find_order_in_list(THD *thd, Ref_ptr_array ref_pointer_array,
                   TABLE_LIST *tables,
                   ORDER *order, List<Item> &fields, List<Item> &all_fields,
                   bool is_group_field, bool add_to_all_fields,
                   bool from_window_spec)
{
  Item *order_item= *order->item; /* The item from the GROUP/ORDER caluse. */
  Item::Type order_item_type;
  Item **select_item; /* The corresponding item from the SELECT clause. */
  Field *from_field;  /* The corresponding field from the FROM clause. */
  uint counter;
  enum_resolution_type resolution;

  /*
    Local SP variables may be int but are expressions, not positions.
    (And they can't be used before fix_fields is called for them).
  */
  if (order_item->type() == Item::INT_ITEM && order_item->basic_const_item() &&
      !from_window_spec)
  {						/* Order by position */
    uint count;
    if (order->counter_used)
      count= order->counter; // counter was once resolved
    else
      count= (uint) order_item->val_int();
    if (!count || count > fields.elements)
    {
      my_error(ER_BAD_FIELD_ERROR, MYF(0),
               order_item->full_name(), thd->where);
      return TRUE;
    }
    thd->change_item_tree((Item **)&order->item, (Item *)&ref_pointer_array[count - 1]);
    order->in_field_list= 1;
    order->counter= count;
    order->counter_used= 1;
    return FALSE;
  }
  /* Lookup the current GROUP/ORDER field in the SELECT clause. */
  select_item= find_item_in_list(order_item, fields, &counter,
                                 REPORT_EXCEPT_NOT_FOUND, &resolution);
  if (!select_item)
    return TRUE; /* The item is not unique, or some other error occurred. */

  /* Check whether the resolved field is not ambiguos. */
  if (select_item != not_found_item)
  {
    Item *view_ref= NULL;
    /*
      If we have found field not by its alias in select list but by its
      original field name, we should additionally check if we have conflict
      for this name (in case if we would perform lookup in all tables).
    */
    if (resolution == RESOLVED_BEHIND_ALIAS && !order_item->fixed &&
        order_item->fix_fields(thd, order->item))
      return TRUE;

    /* Lookup the current GROUP field in the FROM clause. */
    order_item_type= order_item->type();
    from_field= (Field*) not_found_field;
    if ((is_group_field && order_item_type == Item::FIELD_ITEM) ||
        order_item_type == Item::REF_ITEM)
    {
      from_field= find_field_in_tables(thd, (Item_ident*) order_item, tables,
                                       NULL, &view_ref, IGNORE_ERRORS, FALSE,
                                       FALSE);
      if (!from_field)
        from_field= (Field*) not_found_field;
    }

    if (from_field == not_found_field ||
        (from_field != view_ref_found ?
         /* it is field of base table => check that fields are same */
         ((*select_item)->type() == Item::FIELD_ITEM &&
          ((Item_field*) (*select_item))->field->eq(from_field)) :
         /*
           in is field of view table => check that references on translation
           table are same
         */
         ((*select_item)->type() == Item::REF_ITEM &&
          view_ref->type() == Item::REF_ITEM &&
          ((Item_ref *) (*select_item))->ref ==
          ((Item_ref *) view_ref)->ref)))
    {
      /*
        If there is no such field in the FROM clause, or it is the same field
        as the one found in the SELECT clause, then use the Item created for
        the SELECT field. As a result if there was a derived field that
        'shadowed' a table field with the same name, the table field will be
        chosen over the derived field.
      */
      order->item= &ref_pointer_array[counter];
      order->in_field_list=1;
      return FALSE;
    }
    else
    {
      /*
        There is a field with the same name in the FROM clause. This
        is the field that will be chosen. In this case we issue a
        warning so the user knows that the field from the FROM clause
        overshadows the column reference from the SELECT list.
      */
      push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
                          ER_NON_UNIQ_ERROR,
                          ER_THD(thd, ER_NON_UNIQ_ERROR),
                          ((Item_ident*) order_item)->field_name,
                          thd->where);
    }
  }
  else if (from_window_spec)
  {
    Item **found_item= find_item_in_list(order_item, all_fields, &counter,
                                         REPORT_EXCEPT_NOT_FOUND, &resolution,
                                         all_fields.elements - fields.elements);
    if (found_item != not_found_item)
    {
      order->item= &ref_pointer_array[all_fields.elements-1-counter];
      order->in_field_list= 0;
      return FALSE;
    }
  }

  order->in_field_list=0;
  /*
    The call to order_item->fix_fields() means that here we resolve
    'order_item' to a column from a table in the list 'tables', or to
    a column in some outer query. Exactly because of the second case
    we come to this point even if (select_item == not_found_item),
    inspite of that fix_fields() calls find_item_in_list() one more
    time.

    We check order_item->fixed because Item_func_group_concat can put
    arguments for which fix_fields already was called.
  */
  if (!order_item->fixed &&
      (order_item->fix_fields(thd, order->item) ||
       (order_item= *order->item)->check_cols(1) ||
       thd->is_error()))
    return TRUE; /* Wrong field. */

  if (!add_to_all_fields)
    return FALSE;

  uint el= all_fields.elements;
 /* Add new field to field list. */
  all_fields.push_front(order_item, thd->mem_root);
  ref_pointer_array[el]= order_item;
  /*
     If the order_item is a SUM_FUNC_ITEM, when fix_fields is called
     ref_by is set to order->item which is the address of order_item.
     But this needs to be address of order_item in the all_fields list.
     As a result, when it gets replaced with Item_aggregate_ref
     object in Item::split_sum_func2, we will be able to retrieve the
     newly created object.
  */
  if (order_item->type() == Item::SUM_FUNC_ITEM)
    ((Item_sum *)order_item)->ref_by= all_fields.head_ref();

  order->item= &ref_pointer_array[el];
  return FALSE;
}


bool JOIN::make_aggr_tables_info()
{
  List<Item> *curr_all_fields= &all_fields;
  List<Item> *curr_fields_list= &fields_list;
  JOIN_TAB *curr_tab= join_tab + const_tables;
  TABLE *exec_tmp_table= NULL;
  bool distinct= false;
  bool keep_row_order= false;
  bool is_having_added_as_table_cond= false;
  DBUG_ENTER("JOIN::make_aggr_tables_info");

  const bool has_group_by= this->group;

  sort_and_group_aggr_tab= NULL;

  if (group_optimized_away)
    implicit_grouping= true;

  bool implicit_grouping_with_window_funcs= implicit_grouping &&
                                            select_lex->have_window_funcs();
  bool implicit_grouping_without_tables= implicit_grouping &&
                                         !tables_list;

  /*
    Setup last table to provide fields and all_fields lists to the next
    node in the plan.
  */
  if (join_tab && top_join_tab_count && tables_list)
  {
    join_tab[top_join_tab_count - 1].fields= &fields_list;
    join_tab[top_join_tab_count - 1].all_fields= &all_fields;
  }

  /*
    All optimization is done. Check if we can use the storage engines
    group by handler to evaluate the group by
  */
  if (tables_list && (tmp_table_param.sum_func_count || group_list) &&
      !procedure)
  {
    /*
      At the moment we only support push down for queries where
      all tables are in the same storage engine
    */
    TABLE_LIST *tbl= tables_list;
    handlerton *ht= tbl && tbl->table ? tbl->table->file->ht : 0;
    for (tbl= tbl->next_local; ht && tbl; tbl= tbl->next_local)
    {
      if (!tbl->table || tbl->table->file->ht != ht)
        ht= 0;
    }

    if (ht && ht->create_group_by)
    {
      /* Check if the storage engine can intercept the query */
      Query query= {&all_fields, select_distinct, tables_list, conds,
                    group_list, order ? order : group_list, having};
      group_by_handler *gbh= ht->create_group_by(thd, &query);

      if (gbh)
      {
        pushdown_query= new (thd->mem_root) Pushdown_query(select_lex, gbh);
        /*
          We must store rows in the tmp table if we need to do an ORDER BY
          or DISTINCT and the storage handler can't handle it.
        */
        need_tmp= query.order_by || query.group_by || query.distinct;
        distinct= query.distinct;
        keep_row_order= query.order_by || query.group_by;

        order= query.order_by;

        aggr_tables++;
        curr_tab= join_tab + exec_join_tab_cnt();
        bzero((void*)curr_tab, sizeof(JOIN_TAB));
        curr_tab->ref.key= -1;
        curr_tab->join= this;

        curr_tab->tmp_table_param= new TMP_TABLE_PARAM(tmp_table_param);
        TABLE* table= create_tmp_table(thd, curr_tab->tmp_table_param,
                                       all_fields,
                                       NULL, query.distinct,
                                       TRUE, select_options, HA_POS_ERROR,
                                       "", !need_tmp,
                                       query.order_by || query.group_by);
        if (!table)
          DBUG_RETURN(1);

        curr_tab->aggr= new (thd->mem_root) AGGR_OP(curr_tab);
        curr_tab->aggr->set_write_func(::end_send);
        curr_tab->table= table;
        /*
          Setup reference fields, used by summary functions and group by fields,
          to point to the temporary table.
          The actual switching to the temporary tables fields for HAVING
          and ORDER BY is done in do_select() by calling
          set_items_ref_array(items1).
        */
        init_items_ref_array();
        items1= ref_ptr_array_slice(2);
        //items1= items0 + all_fields.elements;
        if (change_to_use_tmp_fields(thd, items1,
                                     tmp_fields_list1, tmp_all_fields1,
                                     fields_list.elements, all_fields))
          DBUG_RETURN(1);

        /* Give storage engine access to temporary table */
        gbh->table= table;
        pushdown_query->store_data_in_temp_table= need_tmp;
        pushdown_query->having= having;

        /*
          Group by and having is calculated by the group_by handler.
          Reset the group by and having
        */
        DBUG_ASSERT(query.group_by == NULL);
        group= 0; group_list= 0;
        having= tmp_having= 0;
        /*
          Select distinct is handled by handler or by creating an unique index
          over all fields in the temporary table
        */
        select_distinct= 0;
        order= query.order_by;
        tmp_table_param.field_count+= tmp_table_param.sum_func_count;
        tmp_table_param.sum_func_count= 0;

        fields= curr_fields_list;

        //todo: new:
        curr_tab->ref_array= &items1;
        curr_tab->all_fields= &tmp_all_fields1;
        curr_tab->fields= &tmp_fields_list1;

        DBUG_RETURN(thd->is_fatal_error);
      }
    }
  }

  /*
    The loose index scan access method guarantees that all grouping or
    duplicate row elimination (for distinct) is already performed
    during data retrieval, and that all MIN/MAX functions are already
    computed for each group. Thus all MIN/MAX functions should be
    treated as regular functions, and there is no need to perform
    grouping in the main execution loop.
    Notice that currently loose index scan is applicable only for
    single table queries, thus it is sufficient to test only the first
    join_tab element of the plan for its access method.
  */
  if (join_tab && top_join_tab_count && tables_list &&
      join_tab->is_using_loose_index_scan())
    tmp_table_param.precomputed_group_by=
      !join_tab->is_using_agg_loose_index_scan();

  group_list_for_estimates= group_list;
  /* Create a tmp table if distinct or if the sort is too complicated */
  if (need_tmp)
  {
    aggr_tables++;
    curr_tab= join_tab + exec_join_tab_cnt();
    bzero((void*)curr_tab, sizeof(JOIN_TAB));
    curr_tab->ref.key= -1;
    if (only_const_tables())
      first_select= sub_select_postjoin_aggr;

    /*
      Create temporary table on first execution of this join.
      (Will be reused if this is a subquery that is executed several times.)
    */
    init_items_ref_array();

    ORDER *tmp_group= (ORDER *) 0;
    if (!simple_group && !procedure && !(test_flags & TEST_NO_KEY_GROUP))
      tmp_group= group_list;

    tmp_table_param.hidden_field_count=
      all_fields.elements - fields_list.elements;

    distinct= select_distinct && !group_list &&
              !select_lex->have_window_funcs();
    keep_row_order= false;
    bool save_sum_fields= (group_list && simple_group) ||
                           implicit_grouping_with_window_funcs;
    if (create_postjoin_aggr_table(curr_tab,
                                   &all_fields, tmp_group,
                                   save_sum_fields,
                                   distinct, keep_row_order))
      DBUG_RETURN(true);
    exec_tmp_table= curr_tab->table;

    if (exec_tmp_table->distinct)
      optimize_distinct();

   /* Change sum_fields reference to calculated fields in tmp_table */
    items1= ref_ptr_array_slice(2);
    if ((sort_and_group || curr_tab->table->group ||
         tmp_table_param.precomputed_group_by) &&
         !implicit_grouping_without_tables)
    {
      if (change_to_use_tmp_fields(thd, items1,
                                   tmp_fields_list1, tmp_all_fields1,
                                   fields_list.elements, all_fields))
        DBUG_RETURN(true);
    }
    else
    {
      if (change_refs_to_tmp_fields(thd, items1,
                                    tmp_fields_list1, tmp_all_fields1,
                                    fields_list.elements, all_fields))
        DBUG_RETURN(true);
    }
    curr_all_fields= &tmp_all_fields1;
    curr_fields_list= &tmp_fields_list1;
    // Need to set them now for correct group_fields setup, reset at the end.
    set_items_ref_array(items1);
    curr_tab->ref_array= &items1;
    curr_tab->all_fields= &tmp_all_fields1;
    curr_tab->fields= &tmp_fields_list1;
    set_postjoin_aggr_write_func(curr_tab);

    /*
      If having is not handled here, it will be checked before the row is sent
      to the client.
    */
    if (tmp_having &&
        (sort_and_group || (exec_tmp_table->distinct && !group_list) ||
	 select_lex->have_window_funcs()))
    {
      /*
        If there is no select distinct and there are no window functions
        then move the having to table conds of tmp table.
        NOTE : We cannot apply having after distinct or window functions
               If columns of having are not part of select distinct,
               then distinct may remove rows which can satisfy having.
               In the case of window functions we *must* make sure to not
               store any rows which don't match HAVING within the temp table,
               as rows will end up being used during their computation.
      */
      if (!select_distinct && !select_lex->have_window_funcs() &&
          add_having_as_table_cond(curr_tab))
        DBUG_RETURN(true);
      is_having_added_as_table_cond= tmp_having != having;

      /*
        Having condition which we are not able to add as tmp table conds are
        kept as before. And, this will be applied before storing the rows in
        tmp table.
      */
      curr_tab->having= having;
      having= NULL; // Already done
    }

    tmp_table_param.func_count= 0;
    tmp_table_param.field_count+= tmp_table_param.func_count;
    if (sort_and_group || curr_tab->table->group)
    {
      tmp_table_param.field_count+= tmp_table_param.sum_func_count;
      tmp_table_param.sum_func_count= 0;
    }

    if (exec_tmp_table->group)
    {						// Already grouped
      if (!order && !no_order && !skip_sort_order)
        order= group_list;  /* order by group */
      group_list= NULL;
    }

    /*
      If we have different sort & group then we must sort the data by group
      and copy it to another tmp table
      This code is also used if we are using distinct something
      we haven't been able to store in the temporary table yet
      like SEC_TO_TIME(SUM(...)).
    */
    if ((group_list &&
         (!test_if_subpart(group_list, order) || select_distinct)) ||
        (select_distinct && tmp_table_param.using_outer_summary_function))
    {					/* Must copy to another table */
      DBUG_PRINT("info",("Creating group table"));

      calc_group_buffer(this, group_list);
      count_field_types(select_lex, &tmp_table_param, tmp_all_fields1,
                        select_distinct && !group_list);
      tmp_table_param.hidden_field_count=
        tmp_all_fields1.elements - tmp_fields_list1.elements;

      curr_tab++;
      aggr_tables++;
      bzero((void*)curr_tab, sizeof(JOIN_TAB));
      curr_tab->ref.key= -1;

      /* group data to new table */
      /*
        If the access method is loose index scan then all MIN/MAX
        functions are precomputed, and should be treated as regular
        functions. See extended comment above.
      */
      if (join_tab->is_using_loose_index_scan())
        tmp_table_param.precomputed_group_by= TRUE;

      tmp_table_param.hidden_field_count=
        curr_all_fields->elements - curr_fields_list->elements;
      ORDER *dummy= NULL; //TODO can use table->group here also

      if (create_postjoin_aggr_table(curr_tab,
                                     curr_all_fields, dummy, true,
                                     distinct, keep_row_order))
	DBUG_RETURN(true);

      if (group_list)
      {
        if (!only_const_tables())        // No need to sort a single row
        {
          if (add_sorting_to_table(curr_tab - 1, group_list))
            DBUG_RETURN(true);
        }

        if (make_group_fields(this, this))
          DBUG_RETURN(true);
      }

      // Setup sum funcs only when necessary, otherwise we might break info
      // for the first table
      if (group_list || tmp_table_param.sum_func_count)
      {
        if (make_sum_func_list(*curr_all_fields, *curr_fields_list, true, true))
          DBUG_RETURN(true);
        if (prepare_sum_aggregators(sum_funcs,
                                    !join_tab->is_using_agg_loose_index_scan()))
          DBUG_RETURN(true);
        group_list= NULL;
        if (setup_sum_funcs(thd, sum_funcs))
          DBUG_RETURN(true);
      }
      // No sum funcs anymore
      DBUG_ASSERT(items2.is_null());

      items2= ref_ptr_array_slice(3);
      if (change_to_use_tmp_fields(thd, items2,
                                   tmp_fields_list2, tmp_all_fields2,
                                   fields_list.elements, tmp_all_fields1))
        DBUG_RETURN(true);

      curr_fields_list= &tmp_fields_list2;
      curr_all_fields= &tmp_all_fields2;
      set_items_ref_array(items2);
      curr_tab->ref_array= &items2;
      curr_tab->all_fields= &tmp_all_fields2;
      curr_tab->fields= &tmp_fields_list2;
      set_postjoin_aggr_write_func(curr_tab);

      tmp_table_param.field_count+= tmp_table_param.sum_func_count;
      tmp_table_param.sum_func_count= 0;
    }
    if (curr_tab->table->distinct)
      select_distinct= false;               /* Each row is unique */

    if (select_distinct && !group_list)
    {
      if (having)
      {
        curr_tab->having= having;
        having->update_used_tables();
      }
      /*
        We only need DISTINCT operation if the join is not degenerate.
        If it is, we must not request DISTINCT processing, because
        remove_duplicates() assumes there is a preceding computation step (and
        in the degenerate join, there's none)
      */
      if (top_join_tab_count && tables_list)
        curr_tab->distinct= true;

      having= NULL;
      select_distinct= false;
    }
    /* Clean tmp_table_param for the next tmp table. */
    tmp_table_param.field_count= tmp_table_param.sum_func_count=
      tmp_table_param.func_count= 0;

    tmp_table_param.copy_field= tmp_table_param.copy_field_end=0;
    first_record= sort_and_group=0;

    if (!group_optimized_away || implicit_grouping_with_window_funcs)
    {
      group= false;
    }
    else
    {
      /*
        If grouping has been optimized away, a temporary table is
        normally not needed unless we're explicitly requested to create
        one (e.g. due to a SQL_BUFFER_RESULT hint or INSERT ... SELECT).

        In this case (grouping was optimized away), temp_table was
        created without a grouping expression and JOIN::exec() will not
        perform the necessary grouping (by the use of end_send_group()
        or end_write_group()) if JOIN::group is set to false.
      */
      // the temporary table was explicitly requested
      DBUG_ASSERT(MY_TEST(select_options & OPTION_BUFFER_RESULT));
      // the temporary table does not have a grouping expression
      DBUG_ASSERT(!curr_tab->table->group);
    }
    calc_group_buffer(this, group_list);
    count_field_types(select_lex, &tmp_table_param, *curr_all_fields, false);
  }

  if (group ||
      (implicit_grouping  && !implicit_grouping_with_window_funcs) ||
      tmp_table_param.sum_func_count)
  {
    if (make_group_fields(this, this))
      DBUG_RETURN(true);

    DBUG_ASSERT(items3.is_null());

    if (items0.is_null())
      init_items_ref_array();
    items3= ref_ptr_array_slice(4);
    setup_copy_fields(thd, &tmp_table_param,
                      items3, tmp_fields_list3, tmp_all_fields3,
                      curr_fields_list->elements, *curr_all_fields);

    curr_fields_list= &tmp_fields_list3;
    curr_all_fields= &tmp_all_fields3;
    set_items_ref_array(items3);
    if (join_tab)
    {
      JOIN_TAB *last_tab= join_tab + top_join_tab_count + aggr_tables - 1;
      // Set grouped fields on the last table
      last_tab->ref_array= &items3;
      last_tab->all_fields= &tmp_all_fields3;
      last_tab->fields= &tmp_fields_list3;
    }
    if (make_sum_func_list(*curr_all_fields, *curr_fields_list, true, true))
      DBUG_RETURN(true);
    if (prepare_sum_aggregators(sum_funcs,
                                !join_tab ||
                                !join_tab-> is_using_agg_loose_index_scan()))
      DBUG_RETURN(true);
    if (setup_sum_funcs(thd, sum_funcs) || thd->is_fatal_error)
      DBUG_RETURN(true);
  }
  if (group_list || order)
  {
    DBUG_PRINT("info",("Sorting for send_result_set_metadata"));
    THD_STAGE_INFO(thd, stage_sorting_result);
    /* If we have already done the group, add HAVING to sorted table */
    if (tmp_having && !is_having_added_as_table_cond &&
        !group_list && !sort_and_group)
    {
      if (add_having_as_table_cond(curr_tab))
        DBUG_RETURN(true);
    }

    if (group)
      select_limit= HA_POS_ERROR;
    else if (!need_tmp)
    {
      /*
        We can abort sorting after thd->select_limit rows if there are no
        filter conditions for any tables after the sorted one.
        Filter conditions come in several forms:
         1. as a condition item attached to the join_tab, or
         2. as a keyuse attached to the join_tab (ref access).
      */
      for (uint i= const_tables + 1; i < top_join_tab_count; i++)
      {
        JOIN_TAB *const tab= join_tab + i;
        if (tab->select_cond ||                                // 1
            (tab->keyuse && !tab->first_inner))                // 2
        {
          /* We have to sort all rows */
          select_limit= HA_POS_ERROR;
          break;
        }
      }
    }
    /*
      Here we add sorting stage for ORDER BY/GROUP BY clause, if the
      optimiser chose FILESORT to be faster than INDEX SCAN or there is
      no suitable index present.
      OPTION_FOUND_ROWS supersedes LIMIT and is taken into account.
    */
    DBUG_PRINT("info",("Sorting for order by/group by"));
    ORDER *order_arg= group_list ?  group_list : order;
    if (top_join_tab_count + aggr_tables > const_tables &&
        ordered_index_usage !=
        (group_list ? ordered_index_group_by : ordered_index_order_by) &&
        curr_tab->type != JT_CONST &&
        curr_tab->type != JT_EQ_REF) // Don't sort 1 row
    {
      // Sort either first non-const table or the last tmp table
      JOIN_TAB *sort_tab= curr_tab;

      if (add_sorting_to_table(sort_tab, order_arg))
        DBUG_RETURN(true);
      /*
        filesort_limit:	 Return only this many rows from filesort().
        We can use select_limit_cnt only if we have no group_by and 1 table.
        This allows us to use Bounded_queue for queries like:
          "select SQL_CALC_FOUND_ROWS * from t1 order by b desc limit 1;"
        m_select_limit == HA_POS_ERROR (we need a full table scan)
        unit->select_limit_cnt == 1 (we only need one row in the result set)
      */
      sort_tab->filesort->limit=
        (has_group_by || (join_tab + table_count > curr_tab + 1)) ?
         select_limit : unit->select_limit_cnt;
    }
    if (!only_const_tables() &&
        !join_tab[const_tables].filesort &&
        !(select_options & SELECT_DESCRIBE))
    {
      /*
        If no IO cache exists for the first table then we are using an
        INDEX SCAN and no filesort. Thus we should not remove the sorted
        attribute on the INDEX SCAN.
      */
      skip_sort_order= true;
    }
  }

  /*
    Window functions computation step should be attached to the last join_tab
    that's doing aggregation.
    The last join_tab reads the data from the temp. table.  It also may do
    - sorting
    - duplicate value removal
    Both of these operations are done after window function computation step.
  */
  curr_tab= join_tab + total_join_tab_cnt();
  if (select_lex->window_funcs.elements)
  {
    curr_tab->window_funcs_step= new Window_funcs_computation;
    if (curr_tab->window_funcs_step->setup(thd, &select_lex->window_funcs,
                                           curr_tab))
      DBUG_RETURN(true);
    /* Count that we're using window functions. */
    status_var_increment(thd->status_var.feature_window_functions);
  }

  fields= curr_fields_list;
  // Reset before execution
  set_items_ref_array(items0);
  if (join_tab)
    join_tab[exec_join_tab_cnt() + aggr_tables - 1].next_select=
      setup_end_select_func(this, NULL);
  group= has_group_by;

  DBUG_RETURN(false);
}

MDEV-21028 Server crashes in Query_arena::set_query_arena upon SELECT from view

if the view has algorithm=temptable it is not updatable,
so DEFAULT() for its fields is meaningless,
and thus it's NULL or 0/'' for NOT NULL columns.


join_read_prev_same(READ_RECORD *info)
{
  int error;
  TABLE *table= info->table;
  JOIN_TAB *tab=table->reginfo.join_tab;

  if ((error= table->file->ha_index_prev(table->record[0])))
    return report_error(table, error);
  if (key_cmp_if_same(table, tab->ref.key_buff, tab->ref.key,
                      tab->ref.key_length))
  {
    table->status=STATUS_NOT_FOUND;
    error= -1;
  }
  return error;
}


static int remove_dup_with_compare(THD *thd, TABLE *table, Field **first_field,
				   Item *having)
{
  handler *file=table->file;
  uchar *record=table->record[0];
  int error;
  DBUG_ENTER("remove_dup_with_compare");

  if (file->ha_rnd_init_with_error(1))
    DBUG_RETURN(1);

  error= file->ha_rnd_next(record);
  for (;;)
  {
    if (thd->check_killed())
    {
      thd->send_kill_message();
      error=0;
      goto err;
    }
    if (error)
    {
      if (error == HA_ERR_RECORD_DELETED)
      {
        error= file->ha_rnd_next(record);
        continue;
      }
      if (error == HA_ERR_END_OF_FILE)
	break;
      goto err;
    }
    if (having && !having->val_int())
    {
      if ((error= file->ha_delete_row(record)))
	goto err;
      error= file->ha_rnd_next(record);
      continue;
    }
    if (copy_blobs(first_field))
    {
      my_message(ER_OUTOFMEMORY, ER_THD(thd,ER_OUTOFMEMORY),
                 MYF(ME_FATALERROR));
      error=0;
      goto err;
    }
    store_record(table,record[1]);

    /* Read through rest of file and mark duplicated rows deleted */
    bool found=0;
    for (;;)
    {
      if ((error= file->ha_rnd_next(record)))
      {
	if (error == HA_ERR_RECORD_DELETED)
	  continue;
	if (error == HA_ERR_END_OF_FILE)
	  break;
	goto err;
      }
      if (compare_record(table, first_field) == 0)
      {
	if ((error= file->ha_delete_row(record)))
	  goto err;
      }
      else if (!found)
      {
	found=1;
        if ((error= file->remember_rnd_pos()))
          goto err;
      }
    }
    if (!found)
      break;					// End of file
    /* Restart search on saved row */
    if ((error= file->restart_rnd_next(record)))
      goto err;
  }

  file->extra(HA_EXTRA_NO_CACHE);
  (void) file->ha_rnd_end();
  DBUG_RETURN(0);
err:
  file->extra(HA_EXTRA_NO_CACHE);
  (void) file->ha_rnd_end();
  if (error)
    file->print_error(error,MYF(0));
  DBUG_RETURN(1);
}


calc_group_buffer(JOIN *join,ORDER *group)
{
  uint key_length=0, parts=0, null_parts=0;

  if (group)
    join->group= 1;
  for (; group ; group=group->next)
  {
    Item *group_item= *group->item;
    Field *field= group_item->get_tmp_table_field();
    if (field)
    {
      enum_field_types type;
      if ((type= field->type()) == MYSQL_TYPE_BLOB)
	key_length+=MAX_BLOB_WIDTH;		// Can't be used as a key
      else if (type == MYSQL_TYPE_VARCHAR || type == MYSQL_TYPE_VAR_STRING)
        key_length+= field->field_length + HA_KEY_BLOB_LENGTH;
      else if (type == MYSQL_TYPE_BIT)
      {
        /* Bit is usually stored as a longlong key for group fields */
        key_length+= 8;                         // Big enough
      }
      else
	key_length+= field->pack_length();
    }
    else
    {
      switch (group_item->cmp_type()) {
      case REAL_RESULT:
        key_length+= sizeof(double);
        break;
      case INT_RESULT:
        key_length+= sizeof(longlong);
        break;
      case DECIMAL_RESULT:
        key_length+= my_decimal_get_binary_size(group_item->max_length -
                                                (group_item->decimals ? 1 : 0),
                                                group_item->decimals);
        break;
      case TIME_RESULT:
      {
        /*
          As items represented as DATE/TIME fields in the group buffer
          have STRING_RESULT result type, we increase the length
          by 8 as maximum pack length of such fields.
        */
        key_length+= 8;
        break;
      }
      case STRING_RESULT:
      {
        enum enum_field_types type= group_item->field_type();
        if (type == MYSQL_TYPE_BLOB)
          key_length+= MAX_BLOB_WIDTH;		// Can't be used as a key
        else
        {
          /*
            Group strings are taken as varstrings and require an length field.
            A field is not yet created by create_tmp_field()
            and the sizes should match up.
          */
          key_length+= group_item->max_length + HA_KEY_BLOB_LENGTH;
        }
        break;
      }
      default:
        /* This case should never be choosen */
        DBUG_ASSERT(0);
        my_error(ER_OUT_OF_RESOURCES, MYF(ME_FATALERROR));
      }
    }
    parts++;
    if (group_item->maybe_null)
      null_parts++;
  }
  join->tmp_table_param.group_length=key_length+null_parts;
  join->tmp_table_param.group_parts=parts;
  join->tmp_table_param.group_null_parts=null_parts;
}


bool Multiupdate_prelocking_strategy::handle_end(THD *thd)
{
  DBUG_ENTER("Multiupdate_prelocking_strategy::handle_end");
  if (done)
    DBUG_RETURN(0);

  LEX *lex= thd->lex;
  SELECT_LEX *select_lex= &lex->select_lex;
  TABLE_LIST *table_list= lex->query_tables, *tl;

  done= true;

  if (mysql_handle_derived(lex, DT_INIT) ||
      mysql_handle_derived(lex, DT_MERGE_FOR_INSERT) ||
      mysql_handle_derived(lex, DT_PREPARE))
    DBUG_RETURN(1);

  /*
    setup_tables() need for VIEWs. JOIN::prepare() will call setup_tables()
    second time, but this call will do nothing (there are check for second
    call in setup_tables()).
  */

  if (setup_tables_and_check_access(thd, &select_lex->context,
      &select_lex->top_join_list, table_list, select_lex->leaf_tables,
      FALSE, UPDATE_ACL, SELECT_ACL, TRUE))
    DBUG_RETURN(1);

  List<Item> *fields= &lex->select_lex.item_list;
  if (setup_fields_with_no_wrap(thd, Ref_ptr_array(),
                                *fields, MARK_COLUMNS_WRITE, 0, 0))
    DBUG_RETURN(1);

  // Check if we have a view in the list ...
  for (tl= table_list; tl ; tl= tl->next_local)
    if (tl->view)
      break;
  // ... and pass this knowlage in check_fields call
  if (check_fields(thd, *fields, tl != NULL ))
    DBUG_RETURN(1);

  table_map tables_for_update= thd->table_map_for_update= get_table_map(fields);

  if (unsafe_key_update(select_lex->leaf_tables, tables_for_update))
    DBUG_RETURN(1);

  /*
    Setup timestamp handling and locking mode
  */
  List_iterator<TABLE_LIST> ti(select_lex->leaf_tables);
  const bool using_lock_tables= thd->locked_tables_mode != LTM_NONE;
  while ((tl= ti++))
  {
    TABLE *table= tl->table;

    if (tl->is_jtbm())
      continue;

    /* if table will be updated then check that it is unique */
    if (table->map & tables_for_update)
    {
      if (!tl->single_table_updatable() || check_key_in_view(thd, tl))
      {
        my_error(ER_NON_UPDATABLE_TABLE, MYF(0),
                 tl->top_table()->alias.str, "UPDATE");
        DBUG_RETURN(1);
      }

      DBUG_PRINT("info",("setting table `%s` for update",
                         tl->top_table()->alias.str));
      /*
        If table will be updated we should not downgrade lock for it and
        leave it as is.
      */
      tl->updating= 1;
      if (tl->belong_to_view)
        tl->belong_to_view->updating= 1;
      if (extend_table_list(thd, tl, this, has_prelocking_list))
        DBUG_RETURN(1);
    }
    else
    {
      DBUG_PRINT("info",("setting table `%s` for read-only", tl->alias.str));
      /*
        If we are using the binary log, we need TL_READ_NO_INSERT to get
        correct order of statements. Otherwise, we use a TL_READ lock to
        improve performance.
        We don't downgrade metadata lock from SW to SR in this case as
        there is no guarantee that the same ticket is not used by
        another table instance used by this statement which is going to
        be write-locked (for example, trigger to be invoked might try
        to update this table).
        Last argument routine_modifies_data for read_lock_type_for_table()
        is ignored, as prelocking placeholder will never be set here.
      */
      DBUG_ASSERT(tl->prelocking_placeholder == false);
      thr_lock_type lock_type= read_lock_type_for_table(thd, lex, tl, true);
      if (using_lock_tables)
        tl->lock_type= lock_type;
      else
        tl->set_lock_type(thd, lock_type);
    }
  }

  /*
    Check access privileges for tables being updated or read.
    Note that unlike in the above loop we need to iterate here not only
    through all leaf tables but also through all view hierarchy.
  */

  for (tl= table_list; tl; tl= tl->next_local)
  {
    bool not_used= false;
    if (tl->is_jtbm())
      continue;
    if (multi_update_check_table_access(thd, tl, tables_for_update, &not_used))
      DBUG_RETURN(TRUE);
  }

  /* check single table update for view compound from several tables */
  for (tl= table_list; tl; tl= tl->next_local)
  {
    TABLE_LIST *for_update= 0;
    if (tl->is_jtbm())
      continue;
    if (tl->is_merged_derived() &&
        tl->check_single_table(&for_update, tables_for_update, tl))
    {
      my_error(ER_VIEW_MULTIUPDATE, MYF(0), tl->view_db.str, tl->view_name.str);
      DBUG_RETURN(1);
    }
  }

  DBUG_RETURN(0);
}

MDEV-28095 crash in multi-update and implicit grouping

disallow implicit grouping in multi-update.
explicit GROUP BY is not allowed by the grammar.


static bool multi_update_check_table_access(THD *thd, TABLE_LIST *table,
                                            table_map tables_for_update,
                                            bool *updated_arg)
{
  if (table->view)
  {
    bool updated= false;
    /*
      If it is a mergeable view then we need to check privileges on its
      underlying tables being merged (including views). We also need to
      check if any of them is updated in order to find if this view is
      updated.
      If it is a non-mergeable view then it can't be updated.
    */
    DBUG_ASSERT(table->merge_underlying_list ||
                (!table->updatable &&
                 !(table->table->map & tables_for_update)));

    for (TABLE_LIST *tbl= table->merge_underlying_list; tbl;
         tbl= tbl->next_local)
    {
      if (multi_update_check_table_access(thd, tbl, tables_for_update,
                                          &updated))
      {
        tbl->hide_view_error(thd);
        return true;
      }
    }
    if (check_table_access(thd, updated ? UPDATE_ACL: SELECT_ACL, table,
                           FALSE, 1, FALSE))
      return true;
    *updated_arg|= updated;
    /* We only need SELECT privilege for columns in the values list. */
    table->grant.want_privilege= SELECT_ACL & ~table->grant.privilege;
  }
  else
  {
    /* Must be a base or derived table. */
    const bool updated= table->table->map & tables_for_update;
    if (check_table_access(thd, updated ? UPDATE_ACL : SELECT_ACL, table,
                           FALSE, 1, FALSE))
      return true;
    *updated_arg|= updated;
    /* We only need SELECT privilege for columns in the values list. */
    if (!table->derived)
    {
      table->grant.want_privilege= SELECT_ACL & ~table->grant.privilege;
      table->table->grant.want_privilege= (SELECT_ACL &
                                           ~table->table->grant.privilege);
    }
  }
  return false;
}


int multi_update::do_updates()
{
  TABLE_LIST *cur_table;
  int local_error= 0;
  ha_rows org_updated;
  TABLE *table, *tmp_table, *err_table;
  List_iterator_fast<TABLE> check_opt_it(unupdated_check_opt_tables);
  DBUG_ENTER("multi_update::do_updates");

  do_update= 0;					// Don't retry this function
  if (!found)
    DBUG_RETURN(0);

  /*
    Update read_set to include all fields that virtual columns may depend on.
    Usually they're already in the read_set, but if the previous access
    method was keyread, only the virtual column itself will be in read_set,
    not its dependencies
  */
  while(TABLE *tbl= check_opt_it++)
  {
    if (tbl->vcol_set)
    {
      bitmap_clear_all(tbl->vcol_set);
      for (Field **vf= tbl->vfield; *vf; vf++)
      {
        if (bitmap_is_set(tbl->read_set, (*vf)->field_index))
          tbl->mark_virtual_col(*vf);
      }
    }
  }

  for (cur_table= update_tables; cur_table; cur_table= cur_table->next_local)
  {
    bool can_compare_record;
    uint offset= cur_table->shared;

    table = cur_table->table;
    if (table == table_to_update)
      continue;					// Already updated
    org_updated= updated;
    tmp_table= tmp_tables[cur_table->shared];
    tmp_table->file->extra(HA_EXTRA_CACHE);	// Change to read cache
    if (unlikely((local_error= table->file->ha_rnd_init(0))))
    {
      err_table= table;
      goto err;
    }
    table->file->extra(HA_EXTRA_NO_CACHE);
    /*
      We have to clear the base record, if we have virtual indexed
      blob fields, as some storage engines will access the blob fields
      to calculate the keys to see if they have changed. Without
      clearing the blob pointers will contain random values which can
      cause a crash.
      This is a workaround for engines that access columns not present in
      either read or write set.
    */
    if (table->vfield)
      empty_record(table);

    has_vers_fields= table->vers_check_update(*fields);

    check_opt_it.rewind();
    while(TABLE *tbl= check_opt_it++)
    {
      if (unlikely((local_error= tbl->file->ha_rnd_init(0))))
      {
        err_table= tbl;
        goto err;
      }
      tbl->file->extra(HA_EXTRA_CACHE);
    }

    /*
      Setup copy functions to copy fields from temporary table
    */
    List_iterator_fast<Item> field_it(*fields_for_table[offset]);
    Field **field;
    Copy_field *copy_field_ptr= copy_field, *copy_field_end;

    /* Skip row pointers */
    field= tmp_table->field + 1 + unupdated_check_opt_tables.elements;
    for ( ; *field ; field++)
    {
      Item_field *item= (Item_field* ) field_it++;
      (copy_field_ptr++)->set(item->field, *field, 0);
    }
    copy_field_end=copy_field_ptr;

    if (unlikely((local_error= tmp_table->file->ha_rnd_init(1))))
    {
      err_table= tmp_table;
      goto err;
    }

    can_compare_record= records_are_comparable(table);

    for (;;)
    {
      if (thd->killed && trans_safe)
      {
        thd->fatal_error();
	goto err2;
      }
      if (unlikely((local_error=
                    tmp_table->file->ha_rnd_next(tmp_table->record[0]))))
      {
	if (local_error == HA_ERR_END_OF_FILE)
	  break;
        err_table= tmp_table;
	goto err;
      }

      /* call rnd_pos() using rowids from temporary table */
      check_opt_it.rewind();
      TABLE *tbl= table;
      uint field_num= 0;
      do
      {
        DBUG_ASSERT(!tmp_table->field[field_num]->is_null());
        if (unlikely((local_error=
                      tbl->file->ha_rnd_pos(tbl->record[0],
                                            (uchar *) tmp_table->
                                            field[field_num]->ptr))))
        {
          err_table= tbl;
          goto err;
        }
        field_num++;
      } while ((tbl= check_opt_it++));

      if (table->vfield &&
          unlikely(table->update_virtual_fields(table->file,
                                                VCOL_UPDATE_INDEXED_FOR_UPDATE)))
        goto err2;

      table->status|= STATUS_UPDATED;
      store_record(table,record[1]);

      /* Copy data from temporary table to current table */
      for (copy_field_ptr=copy_field;
	   copy_field_ptr != copy_field_end;
	   copy_field_ptr++)
      {
	(*copy_field_ptr->do_copy)(copy_field_ptr);
        copy_field_ptr->to_field->set_has_explicit_value();
      }

      table->evaluate_update_default_function();
      if (table->vfield &&
          table->update_virtual_fields(table->file, VCOL_UPDATE_FOR_WRITE))
        goto err2;
      if (table->triggers &&
          table->triggers->process_triggers(thd, TRG_EVENT_UPDATE,
                                            TRG_ACTION_BEFORE, TRUE))
        goto err2;

      if (!can_compare_record || compare_record(table))
      {
        int error;
        if ((error= cur_table->view_check_option(thd, ignore)) !=
            VIEW_CHECK_OK)
        {
          if (error == VIEW_CHECK_SKIP)
            continue;
          else if (unlikely(error == VIEW_CHECK_ERROR))
          {
            thd->fatal_error();
            goto err2;
          }
        }
        if (has_vers_fields && table->versioned())
          table->vers_update_fields();

        if (unlikely((local_error=
                      table->file->ha_update_row(table->record[1],
                                                 table->record[0]))) &&
            local_error != HA_ERR_RECORD_IS_THE_SAME)
	{
	  if (!ignore ||
              table->file->is_fatal_error(local_error, HA_CHECK_ALL))
          {
            err_table= table;
            goto err;
          }
        }
        if (local_error != HA_ERR_RECORD_IS_THE_SAME)
        {
          updated++;

          if (has_vers_fields && table->versioned())
          {
            if (table->versioned(VERS_TIMESTAMP))
            {
              store_record(table, record[2]);
              if ((local_error= vers_insert_history_row(table)))
              {
                restore_record(table, record[2]);
                err_table = table;
                goto err;
              }
              restore_record(table, record[2]);
            }
            updated_sys_ver++;
          }
        }
        else
          local_error= 0;
      }

      if (table->triggers &&
          unlikely(table->triggers->process_triggers(thd, TRG_EVENT_UPDATE,
                                                     TRG_ACTION_AFTER, TRUE)))
        goto err2;
    }

    if (updated != org_updated)
    {
      if (table->file->has_transactions())
        transactional_tables= TRUE;
      else
      {
        trans_safe= FALSE;				// Can't do safe rollback
        thd->transaction.stmt.modified_non_trans_table= TRUE;
      }
    }
    (void) table->file->ha_rnd_end();
    (void) tmp_table->file->ha_rnd_end();
    check_opt_it.rewind();
    while (TABLE *tbl= check_opt_it++)
        tbl->file->ha_rnd_end();

  }
  DBUG_RETURN(0);

err:
  {
    prepare_record_for_error_message(local_error, err_table);
    err_table->file->print_error(local_error,MYF(ME_FATALERROR));
  }

err2:
  if (table->file->inited)
    (void) table->file->ha_rnd_end();
  if (tmp_table->file->inited)
    (void) tmp_table->file->ha_rnd_end();
  check_opt_it.rewind();
  while (TABLE *tbl= check_opt_it++)
  {
    if (tbl->file->inited)
      (void) tbl->file->ha_rnd_end();
  }

  if (updated != org_updated)
  {
    if (table->file->has_transactions())
      transactional_tables= TRUE;
    else
    {
      trans_safe= FALSE;
      thd->transaction.stmt.modified_non_trans_table= TRUE;
    }
  }
  DBUG_RETURN(1);
}


multi_update::initialize_tables(JOIN *join)
{
  TABLE_LIST *table_ref;
  DBUG_ENTER("initialize_tables");

  if (unlikely((thd->variables.option_bits & OPTION_SAFE_UPDATES) &&
               error_if_full_join(join)))
    DBUG_RETURN(1);
  if (join->implicit_grouping)
  {
    my_error(ER_INVALID_GROUP_FUNC_USE, MYF(0));
    DBUG_RETURN(1);
  }
  main_table=join->join_tab->table;
  table_to_update= 0;

  /* Any update has at least one pair (field, value) */
  DBUG_ASSERT(fields->elements);
  /*
   Only one table may be modified by UPDATE of an updatable view.
   For an updatable view first_table_for_update indicates this
   table.
   For a regular multi-update it refers to some updated table.
  */
  TABLE *first_table_for_update= ((Item_field *) fields->head())->field->table;

  /* Create a temporary table for keys to all tables, except main table */
  for (table_ref= update_tables; table_ref; table_ref= table_ref->next_local)
  {
    TABLE *table=table_ref->table;
    uint cnt= table_ref->shared;
    List<Item> temp_fields;
    ORDER     group;
    TMP_TABLE_PARAM *tmp_param;

    if (ignore)
      table->file->extra(HA_EXTRA_IGNORE_DUP_KEY);
    if (table == main_table)			// First table in join
    {
      if (safe_update_on_fly(thd, join->join_tab, table_ref, all_tables))
      {
	table_to_update= table;			// Update table on the fly
        has_vers_fields= table->vers_check_update(*fields);
	continue;
      }
    }
    table->prepare_for_position();
    join->map2table[table->tablenr]->keep_current_rowid= true;

    /*
      enable uncacheable flag if we update a view with check option
      and check option has a subselect, otherwise, the check option
      can be evaluated after the subselect was freed as independent
      (See full_local in JOIN::join_free()).
    */
    if (table_ref->check_option && !join->select_lex->uncacheable)
    {
      SELECT_LEX_UNIT *tmp_unit;
      SELECT_LEX *sl;
      for (tmp_unit= join->select_lex->first_inner_unit();
           tmp_unit;
           tmp_unit= tmp_unit->next_unit())
      {
        for (sl= tmp_unit->first_select(); sl; sl= sl->next_select())
        {
          if (sl->master_unit()->item)
          {
            join->select_lex->uncacheable|= UNCACHEABLE_CHECKOPTION;
            goto loop_end;
          }
        }
      }
    }
loop_end:

    if (table == first_table_for_update && table_ref->check_option)
    {
      table_map unupdated_tables= table_ref->check_option->used_tables() &
                                  ~first_table_for_update->map;
      List_iterator<TABLE_LIST> ti(*leaves);
      TABLE_LIST *tbl_ref;
      while ((tbl_ref= ti++) && unupdated_tables)
      {
        if (unupdated_tables & tbl_ref->table->map)
          unupdated_tables&= ~tbl_ref->table->map;
        else
          continue;
        if (unupdated_check_opt_tables.push_back(tbl_ref->table))
          DBUG_RETURN(1);
      }
    }

    tmp_param= tmp_table_param+cnt;

    /*
      Create a temporary table to store all fields that are changed for this
      table. The first field in the temporary table is a pointer to the
      original row so that we can find and update it. For the updatable
      VIEW a few following fields are rowids of tables used in the CHECK
      OPTION condition.
    */

    List_iterator_fast<TABLE> tbl_it(unupdated_check_opt_tables);
    TABLE *tbl= table;
    do
    {
      LEX_CSTRING field_name;
      field_name.str= tbl->alias.c_ptr();
      field_name.length= strlen(field_name.str);
      /*
        Signal each table (including tables referenced by WITH CHECK OPTION
        clause) for which we will store row position in the temporary table
        that we need a position to be read first.
      */
      tbl->prepare_for_position();
      join->map2table[tbl->tablenr]->keep_current_rowid= true;

      Item_temptable_rowid *item=
        new (thd->mem_root) Item_temptable_rowid(tbl);
      if (!item)
         DBUG_RETURN(1);
      item->fix_fields(thd, 0);
      if (temp_fields.push_back(item, thd->mem_root))
        DBUG_RETURN(1);
    } while ((tbl= tbl_it++));

    temp_fields.append(fields_for_table[cnt]);

    /* Make an unique key over the first field to avoid duplicated updates */
    bzero((char*) &group, sizeof(group));
    group.direction= ORDER::ORDER_ASC;
    group.item= (Item**) temp_fields.head_ref();

    tmp_param->quick_group= 1;
    tmp_param->field_count= temp_fields.elements;
    tmp_param->func_count=  temp_fields.elements - 1;
    calc_group_buffer(tmp_param, &group);
    /* small table, ignore SQL_BIG_TABLES */
    my_bool save_big_tables= thd->variables.big_tables;
    thd->variables.big_tables= FALSE;
    tmp_tables[cnt]=create_tmp_table(thd, tmp_param, temp_fields,
                                     (ORDER*) &group, 0, 0,
                                     TMP_TABLE_ALL_COLUMNS, HA_POS_ERROR, &empty_clex_str);
    thd->variables.big_tables= save_big_tables;
    if (!tmp_tables[cnt])
      DBUG_RETURN(1);
    tmp_tables[cnt]->file->extra(HA_EXTRA_WRITE_CACHE);
  }
  join->tmp_table_keep_current_rowid= TRUE;
  DBUG_RETURN(0);
}


int multi_update::send_data(List<Item> &not_used_values)
{
  TABLE_LIST *cur_table;
  DBUG_ENTER("multi_update::send_data");

  for (cur_table= update_tables; cur_table; cur_table= cur_table->next_local)
  {
    int error= 0;
    TABLE *table= cur_table->table;
    uint offset= cur_table->shared;
    /*
      Check if we are using outer join and we didn't find the row
      or if we have already updated this row in the previous call to this
      function.

      The same row may be presented here several times in a join of type
      UPDATE t1 FROM t1,t2 SET t1.a=t2.a

      In this case we will do the update for the first found row combination.
      The join algorithm guarantees that we will not find the a row in
      t1 several times.
    */
    if (table->status & (STATUS_NULL_ROW | STATUS_UPDATED))
      continue;

    if (table == table_to_update)
    {
      /*
        We can use compare_record() to optimize away updates if
        the table handler is returning all columns OR if
        if all updated columns are read
      */
      bool can_compare_record;
      can_compare_record= records_are_comparable(table);

      table->status|= STATUS_UPDATED;
      store_record(table,record[1]);

      if (fill_record_n_invoke_before_triggers(thd, table,
                                               *fields_for_table[offset],
                                               *values_for_table[offset], 0,
                                               TRG_EVENT_UPDATE))
	DBUG_RETURN(1);
      /*
        Reset the table->auto_increment_field_not_null as it is valid for
        only one row.
      */
      table->auto_increment_field_not_null= FALSE;
      found++;
      if (!can_compare_record || compare_record(table))
      {

        if ((error= cur_table->view_check_option(thd, ignore)) !=
            VIEW_CHECK_OK)
        {
          found--;
          if (error == VIEW_CHECK_SKIP)
            continue;
          else if (unlikely(error == VIEW_CHECK_ERROR))
            DBUG_RETURN(1);
        }
        if (unlikely(!updated++))
        {
          /*
            Inform the main table that we are going to update the table even
            while we may be scanning it.  This will flush the read cache
            if it's used.
          */
          main_table->file->extra(HA_EXTRA_PREPARE_FOR_UPDATE);
        }
        if (unlikely((error=table->file->ha_update_row(table->record[1],
                                                       table->record[0]))) &&
            error != HA_ERR_RECORD_IS_THE_SAME)
        {
          updated--;
          if (!ignore ||
              table->file->is_fatal_error(error, HA_CHECK_ALL))
            goto error;
        }
        else
        {
          if (unlikely(error == HA_ERR_RECORD_IS_THE_SAME))
          {
            error= 0;
            updated--;
          }
          else if (has_vers_fields && table->versioned(VERS_TRX_ID))
          {
            updated_sys_ver++;
          }
          /* non-transactional or transactional table got modified   */
          /* either multi_update class' flag is raised in its branch */
          if (table->file->has_transactions())
            transactional_tables= TRUE;
          else
          {
            trans_safe= FALSE;
            thd->transaction.stmt.modified_non_trans_table= TRUE;
          }
        }
      }
      if (has_vers_fields && table->versioned(VERS_TIMESTAMP))
      {
        store_record(table, record[2]);
        if (unlikely(error= vers_insert_history_row(table)))
        {
          restore_record(table, record[2]);
          goto error;
        }
        restore_record(table, record[2]);
        updated_sys_ver++;
      }
      if (table->triggers &&
          unlikely(table->triggers->process_triggers(thd, TRG_EVENT_UPDATE,
                                                     TRG_ACTION_AFTER, TRUE)))
        DBUG_RETURN(1);
    }
    else
    {
      TABLE *tmp_table= tmp_tables[offset];
      if (copy_funcs(tmp_table_param[offset].items_to_copy, thd))
        DBUG_RETURN(1);
      /* rowid field is NULL if join tmp table has null row from outer join */
      if (tmp_table->field[0]->is_null())
        continue;
      /* Store regular updated fields in the row. */
      DBUG_ASSERT(1 + unupdated_check_opt_tables.elements ==
                  tmp_table_param[offset].func_count);
      fill_record(thd, tmp_table,
                  tmp_table->field + 1 + unupdated_check_opt_tables.elements,
                  *values_for_table[offset], TRUE, FALSE);

      /* Write row, ignoring duplicated updates to a row */
      error= tmp_table->file->ha_write_tmp_row(tmp_table->record[0]);
      found++;
      if (unlikely(error))
      {
        found--;
        if (error != HA_ERR_FOUND_DUPP_KEY &&
            error != HA_ERR_FOUND_DUPP_UNIQUE)
        {
          if (create_internal_tmp_table_from_heap(thd, tmp_table,
                                                  tmp_table_param[offset].start_recinfo,
                                                  &tmp_table_param[offset].recinfo,
                                                  error, 1, NULL))
          {
            do_update= 0;
            DBUG_RETURN(1);			// Not a table_is_full error
          }
          found++;
        }
      }
    }
    continue;
error:
    DBUG_ASSERT(error > 0);
    /*
      If (ignore && error == is ignorable) we don't have to
      do anything; otherwise...
    */
    myf flags= 0;

    if (table->file->is_fatal_error(error, HA_CHECK_ALL))
      flags|= ME_FATALERROR; /* Other handler errors are fatal */

    prepare_record_for_error_message(error, table);
    table->file->print_error(error,MYF(flags));
    DBUG_RETURN(1);
  } // for (cur_table)
  DBUG_RETURN(0);
}


static TABLE *item_rowid_table(Item *item)
{
  if (item->type() != Item::FUNC_ITEM)
    return NULL;
  Item_func *func= (Item_func *)item;
  if (func->functype() != Item_func::TEMPTABLE_ROWID)
    return NULL;
  Item_temptable_rowid *itr= (Item_temptable_rowid *)func;
  return itr->table;
}


bool multi_update::send_eof()
{
  char buff[STRING_BUFFER_USUAL_SIZE];
  ulonglong id;
  killed_state killed_status= NOT_KILLED;
  DBUG_ENTER("multi_update::send_eof");
  THD_STAGE_INFO(thd, stage_updating_reference_tables);

  /*
     Does updates for the last n - 1 tables, returns 0 if ok;
     error takes into account killed status gained in do_updates()
  */
  int local_error= thd->is_error();
  if (likely(!local_error))
    local_error = (table_count) ? do_updates() : 0;
  /*
    if local_error is not set ON until after do_updates() then
    later carried out killing should not affect binlogging.
  */
  killed_status= (local_error == 0) ? NOT_KILLED : thd->killed;
  THD_STAGE_INFO(thd, stage_end);

  /* We must invalidate the query cache before binlog writing and
  ha_autocommit_... */

  if (updated)
  {
    query_cache_invalidate3(thd, update_tables, 1);
  }
  /*
    Write the SQL statement to the binlog if we updated
    rows and we succeeded or if we updated some non
    transactional tables.

    The query has to binlog because there's a modified non-transactional table
    either from the query's list or via a stored routine: bug#13270,23333
  */

  if (thd->transaction.stmt.modified_non_trans_table)
    thd->transaction.all.modified_non_trans_table= TRUE;
  thd->transaction.all.m_unsafe_rollback_flags|=
    (thd->transaction.stmt.m_unsafe_rollback_flags & THD_TRANS::DID_WAIT);

  if (likely(local_error == 0 ||
             thd->transaction.stmt.modified_non_trans_table))
  {
    if (WSREP_EMULATE_BINLOG(thd) || mysql_bin_log.is_open())
    {
      int errcode= 0;
      if (likely(local_error == 0))
        thd->clear_error();
      else
        errcode= query_error_code(thd, killed_status == NOT_KILLED);

      bool force_stmt= false;
      for (TABLE *table= all_tables->table; table; table= table->next)
      {
        if (table->versioned(VERS_TRX_ID))
        {
          force_stmt= true;
          break;
        }
      }
      enum_binlog_format save_binlog_format;
      save_binlog_format= thd->get_current_stmt_binlog_format();
      if (force_stmt)
        thd->set_current_stmt_binlog_format_stmt();

      if (thd->binlog_query(THD::ROW_QUERY_TYPE, thd->query(),
                            thd->query_length(), transactional_tables, FALSE,
                            FALSE, errcode) > 0)
	local_error= 1;				// Rollback update
      thd->set_current_stmt_binlog_format(save_binlog_format);
    }
  }
  DBUG_ASSERT(trans_safe || !updated ||
              thd->transaction.stmt.modified_non_trans_table);

  if (likely(local_error != 0))
    error_handled= TRUE; // to force early leave from ::abort_result_set()

  if (unlikely(local_error > 0)) // if the above log write did not fail ...
  {
    /* Safety: If we haven't got an error before (can happen in do_updates) */
    my_message(ER_UNKNOWN_ERROR, "An error occurred in multi-table update",
	       MYF(0));
    DBUG_RETURN(TRUE);
  }

  if (!thd->lex->analyze_stmt)
  {
    id= thd->arg_of_last_insert_id_function ?
    thd->first_successful_insert_id_in_prev_stmt : 0;
    my_snprintf(buff, sizeof(buff), ER_THD(thd, ER_UPDATE_INFO),
                (ulong) found, (ulong) updated, (ulong) thd->cuted_fields);
    ::my_ok(thd, (thd->client_capabilities & CLIENT_FOUND_ROWS) ? found : updated,
            id, buff);
  }
  DBUG_RETURN(FALSE);
}


static bool safe_update_on_fly(THD *thd, JOIN_TAB *join_tab,
                               TABLE_LIST *table_ref, TABLE_LIST *all_tables)
{
  TABLE *table= join_tab->table;
  if (unique_table(thd, table_ref, all_tables, 0))
    return 0;
  if (join_tab->join->order) // FIXME this is probably too strong
    return 0;
  switch (join_tab->type) {
  case JT_SYSTEM:
  case JT_CONST:
  case JT_EQ_REF:
    return TRUE;				// At most one matching row
  case JT_REF:
  case JT_REF_OR_NULL:
    return !is_key_used(table, join_tab->ref.key, table->write_set);
  case JT_ALL:
    if (bitmap_is_overlapping(&table->tmp_set, table->write_set))
      return FALSE;
    /* If range search on index */
    if (join_tab->quick)
      return !join_tab->quick->is_keys_used(table->write_set);
    /* If scanning in clustered key */
    if ((table->file->ha_table_flags() & HA_PRIMARY_KEY_IN_READ_INDEX) &&
	table->s->primary_key < MAX_KEY)
      return !is_key_used(table, table->s->primary_key, table->write_set);
    return TRUE;
  default:
    break;					// Avoid compiler warning
  }
  return FALSE;

}


static table_map get_table_map(List<Item> *items)
{
  List_iterator_fast<Item> item_it(*items);
  Item_field *item;
  table_map map= 0;

  while ((item= (Item_field *) item_it++))
    map|= item->all_used_tables();
  DBUG_PRINT("info", ("table_map: 0x%08lx", (long) map));
  return map;
}


bool TABLE::vers_check_update(List<Item> &items)
{
  List_iterator<Item> it(items);
  if (!versioned_write())
    return false;

  while (Item *item= it++)
  {
    if (Item_field *item_field= item->field_for_view_update())
    {
      Field *field= item_field->field;
      if (field->table == this && !field->vers_update_unversioned())
      {
        no_cache= true;
        return true;
      }
    }
  }
  return false;
}


bool records_are_comparable(const TABLE *table) {
  return !table->versioned(VERS_TRX_ID) &&
          (((table->file->ha_table_flags() & HA_PARTIAL_COLUMN_READ) == 0) ||
           bitmap_is_subset(table->write_set, table->read_set));
}


static bool check_fields(THD *thd, List<Item> &items, bool update_view)
{
  Item *item;
  if (update_view)
  {
    List_iterator<Item> it(items);
    Item_field *field;
    while ((item= it++))
    {
      if (!(field= item->field_for_view_update()))
      {
        /* item has name, because it comes from VIEW SELECT list */
        my_error(ER_NONUPDATEABLE_COLUMN, MYF(0), item->name.str);
        return TRUE;
      }
      /*
        we make temporary copy of Item_field, to avoid influence of changing
        result_field on Item_ref which refer on this field
      */
      thd->change_item_tree(it.ref(),
                            new (thd->mem_root) Item_field(thd, field));
    }
  }

  if (thd->variables.sql_mode & MODE_SIMULTANEOUS_ASSIGNMENT)
  {
    // Make sure that a column is updated only once
    List_iterator_fast<Item> it(items);
    while ((item= it++))
    {
      item->field_for_view_update()->field->clear_has_explicit_value();
    }
    it.rewind();
    while ((item= it++))
    {
      Field *f= item->field_for_view_update()->field;
      if (f->has_explicit_value())
      {
        my_error(ER_UPDATED_COLUMN_ONLY_ONCE, MYF(0),
                 *(f->table_name), f->field_name.str);
        return TRUE;
      }
      f->set_has_explicit_value();
    }
  }
  return FALSE;
}


bool check_unique_table(THD *thd, TABLE_LIST *table_list)
{
  TABLE_LIST *duplicate;
  DBUG_ENTER("check_unique_table");
  if ((duplicate= unique_table(thd, table_list, table_list->next_global, 0)))
  {
    update_non_unique_table_error(table_list, "UPDATE", duplicate);
    DBUG_RETURN(TRUE);
  }
  DBUG_RETURN(FALSE);
}


int multi_update::prepare2(JOIN *join)
{
  if (!join->need_tmp || !join->tmp_table_keep_current_rowid)
    return 0;

  // there cannot be many tmp tables in multi-update
  JOIN_TAB *tmptab= join->join_tab + join->exec_join_tab_cnt();

  for (Item **it= tmptab->tmp_table_param->items_to_copy; *it ; it++)
  {
    TABLE *tbl= item_rowid_table(*it);
    if (!tbl)
      continue;
    for (uint i= 0; i < table_count; i++)
    {
      for (Item **it2= tmp_table_param[i].items_to_copy; *it2; it2++)
      {
        if (item_rowid_table(*it2) != tbl)
          continue;
        Item *fld= new (thd->mem_root)
                        Item_field(thd, (*it)->get_tmp_table_field());
        if (!fld)
          return 1;
        fld->set_result_field((*it2)->get_tmp_table_field());
        *it2= fld;
      }
    }
  }
  return 0;
}


int mysql_update(THD *thd,
                 TABLE_LIST *table_list,
                 List<Item> &fields,
		 List<Item> &values,
                 COND *conds,
                 uint order_num, ORDER *order,
                 ha_rows limit,
                 bool ignore,
                 ha_rows *found_return, ha_rows *updated_return)
{
  bool		using_limit= limit != HA_POS_ERROR;
  bool          safe_update= (thd->variables.option_bits & OPTION_SAFE_UPDATES)
                             && !thd->lex->describe;
  bool          used_key_is_modified= FALSE, transactional_table;
  bool          will_batch= FALSE;
  bool		can_compare_record;
  int           res;
  int		error, loc_error;
  ha_rows       dup_key_found;
  bool          need_sort= TRUE;
  bool          reverse= FALSE;
#ifndef NO_EMBEDDED_ACCESS_CHECKS
  uint		want_privilege;
#endif
  uint          table_count= 0;
  ha_rows	updated, found;
  key_map	old_covering_keys;
  TABLE		*table;
  SQL_SELECT	*select= NULL;
  SORT_INFO     *file_sort= 0;
  READ_RECORD	info;
  SELECT_LEX    *select_lex= &thd->lex->select_lex;
  ulonglong     id;
  List<Item> all_fields;
  killed_state killed_status= NOT_KILLED;
  bool has_triggers, binlog_is_row, do_direct_update= FALSE;
  Update_plan query_plan(thd->mem_root);
  Explain_update *explain;
  TABLE_LIST *update_source_table;
  query_plan.index= MAX_KEY;
  query_plan.using_filesort= FALSE;

  // For System Versioning (may need to insert new fields to a table).
  ha_rows updated_sys_ver= 0;

  DBUG_ENTER("mysql_update");

  create_explain_query(thd->lex, thd->mem_root);
  if (open_tables(thd, &table_list, &table_count, 0))
    DBUG_RETURN(1);

  /* Prepare views so they are handled correctly */
  if (mysql_handle_derived(thd->lex, DT_INIT))
    DBUG_RETURN(1);

  if (((update_source_table=unique_table(thd, table_list,
                                        table_list->next_global, 0)) ||
        table_list->is_multitable()))
  {
    DBUG_ASSERT(update_source_table || table_list->view != 0);
    DBUG_PRINT("info", ("Switch to multi-update"));
    /* pass counter value */
    thd->lex->table_count= table_count;
    /* convert to multiupdate */
    DBUG_RETURN(2);
  }
  if (lock_tables(thd, table_list, table_count, 0))
    DBUG_RETURN(1);

  (void) read_statistics_for_tables_if_needed(thd, table_list);

  THD_STAGE_INFO(thd, stage_init_update);
  if (table_list->handle_derived(thd->lex, DT_MERGE_FOR_INSERT))
    DBUG_RETURN(1);
  if (table_list->handle_derived(thd->lex, DT_PREPARE))
    DBUG_RETURN(1);

  table= table_list->table;

  if (!table_list->single_table_updatable())
  {
    my_error(ER_NON_UPDATABLE_TABLE, MYF(0), table_list->alias.str, "UPDATE");
    DBUG_RETURN(1);
  }
  query_plan.updating_a_view= MY_TEST(table_list->view);

  /* Calculate "table->covering_keys" based on the WHERE */
  table->covering_keys= table->s->keys_in_use;
  table->quick_keys.clear_all();

  query_plan.select_lex= &thd->lex->select_lex;
  query_plan.table= table;
#ifndef NO_EMBEDDED_ACCESS_CHECKS
  /* Force privilege re-checking for views after they have been opened. */
  want_privilege= (table_list->view ? UPDATE_ACL :
                   table_list->grant.want_privilege);
#endif
  promote_select_describe_flag_if_needed(thd->lex);

  if (mysql_prepare_update(thd, table_list, &conds, order_num, order))
    DBUG_RETURN(1);

  old_covering_keys= table->covering_keys;		// Keys used in WHERE
  /* Check the fields we are going to modify */
#ifndef NO_EMBEDDED_ACCESS_CHECKS
  table_list->grant.want_privilege= table->grant.want_privilege= want_privilege;
  table_list->register_want_access(want_privilege);
#endif
  /* 'Unfix' fields to allow correct marking by the setup_fields function. */
  if (table_list->is_view())
    unfix_fields(fields);

  if (setup_fields_with_no_wrap(thd, Ref_ptr_array(),
                                fields, MARK_COLUMNS_WRITE, 0, 0))
    DBUG_RETURN(1);                     /* purecov: inspected */
  if (check_fields(thd, fields, table_list->view))
  {
    DBUG_RETURN(1);
  }
  bool has_vers_fields= table->vers_check_update(fields);
  if (check_key_in_view(thd, table_list))
  {
    my_error(ER_NON_UPDATABLE_TABLE, MYF(0), table_list->alias.str, "UPDATE");
    DBUG_RETURN(1);
  }

  if (table->default_field)
    table->mark_default_fields_for_write(false);

#ifndef NO_EMBEDDED_ACCESS_CHECKS
  /* Check values */
  table_list->grant.want_privilege= table->grant.want_privilege=
    (SELECT_ACL & ~table->grant.privilege);
#endif
  if (setup_fields(thd, Ref_ptr_array(), values, MARK_COLUMNS_READ, 0, NULL, 0))
  {
    free_underlaid_joins(thd, select_lex);
    DBUG_RETURN(1);				/* purecov: inspected */
  }

  if (check_unique_table(thd, table_list))
    DBUG_RETURN(TRUE);

  switch_to_nullable_trigger_fields(fields, table);
  switch_to_nullable_trigger_fields(values, table);

  /* Apply the IN=>EXISTS transformation to all subqueries and optimize them */
  if (select_lex->optimize_unflattened_subqueries(false))
    DBUG_RETURN(TRUE);

  if (select_lex->inner_refs_list.elements &&
    fix_inner_refs(thd, all_fields, select_lex, select_lex->ref_pointer_array))
    DBUG_RETURN(1);

  if (conds)
  {
    Item::cond_result cond_value;
    conds= conds->remove_eq_conds(thd, &cond_value, true);
    if (cond_value == Item::COND_FALSE)
    {
      limit= 0;                                   // Impossible WHERE
      query_plan.set_impossible_where();
      if (thd->lex->describe || thd->lex->analyze_stmt)
        goto produce_explain_and_leave;
    }
  }

  // Don't count on usage of 'only index' when calculating which key to use
  table->covering_keys.clear_all();

#ifdef WITH_PARTITION_STORAGE_ENGINE
  if (prune_partitions(thd, table, conds))
  {
    free_underlaid_joins(thd, select_lex);

    query_plan.set_no_partitions();
    if (thd->lex->describe || thd->lex->analyze_stmt)
      goto produce_explain_and_leave;
    if (thd->is_error())
      DBUG_RETURN(1);

    my_ok(thd);				// No matching records
    DBUG_RETURN(0);
  }
#endif
  /* Update the table->file->stats.records number */
  table->file->info(HA_STATUS_VARIABLE | HA_STATUS_NO_LOCK);
  set_statistics_for_table(thd, table);

  select= make_select(table, 0, 0, conds, (SORT_INFO*) 0, 0, &error);
  if (unlikely(error || !limit || thd->is_error() ||
               (select && select->check_quick(thd, safe_update, limit))))
  {
    query_plan.set_impossible_where();
    if (thd->lex->describe || thd->lex->analyze_stmt)
      goto produce_explain_and_leave;

    delete select;
    free_underlaid_joins(thd, select_lex);
    /*
      There was an error or the error was already sent by
      the quick select evaluation.
      TODO: Add error code output parameter to Item::val_xxx() methods.
      Currently they rely on the user checking DA for
      errors when unwinding the stack after calling Item::val_xxx().
    */
    if (error || thd->is_error())
    {
      DBUG_RETURN(1);				// Error in where
    }
    my_ok(thd);				// No matching records
    DBUG_RETURN(0);
  }

  /* If running in safe sql mode, don't allow updates without keys */
  if (!select || !select->quick)
  {
    thd->set_status_no_index_used();
    if (safe_update && !using_limit)
    {
      my_message(ER_UPDATE_WITHOUT_KEY_IN_SAFE_MODE,
		 ER_THD(thd, ER_UPDATE_WITHOUT_KEY_IN_SAFE_MODE), MYF(0));
      goto err;
    }
  }
  if (unlikely(init_ftfuncs(thd, select_lex, 1)))
    goto err;

  table->mark_columns_needed_for_update();

  table->update_const_key_parts(conds);
  order= simple_remove_const(order, conds);
  query_plan.scanned_rows= select? select->records: table->file->stats.records;

  if (select && select->quick && select->quick->unique_key_range())
  {
    /* Single row select (always "ordered"): Ok to use with key field UPDATE */
    need_sort= FALSE;
    query_plan.index= MAX_KEY;
    used_key_is_modified= FALSE;
  }
  else
  {
    ha_rows scanned_limit= query_plan.scanned_rows;
    query_plan.index= get_index_for_order(order, table, select, limit,
                                          &scanned_limit, &need_sort,
                                          &reverse);
    if (!need_sort)
      query_plan.scanned_rows= scanned_limit;

    if (select && select->quick)
    {
      DBUG_ASSERT(need_sort || query_plan.index == select->quick->index);
      used_key_is_modified= (!select->quick->unique_key_range() &&
                             select->quick->is_keys_used(table->write_set));
    }
    else
    {
      if (need_sort)
      {
        /* Assign table scan index to check below for modified key fields: */
        query_plan.index= table->file->key_used_on_scan;
      }
      if (query_plan.index != MAX_KEY)
      {
        /* Check if we are modifying a key that we are used to search with: */
        used_key_is_modified= is_key_used(table, query_plan.index,
                                          table->write_set);
      }
    }
  }

  /*
    Query optimization is finished at this point.
     - Save the decisions in the query plan
     - if we're running EXPLAIN UPDATE, get out
  */
  query_plan.select= select;
  query_plan.possible_keys= select? select->possible_keys: key_map(0);

  if (used_key_is_modified || order ||
      partition_key_modified(table, table->write_set))
  {
    if (order && need_sort)
      query_plan.using_filesort= true;
    else
      query_plan.using_io_buffer= true;
  }

  /*
    Ok, we have generated a query plan for the UPDATE.
     - if we're running EXPLAIN UPDATE, goto produce explain output
     - otherwise, execute the query plan
  */
  if (thd->lex->describe)
    goto produce_explain_and_leave;
  if (!(explain= query_plan.save_explain_update_data(query_plan.mem_root, thd)))
    goto err;

  ANALYZE_START_TRACKING(&explain->command_tracker);

  DBUG_EXECUTE_IF("show_explain_probe_update_exec_start",
                  dbug_serve_apcs(thd, 1););

  has_triggers= (table->triggers &&
                 (table->triggers->has_triggers(TRG_EVENT_UPDATE,
                                                TRG_ACTION_BEFORE) ||
                 table->triggers->has_triggers(TRG_EVENT_UPDATE,
                                               TRG_ACTION_AFTER)));
  DBUG_PRINT("info", ("has_triggers: %s", has_triggers ? "TRUE" : "FALSE"));
  binlog_is_row= thd->is_current_stmt_binlog_format_row();
  DBUG_PRINT("info", ("binlog_is_row: %s", binlog_is_row ? "TRUE" : "FALSE"));

  if (!(select && select->quick))
    status_var_increment(thd->status_var.update_scan_count);

  /*
    We can use direct update (update that is done silently in the handler)
    if none of the following conditions are true:
    - There are triggers
    - There is binary logging
    - using_io_buffer
      - This means that the partition changed or the key we want
        to use for scanning the table is changed
    - ignore is set
      - Direct updates don't return the number of ignored rows
    - There is a virtual not stored column in the WHERE clause
    - Changing a field used by a stored virtual column, which
      would require the column to be recalculated.
    - ORDER BY or LIMIT
      - As this requires the rows to be updated in a specific order
      - Note that Spider can handle ORDER BY and LIMIT in a cluster with
        one data node.  These conditions are therefore checked in
        direct_update_rows_init().
    - Update fields include a unique timestamp field
      - The storage engine may not be able to avoid false duplicate key
        errors.  This condition is checked in direct_update_rows_init().

    Direct update does not require a WHERE clause

    Later we also ensure that we are only using one table (no sub queries)
  */
  if ((table->file->ha_table_flags() & HA_CAN_DIRECT_UPDATE_AND_DELETE) &&
      !has_triggers && !binlog_is_row &&
      !query_plan.using_io_buffer && !ignore &&
      !table->check_virtual_columns_marked_for_read() &&
      !table->check_virtual_columns_marked_for_write())
  {
    DBUG_PRINT("info", ("Trying direct update"));
    bool use_direct_update= !select || !select->cond;
    if (!use_direct_update &&
        (select->cond->used_tables() & ~RAND_TABLE_BIT) == table->map)
    {
      DBUG_ASSERT(!table->file->pushed_cond);
      if (!table->file->cond_push(select->cond))
      {
        use_direct_update= TRUE;
        table->file->pushed_cond= select->cond;
      }
    }

    if (use_direct_update &&
        !table->file->info_push(INFO_KIND_UPDATE_FIELDS, &fields) &&
        !table->file->info_push(INFO_KIND_UPDATE_VALUES, &values) &&
        !table->file->direct_update_rows_init(&fields))
    {
      do_direct_update= TRUE;

      /* Direct update is not using_filesort and is not using_io_buffer */
      goto update_begin;
    }
  }

  if (query_plan.using_filesort || query_plan.using_io_buffer)
  {
    /*
      We can't update table directly;  We must first search after all
      matching rows before updating the table!

      note: We avoid sorting if we sort on the used index
    */
    if (query_plan.using_filesort)
    {
      /*
	Doing an ORDER BY;  Let filesort find and sort the rows we are going
	to update
        NOTE: filesort will call table->prepare_for_position()
      */
      Filesort fsort(order, limit, true, select);

      Filesort_tracker *fs_tracker=
        thd->lex->explain->get_upd_del_plan()->filesort_tracker;

      if (!(file_sort= filesort(thd, table, &fsort, fs_tracker)))
	goto err;
      thd->inc_examined_row_count(file_sort->examined_rows);

      /*
	Filesort has already found and selected the rows we want to update,
	so we don't need the where clause
      */
      delete select;
      select= 0;
    }
    else
    {
      MY_BITMAP *save_read_set= table->read_set;
      MY_BITMAP *save_write_set= table->write_set;

      if (query_plan.index < MAX_KEY && old_covering_keys.is_set(query_plan.index))
        table->prepare_for_keyread(query_plan.index);
      else
        table->use_all_columns();

      /*
	We are doing a search on a key that is updated. In this case
	we go trough the matching rows, save a pointer to them and
	update these in a separate loop based on the pointer.
      */
      explain->buf_tracker.on_scan_init();
      IO_CACHE tempfile;
      if (open_cached_file(&tempfile, mysql_tmpdir,TEMP_PREFIX,
			   DISK_BUFFER_SIZE, MYF(MY_WME)))
	goto err;

      /* If quick select is used, initialize it before retrieving rows. */
      if (select && select->quick && select->quick->reset())
      {
        close_cached_file(&tempfile);
        goto err;
      }

      table->file->try_semi_consistent_read(1);

      /*
        When we get here, we have one of the following options:
        A. query_plan.index == MAX_KEY
           This means we should use full table scan, and start it with
           init_read_record call
        B. query_plan.index != MAX_KEY
           B.1 quick select is used, start the scan with init_read_record
           B.2 quick select is not used, this is full index scan (with LIMIT)
           Full index scan must be started with init_read_record_idx
      */

      if (query_plan.index == MAX_KEY || (select && select->quick))
        error= init_read_record(&info, thd, table, select, NULL, 0, 1, FALSE);
      else
        error= init_read_record_idx(&info, thd, table, 1, query_plan.index,
                                    reverse);

      if (unlikely(error))
      {
        close_cached_file(&tempfile);
        goto err;
      }

      THD_STAGE_INFO(thd, stage_searching_rows_for_update);
      ha_rows tmp_limit= limit;

      while (likely(!(error=info.read_record())) && likely(!thd->killed))
      {
        explain->buf_tracker.on_record_read();
        thd->inc_examined_row_count(1);
	if (!select || (error= select->skip_record(thd)) > 0)
	{
          if (table->file->ha_was_semi_consistent_read())
	    continue;  /* repeat the read of the same row if it still exists */

          explain->buf_tracker.on_record_after_where();
	  table->file->position(table->record[0]);
	  if (unlikely(my_b_write(&tempfile,table->file->ref,
                                  table->file->ref_length)))
	  {
	    error=1; /* purecov: inspected */
	    break; /* purecov: inspected */
	  }
	  if (!--limit && using_limit)
	  {
	    error= -1;
	    break;
	  }
	}
	else
        {
          /*
            Don't try unlocking the row if skip_record reported an
            error since in this case the transaction might have been
            rolled back already.
          */
          if (unlikely(error < 0))
          {
            /* Fatal error from select->skip_record() */
            error= 1;
            break;
          }
          else
            table->file->unlock_row();
        }
      }
      if (unlikely(thd->killed) && !error)
	error= 1;				// Aborted
      limit= tmp_limit;
      table->file->try_semi_consistent_read(0);
      end_read_record(&info);

      /* Change select to use tempfile */
      if (select)
      {
	delete select->quick;
	if (select->free_cond)
	  delete select->cond;
	select->quick=0;
	select->cond=0;
      }
      else
      {
	if (!(select= new SQL_SELECT))
          goto err;
	select->head=table;
      }

      if (unlikely(reinit_io_cache(&tempfile,READ_CACHE,0L,0,0)))
	error= 1; /* purecov: inspected */
      select->file= tempfile;			// Read row ptrs from this file
       if (unlikely(error >= 0))
	goto err;

      table->file->ha_end_keyread();
      table->column_bitmaps_set(save_read_set, save_write_set);
    }
  }

update_begin:
  if (ignore)
    table->file->extra(HA_EXTRA_IGNORE_DUP_KEY);

  if (select && select->quick && select->quick->reset())
    goto err;
  table->file->try_semi_consistent_read(1);
  if (init_read_record(&info, thd, table, select, file_sort, 0, 1, FALSE))
    goto err;

  updated= found= 0;
  /*
    Generate an error (in TRADITIONAL mode) or warning
    when trying to set a NOT NULL field to NULL.
  */
  thd->count_cuted_fields= CHECK_FIELD_WARN;
  thd->cuted_fields=0L;

  transactional_table= table->file->has_transactions();
  thd->abort_on_warning= !ignore && thd->is_strict_mode();

  if (do_direct_update)
  {
    /* Direct updating is supported */
    DBUG_PRINT("info", ("Using direct update"));
    table->reset_default_fields();
    if (unlikely(!(error= table->file->ha_direct_update_rows(&updated))))
      error= -1;
    found= updated;
    goto update_end;
  }

  if ((table->file->ha_table_flags() & HA_CAN_FORCE_BULK_UPDATE) &&
      !table->prepare_triggers_for_update_stmt_or_event())
    will_batch= !table->file->start_bulk_update();

  /*
    Assure that we can use position()
    if we need to create an error message.
  */
  if (table->file->ha_table_flags() & HA_PARTIAL_COLUMN_READ)
    table->prepare_for_position();

  table->reset_default_fields();

  /*
    We can use compare_record() to optimize away updates if
    the table handler is returning all columns OR if
    if all updated columns are read
  */
  can_compare_record= records_are_comparable(table);
  explain->tracker.on_scan_init();

  THD_STAGE_INFO(thd, stage_updating);
  while (!(error=info.read_record()) && !thd->killed)
  {
    explain->tracker.on_record_read();
    thd->inc_examined_row_count(1);
    if (!select || select->skip_record(thd) > 0)
    {
      if (table->file->ha_was_semi_consistent_read())
        continue;  /* repeat the read of the same row if it still exists */

      explain->tracker.on_record_after_where();
      store_record(table,record[1]);

      if (fill_record_n_invoke_before_triggers(thd, table, fields, values, 0,
                                               TRG_EVENT_UPDATE))
        break; /* purecov: inspected */

      found++;

      if (!can_compare_record || compare_record(table))
      {
        if ((res= table_list->view_check_option(thd, ignore)) !=
            VIEW_CHECK_OK)
        {
          found--;
          if (res == VIEW_CHECK_SKIP)
            continue;
          else if (res == VIEW_CHECK_ERROR)
          {
            error= 1;
            break;
          }
        }
        if (will_batch)
        {
          /*
            Typically a batched handler can execute the batched jobs when:
            1) When specifically told to do so
            2) When it is not a good idea to batch anymore
            3) When it is necessary to send batch for other reasons
               (One such reason is when READ's must be performed)

            1) is covered by exec_bulk_update calls.
            2) and 3) is handled by the bulk_update_row method.

            bulk_update_row can execute the updates including the one
            defined in the bulk_update_row or not including the row
            in the call. This is up to the handler implementation and can
            vary from call to call.

            The dup_key_found reports the number of duplicate keys found
            in those updates actually executed. It only reports those if
            the extra call with HA_EXTRA_IGNORE_DUP_KEY have been issued.
            If this hasn't been issued it returns an error code and can
            ignore this number. Thus any handler that implements batching
            for UPDATE IGNORE must also handle this extra call properly.

            If a duplicate key is found on the record included in this
            call then it should be included in the count of dup_key_found
            and error should be set to 0 (only if these errors are ignored).
          */
          DBUG_PRINT("info", ("Batched update"));
          error= table->file->ha_bulk_update_row(table->record[1],
                                                 table->record[0],
                                                 &dup_key_found);
          limit+= dup_key_found;
          updated-= dup_key_found;
        }
        else
        {
          /* Non-batched update */
          error= table->file->ha_update_row(table->record[1],
                                            table->record[0]);
        }
        if (unlikely(error == HA_ERR_RECORD_IS_THE_SAME))
        {
          error= 0;
        }
        else if (likely(!error))
        {
          if (has_vers_fields && table->versioned(VERS_TRX_ID))
            updated_sys_ver++;
          updated++;
        }

        if (unlikely(error) &&
            (!ignore || table->file->is_fatal_error(error, HA_CHECK_ALL)))
        {
          goto error;
        }
      }

      if (likely(!error) && has_vers_fields && table->versioned(VERS_TIMESTAMP))
      {
        store_record(table, record[2]);
        table->mark_columns_per_binlog_row_image();
        error= vers_insert_history_row(table);
        restore_record(table, record[2]);
        if (unlikely(error))
        {
error:
          /*
            If (ignore && error is ignorable) we don't have to
            do anything; otherwise...
          */
          myf flags= 0;

          if (table->file->is_fatal_error(error, HA_CHECK_ALL))
            flags|= ME_FATALERROR; /* Other handler errors are fatal */

          prepare_record_for_error_message(error, table);
          table->file->print_error(error,MYF(flags));
          error= 1;
          break;
        }
        updated_sys_ver++;
      }

      if (table->triggers &&
          unlikely(table->triggers->process_triggers(thd, TRG_EVENT_UPDATE,
                                                     TRG_ACTION_AFTER, TRUE)))
      {
        error= 1;
        break;
      }

      if (!--limit && using_limit)
      {
        /*
          We have reached end-of-file in most common situations where no
          batching has occurred and if batching was supposed to occur but
          no updates were made and finally when the batch execution was
          performed without error and without finding any duplicate keys.
          If the batched updates were performed with errors we need to
          check and if no error but duplicate key's found we need to
          continue since those are not counted for in limit.
        */
        if (will_batch &&
            ((error= table->file->exec_bulk_update(&dup_key_found)) ||
             dup_key_found))
        {
 	  if (error)
          {
            /* purecov: begin inspected */
            /*
              The handler should not report error of duplicate keys if they
              are ignored. This is a requirement on batching handlers.
            */
            prepare_record_for_error_message(error, table);
            table->file->print_error(error,MYF(0));
            error= 1;
            break;
            /* purecov: end */
          }
          /*
            Either an error was found and we are ignoring errors or there
            were duplicate keys found. In both cases we need to correct
            the counters and continue the loop.
          */
          limit= dup_key_found; //limit is 0 when we get here so need to +
          updated-= dup_key_found;
        }
        else
        {
	  error= -1;				// Simulate end of file
	  break;
        }
      }
    }
    /*
      Don't try unlocking the row if skip_record reported an error since in
      this case the transaction might have been rolled back already.
    */
    else if (likely(!thd->is_error()))
      table->file->unlock_row();
    else
    {
      error= 1;
      break;
    }
    thd->get_stmt_da()->inc_current_row_for_warning();
    if (unlikely(thd->is_error()))
    {
      error= 1;
      break;
    }
  }
  ANALYZE_STOP_TRACKING(&explain->command_tracker);
  table->auto_increment_field_not_null= FALSE;
  dup_key_found= 0;
  /*
    Caching the killed status to pass as the arg to query event constuctor;
    The cached value can not change whereas the killed status can
    (externally) since this point and change of the latter won't affect
    binlogging.
    It's assumed that if an error was set in combination with an effective
    killed status then the error is due to killing.
  */
  killed_status= thd->killed; // get the status of the volatile
  // simulated killing after the loop must be ineffective for binlogging
  DBUG_EXECUTE_IF("simulate_kill_bug27571",
                  {
                    thd->set_killed(KILL_QUERY);
                  };);
  error= (killed_status == NOT_KILLED)?  error : 1;

  if (likely(error) &&
      will_batch &&
      (loc_error= table->file->exec_bulk_update(&dup_key_found)))
    /*
      An error has occurred when a batched update was performed and returned
      an error indication. It cannot be an allowed duplicate key error since
      we require the batching handler to treat this as a normal behavior.

      Otherwise we simply remove the number of duplicate keys records found
      in the batched update.
    */
  {
    /* purecov: begin inspected */
    prepare_record_for_error_message(loc_error, table);
    table->file->print_error(loc_error,MYF(ME_FATALERROR));
    error= 1;
    /* purecov: end */
  }
  else
    updated-= dup_key_found;
  if (will_batch)
    table->file->end_bulk_update();

update_end:
  table->file->try_semi_consistent_read(0);

  if (!transactional_table && updated > 0)
    thd->transaction.stmt.modified_non_trans_table= TRUE;

  end_read_record(&info);
  delete select;
  select= NULL;
  THD_STAGE_INFO(thd, stage_end);
  (void) table->file->extra(HA_EXTRA_NO_IGNORE_DUP_KEY);

  /*
    Invalidate the table in the query cache if something changed.
    This must be before binlog writing and ha_autocommit_...
  */
  if (updated)
  {
    query_cache_invalidate3(thd, table_list, 1);
  }

  if (thd->transaction.stmt.modified_non_trans_table)
      thd->transaction.all.modified_non_trans_table= TRUE;
  thd->transaction.all.m_unsafe_rollback_flags|=
    (thd->transaction.stmt.m_unsafe_rollback_flags & THD_TRANS::DID_WAIT);

  /*
    error < 0 means really no error at all: we processed all rows until the
    last one without error. error > 0 means an error (e.g. unique key
    violation and no IGNORE or REPLACE). error == 0 is also an error (if
    preparing the record or invoking before triggers fails). See
    ha_autocommit_or_rollback(error>=0) and DBUG_RETURN(error>=0) below.
    Sometimes we want to binlog even if we updated no rows, in case user used
    it to be sure master and slave are in same state.
  */
  if (likely(error < 0) || thd->transaction.stmt.modified_non_trans_table)
  {
    if (WSREP_EMULATE_BINLOG(thd) || mysql_bin_log.is_open())
    {
      int errcode= 0;
      if (likely(error < 0))
        thd->clear_error();
      else
        errcode= query_error_code(thd, killed_status == NOT_KILLED);

      ScopedStatementReplication scoped_stmt_rpl(
          table->versioned(VERS_TRX_ID) ? thd : NULL);

      if (thd->binlog_query(THD::ROW_QUERY_TYPE,
                            thd->query(), thd->query_length(),
                            transactional_table, FALSE, FALSE, errcode) > 0)
      {
        error=1;				// Rollback update
      }
    }
  }
  DBUG_ASSERT(transactional_table || !updated || thd->transaction.stmt.modified_non_trans_table);
  free_underlaid_joins(thd, select_lex);
  delete file_sort;
  if (table->file->pushed_cond)
  {
    table->file->pushed_cond= 0;
    table->file->cond_pop();
  }

  /* If LAST_INSERT_ID(X) was used, report X */
  id= thd->arg_of_last_insert_id_function ?
    thd->first_successful_insert_id_in_prev_stmt : 0;

  if (likely(error < 0) && likely(!thd->lex->analyze_stmt))
  {
    char buff[MYSQL_ERRMSG_SIZE];
    if (!table->versioned(VERS_TIMESTAMP))
      my_snprintf(buff, sizeof(buff), ER_THD(thd, ER_UPDATE_INFO), (ulong) found,
                  (ulong) updated,
                  (ulong) thd->get_stmt_da()->current_statement_warn_count());
    else
      my_snprintf(buff, sizeof(buff),
                  ER_THD(thd, ER_UPDATE_INFO_WITH_SYSTEM_VERSIONING),
                  (ulong) found, (ulong) updated, (ulong) updated_sys_ver,
                  (ulong) thd->get_stmt_da()->current_statement_warn_count());
    my_ok(thd, (thd->client_capabilities & CLIENT_FOUND_ROWS) ? found : updated,
          id, buff);
    DBUG_PRINT("info",("%ld records updated", (long) updated));
  }
  thd->count_cuted_fields= CHECK_FIELD_IGNORE;		/* calc cuted fields */
  thd->abort_on_warning= 0;
  if (thd->lex->current_select->first_cond_optimization)
  {
    thd->lex->current_select->save_leaf_tables(thd);
    thd->lex->current_select->first_cond_optimization= 0;
  }
  *found_return= found;
  *updated_return= updated;

  if (unlikely(thd->lex->analyze_stmt))
    goto emit_explain_and_leave;

  DBUG_RETURN((error >= 0 || thd->is_error()) ? 1 : 0);

err:
  delete select;
  delete file_sort;
  free_underlaid_joins(thd, select_lex);
  table->file->ha_end_keyread();
  if (table->file->pushed_cond)
    table->file->cond_pop();
  thd->abort_on_warning= 0;
  DBUG_RETURN(1);

produce_explain_and_leave:
  /*
    We come here for various "degenerate" query plans: impossible WHERE,
    no-partitions-used, impossible-range, etc.
  */
  if (unlikely(!query_plan.save_explain_update_data(query_plan.mem_root, thd)))
    goto err;

emit_explain_and_leave:
  int err2= thd->lex->explain->send_explain(thd);

  delete select;
  free_underlaid_joins(thd, select_lex);
  DBUG_RETURN((err2 || thd->is_error()) ? 1 : 0);
}


bool multi_update::init(THD *thd)
{
  table_map tables_to_update= get_table_map(fields);
  List_iterator_fast<TABLE_LIST> li(*leaves);
  TABLE_LIST *tbl;
  while ((tbl =li++))
  {
    if (tbl->is_jtbm())
      continue;
    if (!(tbl->table->map & tables_to_update))
      continue;
    if (updated_leaves.push_back(tbl, thd->mem_root))
      return true;
  }
  return false;
}


void multi_update::abort_result_set()
{
  /* the error was handled or nothing deleted and no side effects return */
  if (unlikely(error_handled ||
               (!thd->transaction.stmt.modified_non_trans_table && !updated)))
    return;

  /* Something already updated so we have to invalidate cache */
  if (updated)
    query_cache_invalidate3(thd, update_tables, 1);
  /*
    If all tables that has been updated are trans safe then just do rollback.
    If not attempt to do remaining updates.
  */

  if (! trans_safe)
  {
    DBUG_ASSERT(thd->transaction.stmt.modified_non_trans_table);
    if (do_update && table_count > 1)
    {
      /* Add warning here */
      (void) do_updates();
    }
  }
  if (thd->transaction.stmt.modified_non_trans_table)
  {
    /*
      The query has to binlog because there's a modified non-transactional table
      either from the query's list or via a stored routine: bug#13270,23333
    */
    if (WSREP_EMULATE_BINLOG(thd) || mysql_bin_log.is_open())
    {
      /*
        THD::killed status might not have been set ON at time of an error
        got caught and if happens later the killed error is written
        into repl event.
      */
      int errcode= query_error_code(thd, thd->killed == NOT_KILLED);
      /* the error of binary logging is ignored */
      (void)thd->binlog_query(THD::ROW_QUERY_TYPE,
                        thd->query(), thd->query_length(),
                        transactional_tables, FALSE, FALSE, errcode);
    }
    thd->transaction.all.modified_non_trans_table= TRUE;
  }
  thd->transaction.all.m_unsafe_rollback_flags|=
    (thd->transaction.stmt.m_unsafe_rollback_flags & THD_TRANS::DID_WAIT);
  DBUG_ASSERT(trans_safe || !updated || thd->transaction.stmt.modified_non_trans_table);
}