && !emb->sj_on_expr)
        {
          /* Mark all tables in a multi-table join nest as const */
          mark_join_nest_as_const(join, emb, &found_const_table_map,
                                &const_count);
        }
        else
        {
          join->const_table_map|= s->table->map;
          set_position(join,const_count++,s,(KEYUSE*) 0);
          s->type= JT_CONST;
          s->table->const_table= 1;
          if (*s->on_expr_ref)
          {
            /* Generate empty row */
            s->info= ET_IMPOSSIBLE_ON_CONDITION;
            found_const_table_map|= s->table->map;
            mark_as_null_row(s->table);		// All fields are NULL
          }
        }
      }
      if (records != HA_POS_ERROR)
      {
	s->found_records=records;
	s->read_time= s->quick ? s->quick->read_time : 0.0;
      }
      if (select)
        delete select;
    }

  }

  if (pull_out_semijoin_tables(join))
    DBUG_RETURN(TRUE);

  join->join_tab=stat;
  join->top_join_tab_count= table_count;
  join->map2table=stat_ref;
  join->table= table_vector;
  join->const_tables=const_count;
  join->found_const_table_map=found_const_table_map;

  if (join->const_tables != join->table_count)
    optimize_keyuse(join, keyuse_array);
   
  DBUG_ASSERT(!join->conds || !join->cond_equal ||
              !join->cond_equal->current_level.elements ||
              (join->conds->type() == Item::COND_ITEM &&
	       ((Item_cond*) (join->conds))->functype() ==
               Item_func::COND_AND_FUNC && 
               join->cond_equal ==
	       &((Item_cond_and *) (join->conds))->m_cond_equal) ||
              (join->conds->type() == Item::FUNC_ITEM &&
	       ((Item_func*) (join->conds))->functype() ==
               Item_func::MULT_EQUAL_FUNC &&
	       join->cond_equal->current_level.elements == 1 &&
               join->cond_equal->current_level.head() == join->conds));

  if (optimize_semijoin_nests(join, all_table_map))
    DBUG_RETURN(TRUE); /* purecov: inspected */

  {
    double records= 1;
    SELECT_LEX_UNIT *unit= join->select_lex->master_unit();

    /* Find an optimal join order of the non-constant tables. */
    if (join->const_tables != join->table_count)
    {
      if (choose_plan(join, all_table_map & ~join->const_table_map))
        goto error;

#ifdef HAVE_valgrind
      // JOIN::positions holds the current query plan. We've already
      // made the plan choice, so we should only use JOIN::best_positions
      for (uint k=join->const_tables; k < join->table_count; k++)
        MEM_UNDEFINED(&join->positions[k], sizeof(join->positions[k]));
#endif
    }
    else
    {
      memcpy((uchar*) join->best_positions,(uchar*) join->positions,
	     sizeof(POSITION)*join->const_tables);
      join->join_record_count= 1.0;
      join->best_read=1.0;
    }
  
    if (!(join->select_options & SELECT_DESCRIBE) &&
        unit->derived && unit->derived->is_materialized_derived())
    {
      /*
        Calculate estimated number of rows for materialized derived
        table/view.
      */
      for (i= 0; i < join->table_count ; i++)
        if (double rr= join->best_positions[i].records_read)
          records= COST_MULT(records, rr);
      ha_rows rows= records > (double) HA_ROWS_MAX ? HA_ROWS_MAX : (ha_rows) records;
      set_if_smaller(rows, unit->select_limit_cnt);
      join->select_lex->increase_derived_records(rows);
    }
  }

  if (join->choose_subquery_plan(all_table_map & ~join->const_table_map))
    goto error;

  DEBUG_SYNC(join->thd, "inside_make_join_statistics");

  DBUG_RETURN(0);

error:
  /*
    Need to clean up join_tab from TABLEs in case of error.
    They won't get cleaned up by JOIN::cleanup() because JOIN::join_tab
    may not be assigned yet by this function (which is building join_tab).
    Dangling TABLE::reginfo.join_tab may cause part_of_refkey to choke. 
  */
  {    
    TABLE_LIST *tmp_table;
    List_iterator<TABLE_LIST> ti2(tables_list);
    while ((tmp_table= ti2++))
      tmp_table->table->reginfo.join_tab= NULL;
  }
  DBUG_RETURN (1);
}

Project: server

static ha_rows get_quick_record_count(THD *thd, SQL_SELECT *select,
				      TABLE *table,
				      const key_map *keys,ha_rows limit)
{
  int error;
  DBUG_ENTER("get_quick_record_count");
  uchar buff[STACK_BUFF_ALLOC];
  if (unlikely(check_stack_overrun(thd, STACK_MIN_SIZE, buff)))
    DBUG_RETURN(0);                           // Fatal error flag is set
  if (select)
  {
    select->head=table;
    table->reginfo.impossible_range=0;
    if (likely((error=
                select->test_quick_select(thd, *(key_map *)keys,
                                          (table_map) 0,
                                          limit, 0, FALSE,
                                          TRUE /* remove_where_parts*/)) ==
               1))
      DBUG_RETURN(select->quick->records);
    if (unlikely(error == -1))
    {
      table->reginfo.impossible_range=1;
      DBUG_RETURN(0);
    }
    DBUG_PRINT("warning",("Couldn't use record count on const keypart"));
  }
  DBUG_RETURN(HA_POS_ERROR);			/* This shouldn't happend */
}