int setup_wild(THD *thd, TABLE_LIST *tables, List<Item> &fields,
	       List<Item> *sum_func_list,
	       uint wild_num, uint *hidden_bit_fields)
{
  if (!wild_num)
    return(0);

  Item *item;
  List_iterator<Item> it(fields);
  Query_arena *arena, backup;
  DBUG_ENTER("setup_wild");

  /*
    Don't use arena if we are not in prepared statements or stored procedures
    For PS/SP we have to use arena to remember the changes
  */
  arena= thd->activate_stmt_arena_if_needed(&backup);

  thd->lex->current_select->cur_pos_in_select_list= 0;
  while (wild_num && (item= it++))
  {
    if (item->type() == Item::FIELD_ITEM &&
        ((Item_field*) item)->field_name &&
	((Item_field*) item)->field_name[0] == '*' &&
	!((Item_field*) item)->field)
    {
      uint elem= fields.elements;
      bool any_privileges= ((Item_field *) item)->any_privileges;
      Item_subselect *subsel= thd->lex->current_select->master_unit()->item;
      if (subsel &&
          subsel->substype() == Item_subselect::EXISTS_SUBS)
      {
        /*
          It is EXISTS(SELECT * ...) and we can replace * by any constant.

          Item_int do not need fix_fields() because it is basic constant.
        */
        it.replace(new (thd->mem_root) Item_int(thd, "Not_used", (longlong) 1,
                                MY_INT64_NUM_DECIMAL_DIGITS));
      }
      else if (insert_fields(thd, ((Item_field*) item)->context,
                             ((Item_field*) item)->db_name,
                             ((Item_field*) item)->table_name, &it,
                             any_privileges, hidden_bit_fields))
      {
	if (arena)
	  thd->restore_active_arena(arena, &backup);
	DBUG_RETURN(-1);
      }
      if (sum_func_list)
      {
	/*
	  sum_func_list is a list that has the fields list as a tail.
	  Because of this we have to update the element count also for this
	  list after expanding the '*' entry.
	*/
	sum_func_list->elements+= fields.elements - elem;
      }
      wild_num--;
    }
    else
      thd->lex->current_select->cur_pos_in_select_list++;
  }
  thd->lex->current_select->cur_pos_in_select_list= UNDEF_POS;
  if (arena)
  {
    /* make * substituting permanent */
    SELECT_LEX *select_lex= thd->lex->current_select;
    select_lex->with_wild= 0;
#ifdef HAVE_valgrind
    if (&select_lex->item_list != &fields)      // Avoid warning
#endif
    /*
      The assignment below is translated to memcpy() call (at least on some
      platforms). memcpy() expects that source and destination areas do not
      overlap. That problem was detected by valgrind.
    */
    if (&select_lex->item_list != &fields)
      select_lex->item_list= fields;

    thd->restore_active_arena(arena, &backup);
  }
  DBUG_RETURN(0);
}


MDEV-25766 Unused CTE lead to a crash in find_field_in_tables/find_order_in_list

Do not assume that subquery Item always present.

bool Locked_tables_list::restore_lock(THD *thd, TABLE_LIST *dst_table_list,
                                      TABLE *table, MYSQL_LOCK *lock)
{
  MYSQL_LOCK *merged_lock;
  DBUG_ENTER("restore_lock");
  DBUG_ASSERT(!strcmp(dst_table_list->table_name, table->s->table_name.str));

  /* Ensure we have the memory to add the table back */
  if (!(merged_lock= mysql_lock_merge(thd->lock, lock)))
    DBUG_RETURN(1);
  thd->lock= merged_lock;

  /* Link to the new table */
  dst_table_list->table= table;
  /*
    The lock type may have changed (normally it should not as create
    table will lock the table in write mode
  */
  dst_table_list->lock_type= table->reginfo.lock_type;
  table->pos_in_locked_tables= dst_table_list;

  add_back_last_deleted_lock(dst_table_list);

  table->mdl_ticket->downgrade_lock(table->reginfo.lock_type >=
                                    TL_WRITE_ALLOW_WRITE ?
                                    MDL_SHARED_NO_READ_WRITE :
                                    MDL_SHARED_READ);

  DBUG_RETURN(0);
}

MariaDB through 10.5.9 allows an application crash in find_field_in_tables and find_order_in_list via an unused common table expression (CTE).


void switch_to_nullable_trigger_fields(List<Item> &items, TABLE *table)
{
  Field** field= table->field_to_fill();

 /* True if we have NOT NULL fields and BEFORE triggers */
  if (field != table->field)
  {
    List_iterator_fast<Item> it(items);
    Item *item;

    while ((item= it++))
      item->walk(&Item::switch_to_nullable_fields_processor, 1, field);
    table->triggers->reset_extra_null_bitmap();
  }
}


bool MDL_deadlock_handler::handle_condition(THD *,
                                            uint sql_errno,
                                            const char*,
                                            Sql_condition::enum_warning_level*,
                                            const char*,
                                            Sql_condition ** cond_hdl)
{
  *cond_hdl= NULL;
  if (! m_is_active && sql_errno == ER_LOCK_DEADLOCK)
  {
    /* Disable the handler to avoid infinite recursion. */
    m_is_active= TRUE;
    (void) m_ot_ctx->request_backoff_action(
             Open_table_context::OT_BACKOFF_AND_RETRY,
             NULL);
    m_is_active= FALSE;
    /*
      If the above back-off request failed, a new instance of
      ER_LOCK_DEADLOCK error was emitted. Thus the current
      instance of error condition can be treated as handled.
    */
    return TRUE;
  }
  return FALSE;
}


TABLE_LIST *find_table_in_list(TABLE_LIST *table,
                               TABLE_LIST *TABLE_LIST::*link,
                               const char *db_name,
                               const char *table_name)
{
  for (; table; table= table->*link )
  {
    if (strcmp(table->db, db_name) == 0 &&
        strcmp(table->table_name, table_name) == 0)
      break;
  }
  return table;
}


bool DML_prelocking_strategy::
handle_routine(THD *thd, Query_tables_list *prelocking_ctx,
               Sroutine_hash_entry *rt, sp_head *sp, bool *need_prelocking)
{
  /*
    We assume that for any "CALL proc(...)" statement sroutines_list will
    have 'proc' as first element (it may have several, consider e.g.
    "proc(sp_func(...)))". This property is currently guaranted by the
    parser.
  */

  if (rt != (Sroutine_hash_entry*)prelocking_ctx->sroutines_list.first ||
      rt->mdl_request.key.mdl_namespace() != MDL_key::PROCEDURE)
  {
    *need_prelocking= TRUE;
    sp_update_stmt_used_routines(thd, prelocking_ctx, &sp->m_sroutines,
                                 rt->belong_to_view);
    (void)sp->add_used_tables_to_table_list(thd,
                                            &prelocking_ctx->query_tables_last,
                                            rt->belong_to_view);
  }
  sp->propagate_attributes(prelocking_ctx);
  return FALSE;
}


bool setup_fields(THD *thd, Ref_ptr_array ref_pointer_array,
                  List<Item> &fields, enum_mark_columns mark_used_columns,
                  List<Item> *sum_func_list, List<Item> *pre_fix,
                  bool allow_sum_func)
{
  Item *item;
  enum_mark_columns save_mark_used_columns= thd->mark_used_columns;
  nesting_map save_allow_sum_func= thd->lex->allow_sum_func;
  List_iterator<Item> it(fields);
  bool save_is_item_list_lookup;
  bool make_pre_fix= (pre_fix && (pre_fix->elements == 0));
  DBUG_ENTER("setup_fields");
  DBUG_PRINT("enter", ("ref_pointer_array: %p", ref_pointer_array.array()));

  thd->mark_used_columns= mark_used_columns;
  DBUG_PRINT("info", ("thd->mark_used_columns: %d", thd->mark_used_columns));
  if (allow_sum_func)
    thd->lex->allow_sum_func|=
      (nesting_map)1 << thd->lex->current_select->nest_level;
  thd->where= THD::DEFAULT_WHERE;
  save_is_item_list_lookup= thd->lex->current_select->is_item_list_lookup;
  thd->lex->current_select->is_item_list_lookup= 0;

  /*
    To prevent fail on forward lookup we fill it with zerows,
    then if we got pointer on zero after find_item_in_list we will know
    that it is forward lookup.

    There is other way to solve problem: fill array with pointers to list,
    but it will be slower.

    TODO: remove it when (if) we made one list for allfields and
    ref_pointer_array
  */
  if (!ref_pointer_array.is_null())
  {
    DBUG_ASSERT(ref_pointer_array.size() >= fields.elements);
    memset(ref_pointer_array.array(), 0, sizeof(Item *) * fields.elements);
  }

  /*
    We call set_entry() there (before fix_fields() of the whole list of field
    items) because:
    1) the list of field items has same order as in the query, and the
       Item_func_get_user_var item may go before the Item_func_set_user_var:
          SELECT @a, @a := 10 FROM t;
    2) The entry->update_query_id value controls constantness of
       Item_func_get_user_var items, so in presence of Item_func_set_user_var
       items we have to refresh their entries before fixing of
       Item_func_get_user_var items.
  */
  List_iterator<Item_func_set_user_var> li(thd->lex->set_var_list);
  Item_func_set_user_var *var;
  while ((var= li++))
    var->set_entry(thd, FALSE);

  Ref_ptr_array ref= ref_pointer_array;
  thd->lex->current_select->cur_pos_in_select_list= 0;
  while ((item= it++))
  {
    if (make_pre_fix)
      pre_fix->push_back(item, thd->stmt_arena->mem_root);

    if ((!item->fixed && item->fix_fields(thd, it.ref())) ||
	(item= *(it.ref()))->check_cols(1))
    {
      thd->lex->current_select->is_item_list_lookup= save_is_item_list_lookup;
      thd->lex->allow_sum_func= save_allow_sum_func;
      thd->mark_used_columns= save_mark_used_columns;
      DBUG_PRINT("info", ("thd->mark_used_columns: %d", thd->mark_used_columns));
      DBUG_RETURN(TRUE); /* purecov: inspected */
    }
    if (!ref.is_null())
    {
      ref[0]= item;
      ref.pop_front();
    }
    /*
      split_sum_func() must be called for Window Function items, see
      Item_window_func::split_sum_func.
    */
    if (sum_func_list &&
         ((item->with_sum_func && item->type() != Item::SUM_FUNC_ITEM) ||
          item->with_window_func))
    {
      item->split_sum_func(thd, ref_pointer_array, *sum_func_list,
                           SPLIT_SUM_SELECT);
    }
    thd->lex->current_select->select_list_tables|= item->used_tables();
    thd->lex->used_tables|= item->used_tables();
    thd->lex->current_select->cur_pos_in_select_list++;
  }
  thd->lex->current_select->is_item_list_lookup= save_is_item_list_lookup;
  thd->lex->current_select->cur_pos_in_select_list= UNDEF_POS;

  thd->lex->allow_sum_func= save_allow_sum_func;
  thd->mark_used_columns= save_mark_used_columns;
  DBUG_PRINT("info", ("thd->mark_used_columns: %d", thd->mark_used_columns));
  DBUG_RETURN(MY_TEST(thd->is_error()));
}


int init_ftfuncs(THD *thd, SELECT_LEX *select_lex, bool no_order)
{
  if (select_lex->ftfunc_list->elements)
  {
    List_iterator<Item_func_match> li(*(select_lex->ftfunc_list));
    Item_func_match *ifm;
    DBUG_PRINT("info",("Performing FULLTEXT search"));

    while ((ifm=li++))
      if (unlikely(!ifm->fixed))
        /*
          it mean that clause where was FT function was removed, so we have
          to remove the function from the list.
        */
        li.remove();
      else
        ifm->init_search(thd, no_order);
  }
  return 0;
}


void switch_defaults_to_nullable_trigger_fields(TABLE *table)
{
  if (!table->default_field)
    return; // no defaults

  Field **trigger_field= table->field_to_fill();

 /* True if we have NOT NULL fields and BEFORE triggers */
  if (trigger_field != table->field)
  {
    for (Field **field_ptr= table->default_field; *field_ptr ; field_ptr++)
    {
      Field *field= (*field_ptr);
      field->default_value->expr->walk(&Item::switch_to_nullable_fields_processor, 1, trigger_field);
      *field_ptr= (trigger_field[field->field_index]);
    }
  }
}


bool No_such_table_error_handler::safely_trapped_errors()
{
  /*
    If m_unhandled_errors != 0, something else, unanticipated, happened,
    so the error is not trapped but returned to the caller.
    Multiple ER_NO_SUCH_TABLE can be raised in case of views.
  */
  return ((m_handled_errors > 0) && (m_unhandled_errors == 0));
}


  bool safely_trapped_errors()
  {
    /*
      Check for m_handled_errors is here for extra safety.
      It can be useful in situation when call to open_table()
      fails because some error which was suppressed by another
      error handler (e.g. in case of MDL deadlock which we
      decided to solve by back-off and retry).
    */
    return (m_handled_errors && (! m_unhandled_errors));
  }


fill_record(THD *thd, TABLE *table, Field **ptr, List<Item> &values,
            bool ignore_errors, bool use_value)
{
  List_iterator_fast<Item> v(values);
  List<TABLE> tbl_list;
  Item *value;
  Field *field;
  bool abort_on_warning_saved= thd->abort_on_warning;
  uint autoinc_index= table->next_number_field
                        ? table->next_number_field->field_index
                        : ~0U;
  DBUG_ENTER("fill_record");

  if (!*ptr)
  {
    /* No fields to update, quite strange!*/
    DBUG_RETURN(0);
  }

  /*
    On INSERT or UPDATE fields are checked to be from the same table,
    thus we safely can take table from the first field.
  */
  DBUG_ASSERT((*ptr)->table == table);

  /*
    Reset the table->auto_increment_field_not_null as it is valid for
    only one row.
  */
  table->auto_increment_field_not_null= FALSE;
  while ((field = *ptr++) && ! thd->is_error())
  {
    /* Ensure that all fields are from the same table */
    DBUG_ASSERT(field->table == table);

    value=v++;
    if (field->field_index == autoinc_index)
      table->auto_increment_field_not_null= TRUE;
    if (field->vcol_info &&
        !value->vcol_assignment_allowed_value() &&
        table->s->table_category != TABLE_CATEGORY_TEMPORARY)
    {
      push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
                          ER_WARNING_NON_DEFAULT_VALUE_FOR_VIRTUAL_COLUMN,
                          ER_THD(thd, ER_WARNING_NON_DEFAULT_VALUE_FOR_VIRTUAL_COLUMN),
                          field->field_name, table->s->table_name.str);
    }

    if (use_value)
      value->save_val(field);
    else
      if (value->save_in_field(field, 0) < 0)
        goto err;
    field->set_has_explicit_value();
  }
  /* Update virtual fields */
  thd->abort_on_warning= FALSE;
  if (table->vfield &&
      table->update_virtual_fields(table->file, VCOL_UPDATE_FOR_WRITE))
    goto err;
  thd->abort_on_warning= abort_on_warning_saved;
  DBUG_RETURN(thd->is_error());

err:
  thd->abort_on_warning= abort_on_warning_saved;
  table->auto_increment_field_not_null= FALSE;
  DBUG_RETURN(TRUE);
}


void Locked_tables_list::reset()
{
  free_root(&m_locked_tables_root, MYF(0));
  m_locked_tables= NULL;
  m_locked_tables_last= &m_locked_tables;
  m_reopen_array= NULL;
  m_locked_tables_count= 0;
  some_table_marked_for_reopen= 0;
}


static bool auto_repair_table(THD *thd, TABLE_LIST *table_list)
{
  TABLE_SHARE *share;
  TABLE *entry;
  bool result= TRUE;

  thd->clear_error();

  if (!(entry= (TABLE*)my_malloc(sizeof(TABLE), MYF(MY_WME))))
    return result;

  if (!(share= tdc_acquire_share(thd, table_list, GTS_TABLE)))
    goto end_free;

  DBUG_ASSERT(! share->is_view);

  if (open_table_from_share(thd, share, table_list->alias,
                            HA_OPEN_KEYFILE | HA_TRY_READ_ONLY,
                            EXTRA_RECORD,
                            ha_open_options | HA_OPEN_FOR_REPAIR,
                            entry, FALSE) || ! entry->file ||
      (entry->file->is_crashed() && entry->file->ha_check_and_repair(thd)))
  {
    /* Give right error message */
    thd->clear_error();
    my_error(ER_NOT_KEYFILE, MYF(0), share->table_name.str);
    sql_print_error("Couldn't repair table: %s.%s", share->db.str,
                    share->table_name.str);
    if (entry->file)
      closefrm(entry);
  }
  else
  {
    thd->clear_error();			// Clear error message
    closefrm(entry);
    result= FALSE;
  }

  tdc_release_share(share);
  /* Remove the repaired share from the table cache. */
  tdc_remove_table(thd, TDC_RT_REMOVE_ALL,
                   table_list->db, table_list->table_name,
                   FALSE);
end_free:
  my_free(entry);
  return result;
}


check_and_update_routine_version(THD *thd, Sroutine_hash_entry *rt,
                                 sp_head *sp)
{
  ulong spc_version= sp_cache_version();
  /* sp is NULL if there is no such routine. */
  ulong version= sp ? sp->sp_cache_version() : spc_version;
  /*
    If the version in the parse tree is stale,
    or the version in the cache is stale and sp is not used,
    we need to reprepare.
    Sic: version != spc_version <--> sp is not NULL.
  */
  if (rt->m_sp_cache_version != version ||
      (version != spc_version && !sp->is_invoked()))
  {
    if (thd->m_reprepare_observer &&
        thd->m_reprepare_observer->report_error(thd))
    {
      /*
        Version of the sp cache is different from the
        previous execution of the prepared statement, and it is
        unacceptable for this SQLCOM. Error has been reported.
      */
      DBUG_ASSERT(thd->is_error());
      return TRUE;
    }
    /* Always maintain the latest cache version. */
    rt->m_sp_cache_version= version;
  }
  return FALSE;
}


my_bool mysql_rm_tmp_tables(void)
{
  uint i, idx;
  char	filePath[FN_REFLEN], *tmpdir, filePathCopy[FN_REFLEN];
  MY_DIR *dirp;
  FILEINFO *file;
  TABLE_SHARE share;
  THD *thd;
  DBUG_ENTER("mysql_rm_tmp_tables");

  if (!(thd= new THD(0)))
    DBUG_RETURN(1);
  thd->thread_stack= (char*) &thd;
  thd->store_globals();

  for (i=0; i<=mysql_tmpdir_list.max; i++)
  {
    tmpdir=mysql_tmpdir_list.list[i];
    /* See if the directory exists */
    if (!(dirp = my_dir(tmpdir,MYF(MY_WME | MY_DONT_SORT))))
      continue;

    /* Remove all SQLxxx tables from directory */

    for (idx=0 ; idx < (uint) dirp->number_of_files ; idx++)
    {
      file=dirp->dir_entry+idx;

      if (!strncmp(file->name, tmp_file_prefix, tmp_file_prefix_length))
      {
        char *ext= fn_ext(file->name);
        uint ext_len= strlen(ext);
        uint filePath_len= my_snprintf(filePath, sizeof(filePath),
                                       "%s%c%s", tmpdir, FN_LIBCHAR,
                                       file->name);
        if (!strcmp(reg_ext, ext))
        {
          handler *handler_file= 0;
          /* We should cut file extention before deleting of table */
          memcpy(filePathCopy, filePath, filePath_len - ext_len);
          filePathCopy[filePath_len - ext_len]= 0;
          init_tmp_table_share(thd, &share, "", 0, "", filePathCopy);
          if (!open_table_def(thd, &share) &&
              ((handler_file= get_new_handler(&share, thd->mem_root,
                                              share.db_type()))))
          {
            handler_file->ha_delete_table(filePathCopy);
            delete handler_file;
          }
          free_table_share(&share);
        }
        /*
          File can be already deleted by tmp_table.file->delete_table().
          So we hide error messages which happnes during deleting of these
          files(MYF(0)).
        */
        (void) mysql_file_delete(key_file_misc, filePath, MYF(0));
      }
    }
    my_dirend(dirp);
  }
  delete thd;
  DBUG_RETURN(0);
}


void Locked_tables_list::mark_table_for_reopen(THD *thd, TABLE *table)
{
  TABLE_SHARE *share= table->s;

    for (TABLE_LIST *table_list= m_locked_tables;
       table_list; table_list= table_list->next_global)
  {
    if (table_list->table->s == share)
      table_list->table->internal_set_needs_reopen(true);
  }
  /* This is needed in the case where lock tables where not used */
  table->internal_set_needs_reopen(true);
  some_table_marked_for_reopen= 1;
}


test_if_string_in_list(const char *find, List<String> *str_list)
{
  List_iterator<String> str_list_it(*str_list);
  String *curr_str;
  size_t find_length= strlen(find);
  while ((curr_str= str_list_it++))
  {
    if (find_length != curr_str->length())
      continue;
    if (!my_strcasecmp(system_charset_info, find, curr_str->ptr()))
      return TRUE;
  }
  return FALSE;
}


bool Alter_table_prelocking_strategy::
handle_table(THD *thd, Query_tables_list *prelocking_ctx,
             TABLE_LIST *table_list, bool *need_prelocking)
{
  return FALSE;
}


static my_bool close_cached_tables_callback(TDC_element *element,
                                            close_cached_tables_arg *arg)
{
  mysql_mutex_lock(&element->LOCK_table_share);
  if (element->share && element->flushed &&
      element->version < arg->refresh_version)
  {
    /* wait_for_old_version() will unlock mutex and free share */
    arg->element= element;
    return TRUE;
  }
  mysql_mutex_unlock(&element->LOCK_table_share);
  return FALSE;
}


open_tables_check_upgradable_mdl(THD *thd, TABLE_LIST *tables_start,
                                 TABLE_LIST *tables_end, uint flags)
{
  TABLE_LIST *table;

  DBUG_ASSERT(thd->locked_tables_mode);

  for (table= tables_start; table && table != tables_end;
       table= table->next_global)
  {
    /*
      Check below needs to be updated if this function starts
      called for SRO locks.
    */
    DBUG_ASSERT(table->mdl_request.type != MDL_SHARED_READ_ONLY);
    if (table->mdl_request.type < MDL_SHARED_UPGRADABLE ||
        table->open_type == OT_TEMPORARY_ONLY ||
        (table->open_type == OT_TEMPORARY_OR_BASE && is_temporary_table(table)))
    {
      continue;
    }

    /*
      We don't need to do anything about the found TABLE instance as it
      will be handled later in open_tables(), we only need to check that
      an upgradable lock is already acquired. When we enter LOCK TABLES
      mode, SNRW locks are acquired before all other locks. So if under
      LOCK TABLES we find that there is TABLE instance with upgradeable
      lock, all other instances of TABLE for the same table will have the
      same ticket.

      Note that this works OK even for CREATE TABLE statements which
      request X type of metadata lock. This is because under LOCK TABLES
      such statements don't create the table but only check if it exists
      or, in most complex case, only insert into it.
      Thus SNRW lock should be enough.

      Note that find_table_for_mdl_upgrade() will report an error if
      no suitable ticket is found.
    */
    if (!find_table_for_mdl_upgrade(thd, table->db, table->table_name, NULL))
      return TRUE;
  }

  return FALSE;
}


int dynamic_column_error_message(enum_dyncol_func_result rc)
{
  switch (rc) {
  case ER_DYNCOL_YES:
  case ER_DYNCOL_OK:
  case ER_DYNCOL_TRUNCATED:
    break; // it is not an error
  case ER_DYNCOL_FORMAT:
    my_error(ER_DYN_COL_WRONG_FORMAT, MYF(0));
    break;
  case ER_DYNCOL_LIMIT:
    my_error(ER_DYN_COL_IMPLEMENTATION_LIMIT, MYF(0));
    break;
  case ER_DYNCOL_RESOURCE:
    my_error(ER_OUT_OF_RESOURCES, MYF(0));
    break;
  case ER_DYNCOL_DATA:
    my_error(ER_DYN_COL_DATA, MYF(0));
    break;
  case ER_DYNCOL_UNKNOWN_CHARSET:
    my_error(ER_DYN_COL_WRONG_CHARSET, MYF(0));
    break;
  }
  return rc;
}


static my_bool list_open_tables_callback(TDC_element *element,
                                         list_open_tables_arg *arg)
{
  char *db= (char*) element->m_key;
  char *table_name= (char*) element->m_key + strlen((char*) element->m_key) + 1;

  if (arg->db && my_strcasecmp(system_charset_info, arg->db, db))
    return FALSE;
  if (arg->wild && wild_compare(table_name, arg->wild, 0))
    return FALSE;

  /* Check if user has SELECT privilege for any column in the table */
  arg->table_list.db= db;
  arg->table_list.table_name= table_name;
  arg->table_list.grant.privilege= 0;

  if (check_table_access(arg->thd, SELECT_ACL, &arg->table_list, TRUE, 1, TRUE))
    return FALSE;

  if (!(*arg->start_list= (OPEN_TABLE_LIST *) arg->thd->alloc(
                    sizeof(**arg->start_list) + element->m_key_length)))
    return TRUE;

  strmov((*arg->start_list)->table=
         strmov(((*arg->start_list)->db= (char*) ((*arg->start_list) + 1)),
                db) + 1, table_name);
  (*arg->start_list)->in_use= 0;

  mysql_mutex_lock(&element->LOCK_table_share);
  All_share_tables_list::Iterator it(element->all_tables);
  TABLE *table;
  while ((table= it++))
    if (table->in_use)
      ++(*arg->start_list)->in_use;
  mysql_mutex_unlock(&element->LOCK_table_share);
  (*arg->start_list)->locked= 0;                   /* Obsolete. */
  arg->start_list= &(*arg->start_list)->next;
  *arg->start_list= 0;
  return FALSE;
}


bool table_already_fk_prelocked(TABLE_LIST *tl, LEX_STRING *db,
                                LEX_STRING *table, thr_lock_type lock_type)
{
  for (; tl; tl= tl->next_global )
  {
    if (tl->lock_type >= lock_type &&
        tl->prelocking_placeholder == TABLE_LIST::FK &&
        strcmp(tl->db, db->str) == 0 &&
        strcmp(tl->table_name, table->str) == 0)
      return true;
  }
  return false;
}


fill_record_n_invoke_before_triggers(THD *thd, TABLE *table, Field **ptr,
                                     List<Item> &values, bool ignore_errors,
                                     enum trg_event_type event)
{
  bool result;
  Table_triggers_list *triggers= table->triggers;

  result= fill_record(thd, table, ptr, values, ignore_errors, FALSE);

  if (!result && triggers && *ptr)
    result= triggers->process_triggers(thd, event, TRG_ACTION_BEFORE, TRUE) ||
            not_null_fields_have_null_values(table);
  /*
    Re-calculate virtual fields to cater for cases when base columns are
    updated by the triggers.
  */
  if (!result && triggers && *ptr)
  {
    DBUG_ASSERT(table == (*ptr)->table);
    if (table->vfield)
      result= table->update_virtual_fields(table->file, VCOL_UPDATE_FOR_WRITE);
  }
  return result;

}


open_system_table_for_update(THD *thd, TABLE_LIST *one_table)
{
  DBUG_ENTER("open_system_table_for_update");

  TABLE *table= open_ltable(thd, one_table, one_table->lock_type,
                            MYSQL_LOCK_IGNORE_TIMEOUT);
  if (table)
  {
    DBUG_ASSERT(table->s->table_category == TABLE_CATEGORY_SYSTEM);
    table->use_all_columns();
  }

  DBUG_RETURN(table);
}


Locked_tables_list::unlock_locked_table(THD *thd, MDL_ticket *mdl_ticket)
{
  /*
    Ensure we are in locked table mode.
    As this function is only called on error condition it's better
    to check this condition here than in the caller.
  */
  if (thd->locked_tables_mode != LTM_LOCK_TABLES)
    return;

  if (mdl_ticket)
  {
    /*
      Under LOCK TABLES we may have several instances of table open
      and locked and therefore have to remove several metadata lock
      requests associated with them.
    */
    thd->mdl_context.release_all_locks_for_name(mdl_ticket);
  }

  if (thd->lock->table_count == 0)
    unlock_locked_tables(thd);
}


fill_record_n_invoke_before_triggers(THD *thd, TABLE *table,
                                     List<Item> &fields,
                                     List<Item> &values, bool ignore_errors,
                                     enum trg_event_type event)
{
  bool result;
  Table_triggers_list *triggers= table->triggers;

  result= fill_record(thd, table, fields, values, ignore_errors,
                      event == TRG_EVENT_UPDATE);

  if (!result && triggers)
  {
    if (triggers->process_triggers(thd, event, TRG_ACTION_BEFORE,
                                    TRUE) ||
        not_null_fields_have_null_values(table))
      return TRUE;

    /*
      Re-calculate virtual fields to cater for cases when base columns are
      updated by the triggers.
    */
    if (table->vfield && fields.elements)
    {
      Item *fld= (Item_field*) fields.head();
      Item_field *item_field= fld->field_for_view_update();
      if (item_field)
      {
        DBUG_ASSERT(table == item_field->field->table);
        result|= table->update_virtual_fields(table->file,
                                              VCOL_UPDATE_FOR_WRITE);
      }
    }
  }
  return result;
}


TABLE *find_table_for_mdl_upgrade(THD *thd, const char *db,
                                  const char *table_name, int *p_error)
{
  TABLE *tab= find_locked_table(thd->open_tables, db, table_name);
  int error;

  if (!tab)
  {
    error= ER_TABLE_NOT_LOCKED;
    goto err_exit;
  }

  /*
    It is not safe to upgrade the metadata lock without a global IX lock.
    This can happen with FLUSH TABLES <list> WITH READ LOCK as we in these
    cases don't take a global IX lock in order to be compatible with
    global read lock.
  */
  if (!thd->mdl_context.is_lock_owner(MDL_key::GLOBAL, "", "",
                                      MDL_INTENTION_EXCLUSIVE))
  {
    error= ER_TABLE_NOT_LOCKED_FOR_WRITE;
    goto err_exit;
  }

  while (tab->mdl_ticket != NULL &&
         !tab->mdl_ticket->is_upgradable_or_exclusive() &&
         (tab= find_locked_table(tab->next, db, table_name)))
    continue;

  if (unlikely(!tab))
  {
    error= ER_TABLE_NOT_LOCKED_FOR_WRITE;
    goto err_exit;
  }

  return tab;

err_exit:
  if (p_error)
    *p_error= error;
  else
    my_error(error, MYF(0), table_name);

  return NULL;
}


void wrap_ident(THD *thd, Item **conds)
{
  Item_direct_ref_to_ident *wrapper;
  DBUG_ASSERT((*conds)->type() == Item::FIELD_ITEM || (*conds)->type() == Item::REF_ITEM);
  Query_arena *arena, backup;
  arena= thd->activate_stmt_arena_if_needed(&backup);
  if ((wrapper= new (thd->mem_root) Item_direct_ref_to_ident(thd, (Item_ident *) (*conds))))
    (*conds)= (Item*) wrapper;
  if (arena)
    thd->restore_active_arena(arena, &backup);
}


void Locked_tables_list::add_back_last_deleted_lock(TABLE_LIST *dst_table_list)
{
  /* Link the lock back in the locked tables list */
  dst_table_list->prev_global= m_locked_tables_last;
  *m_locked_tables_last= dst_table_list;
  m_locked_tables_last= &dst_table_list->next_global;
  dst_table_list->next_global= 0;
  m_locked_tables_count++;
}


open_table_get_mdl_lock(THD *thd, Open_table_context *ot_ctx,
                        MDL_request *mdl_request,
                        uint flags,
                        MDL_ticket **mdl_ticket)
{
  MDL_request mdl_request_shared;

  if (flags & (MYSQL_OPEN_FORCE_SHARED_MDL |
               MYSQL_OPEN_FORCE_SHARED_HIGH_PRIO_MDL))
  {
    /*
      MYSQL_OPEN_FORCE_SHARED_MDL flag means that we are executing
      PREPARE for a prepared statement and want to override
      the type-of-operation aware metadata lock which was set
      in the parser/during view opening with a simple shared
      metadata lock.
      This is necessary to allow concurrent execution of PREPARE
      and LOCK TABLES WRITE statement against the same table.

      MYSQL_OPEN_FORCE_SHARED_HIGH_PRIO_MDL flag means that we open
      the table in order to get information about it for one of I_S
      queries and also want to override the type-of-operation aware
      shared metadata lock which was set earlier (e.g. during view
      opening) with a high-priority shared metadata lock.
      This is necessary to avoid unnecessary waiting and extra
      ER_WARN_I_S_SKIPPED_TABLE warnings when accessing I_S tables.

      These two flags are mutually exclusive.
    */
    DBUG_ASSERT(!(flags & MYSQL_OPEN_FORCE_SHARED_MDL) ||
                !(flags & MYSQL_OPEN_FORCE_SHARED_HIGH_PRIO_MDL));

    mdl_request_shared.init(&mdl_request->key,
                            (flags & MYSQL_OPEN_FORCE_SHARED_MDL) ?
                            MDL_SHARED : MDL_SHARED_HIGH_PRIO,
                            MDL_TRANSACTION);
    mdl_request= &mdl_request_shared;
  }

  if (flags & MYSQL_OPEN_FAIL_ON_MDL_CONFLICT)
  {
    /*
      When table is being open in order to get data for I_S table,
      we might have some tables not only open but also locked (e.g. when
      this happens under LOCK TABLES or in a stored function).
      As a result by waiting on a conflicting metadata lock to go away
      we may create a deadlock which won't entirely belong to the
      MDL subsystem and thus won't be detectable by this subsystem's
      deadlock detector.
      To avoid such situation we skip the trouble-making table if
      there is a conflicting lock.
    */
    if (thd->mdl_context.try_acquire_lock(mdl_request))
      return TRUE;
    if (mdl_request->ticket == NULL)
    {
      my_error(ER_WARN_I_S_SKIPPED_TABLE, MYF(0),
               mdl_request->key.db_name(), mdl_request->key.name());
      return TRUE;
    }
  }
  else
  {
    /*
      We are doing a normal table open. Let us try to acquire a metadata
      lock on the table. If there is a conflicting lock, acquire_lock()
      will wait for it to go away. Sometimes this waiting may lead to a
      deadlock, with the following results:
      1) If a deadlock is entirely within MDL subsystem, it is
         detected by the deadlock detector of this subsystem.
         ER_LOCK_DEADLOCK error is produced. Then, the error handler
         that is installed prior to the call to acquire_lock() attempts
         to request a back-off and retry. Upon success, ER_LOCK_DEADLOCK
         error is suppressed, otherwise propagated up the calling stack.
      2) Otherwise, a deadlock may occur when the wait-for graph
         includes edges not visible to the MDL deadlock detector.
         One such example is a wait on an InnoDB row lock, e.g. when:
         conn C1 gets SR MDL lock on t1 with SELECT * FROM t1
         conn C2 gets a row lock on t2 with  SELECT * FROM t2 FOR UPDATE
         conn C3 gets in and waits on C1 with DROP TABLE t0, t1
         conn C2 continues and blocks on C3 with SELECT * FROM t0
         conn C1 deadlocks by waiting on C2 by issuing SELECT * FROM
         t2 LOCK IN SHARE MODE.
         Such circular waits are currently only resolved by timeouts,
         e.g. @@innodb_lock_wait_timeout or @@lock_wait_timeout.
    */
    MDL_deadlock_handler mdl_deadlock_handler(ot_ctx);

    thd->push_internal_handler(&mdl_deadlock_handler);
    bool result= thd->mdl_context.acquire_lock(mdl_request,
                                               ot_ctx->get_timeout());
    thd->pop_internal_handler();

    if (result && !ot_ctx->can_recover_from_failed_open())
      return TRUE;
  }
  *mdl_ticket= mdl_request->ticket;
  return FALSE;
}


uint get_table_def_key(const TABLE_LIST *table_list, const char **key)
{
  /*
    This call relies on the fact that TABLE_LIST::mdl_request::key object
    is properly initialized, so table definition cache can be produced
    from key used by MDL subsystem.
  */
  DBUG_ASSERT(!strcmp(table_list->get_db_name(),
                      table_list->mdl_request.key.db_name()) &&
              !strcmp(table_list->get_table_name(),
                      table_list->mdl_request.key.name()));

  *key= (const char*)table_list->mdl_request.key.ptr() + 1;
  return table_list->mdl_request.key.length() - 1;
}


TABLE *open_n_lock_single_table(THD *thd, TABLE_LIST *table_l,
                                thr_lock_type lock_type, uint flags,
                                Prelocking_strategy *prelocking_strategy)
{
  TABLE_LIST *save_next_global;
  DBUG_ENTER("open_n_lock_single_table");

  /* Remember old 'next' pointer. */
  save_next_global= table_l->next_global;
  /* Break list. */
  table_l->next_global= NULL;

  /* Set requested lock type. */
  table_l->lock_type= lock_type;
  /* Allow to open real tables only. */
  table_l->required_type= FRMTYPE_TABLE;

  /* Open the table. */
  if (open_and_lock_tables(thd, table_l, FALSE, flags,
                           prelocking_strategy))
    table_l->table= NULL; /* Just to be sure. */

  /* Restore list. */
  table_l->next_global= save_next_global;

  DBUG_RETURN(table_l->table);
}


No_such_table_error_handler::handle_condition(THD *,
                                              uint sql_errno,
                                              const char*,
                                              Sql_condition::enum_warning_level *level,
                                              const char*,
                                              Sql_condition ** cond_hdl)
{
  *cond_hdl= NULL;
  if (sql_errno == ER_NO_SUCH_TABLE || sql_errno == ER_NO_SUCH_TABLE_IN_ENGINE)
  {
    m_handled_errors++;
    return TRUE;
  }

  if (*level == Sql_condition::WARN_LEVEL_ERROR)
    m_unhandled_errors++;
  return FALSE;
}


close_mysql_tables(THD *thd)
{
  if (! thd->in_sub_stmt)
    trans_commit_stmt(thd);
  close_thread_tables(thd);
  thd->release_transactional_locks();
}


close_system_tables(THD *thd, Open_tables_backup *backup)
{
  close_thread_tables(thd);
  thd->restore_backup_open_tables_state(backup);
}


Locked_tables_list::reopen_tables(THD *thd, bool need_reopen)
{
  Open_table_context ot_ctx(thd, MYSQL_OPEN_REOPEN);
  size_t reopen_count= 0;
  MYSQL_LOCK *lock;
  MYSQL_LOCK *merged_lock;
  DBUG_ENTER("Locked_tables_list::reopen_tables");

  DBUG_ASSERT(some_table_marked_for_reopen || !need_reopen);

  /* Reset flag that some table was marked for reopen */
  some_table_marked_for_reopen= 0;

  for (TABLE_LIST *table_list= m_locked_tables;
       table_list; table_list= table_list->next_global)
  {
    if (need_reopen)
    {
      if (!table_list->table || !table_list->table->needs_reopen())
        continue;
      for (TABLE **prev= &thd->open_tables; *prev; prev= &(*prev)->next)
      {
        if (*prev == table_list->table)
        {
          thd->locked_tables_list.unlink_from_list(thd, table_list, false);
          mysql_lock_remove(thd, thd->lock, *prev);
          (*prev)->file->extra(HA_EXTRA_PREPARE_FOR_FORCED_CLOSE);
          close_thread_table(thd, prev);
          break;
        }
      }
      DBUG_ASSERT(table_list->table == NULL);
    }
    else
    {
      if (table_list->table)                      /* The table was not closed */
        continue;
    }

    DBUG_ASSERT(reopen_count < m_locked_tables_count);
    m_reopen_array[reopen_count++]= table_list;
  }
  if (reopen_count)
  {
    TABLE **tables= (TABLE**) my_alloca(reopen_count * sizeof(TABLE*));

    for (uint i= 0 ; i < reopen_count ; i++)
    {
      TABLE_LIST *table_list= m_reopen_array[i];
      /* Links into thd->open_tables upon success */
      if (open_table(thd, table_list, &ot_ctx))
      {
        unlink_all_closed_tables(thd, 0, i);
        my_afree((void*) tables);
        DBUG_RETURN(TRUE);
      }
      tables[i]= table_list->table;
      table_list->table->pos_in_locked_tables= table_list;
      /* See also the comment on lock type in init_locked_tables(). */
      table_list->table->reginfo.lock_type= table_list->lock_type;
    }

    thd->in_lock_tables= 1;
    /*
      We re-lock all tables with mysql_lock_tables() at once rather
      than locking one table at a time because of the case
      reported in Bug#45035: when the same table is present
      in the list many times, thr_lock.c fails to grant READ lock
      on a table that is already locked by WRITE lock, even if
      WRITE lock is taken by the same thread. If READ and WRITE
      lock are passed to thr_lock.c in the same list, everything
      works fine. Patching legacy code of thr_lock.c is risking to
      break something else.
    */
    lock= mysql_lock_tables(thd, tables, reopen_count,
                            MYSQL_OPEN_REOPEN);
    thd->in_lock_tables= 0;
    if (lock == NULL || (merged_lock=
                         mysql_lock_merge(thd->lock, lock)) == NULL)
    {
      unlink_all_closed_tables(thd, lock, reopen_count);
      if (! thd->killed)
        my_error(ER_LOCK_DEADLOCK, MYF(0));
      my_afree((void*) tables);
      DBUG_RETURN(TRUE);
    }
    thd->lock= merged_lock;
    my_afree((void*) tables);
  }
  DBUG_RETURN(FALSE);
}


bool wait_while_table_is_used(THD *thd, TABLE *table,
                              enum ha_extra_function function)
{
  DBUG_ENTER("wait_while_table_is_used");
  DBUG_ASSERT(!table->s->tmp_table);
  DBUG_PRINT("enter", ("table: '%s'  share: %p  db_stat: %u  version: %lld",
                       table->s->table_name.str, table->s,
                       table->db_stat, table->s->tdc->version));

  if (thd->mdl_context.upgrade_shared_lock(
             table->mdl_ticket, MDL_EXCLUSIVE,
             thd->variables.lock_wait_timeout))
    DBUG_RETURN(TRUE);

  tdc_remove_table(thd, TDC_RT_REMOVE_NOT_OWN,
                   table->s->db.str, table->s->table_name.str,
                   FALSE);
  /* extra() call must come only after all instances above are closed */
  if (function != HA_EXTRA_NOT_USED)
    DBUG_RETURN(table->file->extra(function));
  DBUG_RETURN(FALSE);
}


bool open_normal_and_derived_tables(THD *thd, TABLE_LIST *tables, uint flags,
                                    uint dt_phases)
{
  DML_prelocking_strategy prelocking_strategy;
  uint counter;
  MDL_savepoint mdl_savepoint= thd->mdl_context.mdl_savepoint();
  DBUG_ENTER("open_normal_and_derived_tables");
  if (open_tables(thd, &tables, &counter, flags, &prelocking_strategy) ||
      mysql_handle_derived(thd->lex, dt_phases))
    goto end;

  DBUG_RETURN(0);
end:
  /*
    No need to commit/rollback the statement transaction: it's
    either not started or we're filling in an INFORMATION_SCHEMA
    table on the fly, and thus mustn't manipulate with the
    transaction of the enclosing statement.
  */
  DBUG_ASSERT(thd->transaction.stmt.is_empty() ||
              (thd->state_flags & Open_tables_state::BACKUPS_AVAIL));
  close_thread_tables(thd);
  /* Don't keep locks for a failed statement. */
  thd->mdl_context.rollback_to_savepoint(mdl_savepoint);

  DBUG_RETURN(TRUE); /* purecov: inspected */
}


close_all_tables_for_name(THD *thd, TABLE_SHARE *share,
                          ha_extra_function extra,
                          TABLE *skip_table)
{
  DBUG_ASSERT(!share->tmp_table);

  char key[MAX_DBKEY_LENGTH];
  uint key_length= share->table_cache_key.length;
  const char *db= key;
  const char *table_name= db + share->db.length + 1;
  bool remove_from_locked_tables= extra != HA_EXTRA_NOT_USED;

  memcpy(key, share->table_cache_key.str, key_length);

  for (TABLE **prev= &thd->open_tables; *prev; )
  {
    TABLE *table= *prev;

    if (table->s->table_cache_key.length == key_length &&
        !memcmp(table->s->table_cache_key.str, key, key_length) &&
        table != skip_table)
    {
      thd->locked_tables_list.unlink_from_list(thd,
                                               table->pos_in_locked_tables,
                                               remove_from_locked_tables);
      /* Inform handler that there is a drop table or a rename going on */
      if (extra != HA_EXTRA_NOT_USED && table->db_stat)
      {
        table->file->extra(extra);
        extra= HA_EXTRA_NOT_USED;               // Call extra once!
      }

      /*
        Does nothing if the table is not locked.
        This allows one to use this function after a table
        has been unlocked, e.g. in partition management.
      */
      mysql_lock_remove(thd, thd->lock, table);
      close_thread_table(thd, prev);
    }
    else
    {
      /* Step to next entry in open_tables list. */
      prev= &table->next;
    }
  }
  if (skip_table == NULL)
  {
    /* Remove the table share from the cache. */
    tdc_remove_table(thd, TDC_RT_REMOVE_ALL, db, table_name,
                     FALSE);
  }
}


TABLE *open_ltable(THD *thd, TABLE_LIST *table_list, thr_lock_type lock_type,
                   uint lock_flags)
{
  TABLE *table;
  Open_table_context ot_ctx(thd, lock_flags);
  bool error;
  DBUG_ENTER("open_ltable");

  /* Ignore temporary tables as they have already been opened. */
  if (table_list->table)
    DBUG_RETURN(table_list->table);

  /* should not be used in a prelocked_mode context, see NOTE above */
  DBUG_ASSERT(thd->locked_tables_mode < LTM_PRELOCKED);

  THD_STAGE_INFO(thd, stage_opening_tables);
  thd->current_tablenr= 0;
  /* open_ltable can be used only for BASIC TABLEs */
  table_list->required_type= FRMTYPE_TABLE;

  /* This function can't properly handle requests for such metadata locks. */
  DBUG_ASSERT(table_list->mdl_request.type < MDL_SHARED_UPGRADABLE);

  while ((error= open_table(thd, table_list, &ot_ctx)) &&
         ot_ctx.can_recover_from_failed_open())
  {
    /*
      Even though we have failed to open table we still need to
      call release_transactional_locks() to release metadata locks which
      might have been acquired successfully.
    */
    thd->mdl_context.rollback_to_savepoint(ot_ctx.start_of_statement_svp());
    table_list->mdl_request.ticket= 0;
    if (ot_ctx.recover_from_failed_open())
      break;
  }

  if (!error)
  {
    /*
      We can't have a view or some special "open_strategy" in this function
      so there should be a TABLE instance.
    */
    DBUG_ASSERT(table_list->table);
    table= table_list->table;
    if (table->file->ht->db_type == DB_TYPE_MRG_MYISAM)
    {
      /* A MERGE table must not come here. */
      /* purecov: begin tested */
      my_error(ER_WRONG_OBJECT, MYF(0), table->s->db.str,
               table->s->table_name.str, "BASE TABLE");
      table= 0;
      goto end;
      /* purecov: end */
    }

    table_list->lock_type= lock_type;
    table->grant= table_list->grant;
    if (thd->locked_tables_mode)
    {
      if (check_lock_and_start_stmt(thd, thd->lex, table_list))
	table= 0;
    }
    else
    {
      DBUG_ASSERT(thd->lock == 0);	// You must lock everything at once
      if ((table->reginfo.lock_type= lock_type) != TL_UNLOCK)
	if (! (thd->lock= mysql_lock_tables(thd, &table_list->table, 1,
                                            lock_flags)))
        {
          table= 0;
        }
    }
  }
  else
    table= 0;

end:
  if (table == NULL)
  {
    if (!thd->in_sub_stmt)
      trans_rollback_stmt(thd);
    close_thread_tables(thd);
  }
  THD_STAGE_INFO(thd, stage_after_opening_tables);

  thd_proc_info(thd, 0);
  DBUG_RETURN(table);
}


bool open_and_lock_tables(THD *thd, const DDL_options_st &options,
                          TABLE_LIST *tables,
                          bool derived, uint flags,
                          Prelocking_strategy *prelocking_strategy)
{
  uint counter;
  MDL_savepoint mdl_savepoint= thd->mdl_context.mdl_savepoint();
  DBUG_ENTER("open_and_lock_tables");
  DBUG_PRINT("enter", ("derived handling: %d", derived));

  if (open_tables(thd, options, &tables, &counter, flags, prelocking_strategy))
    goto err;

  DBUG_EXECUTE_IF("sleep_open_and_lock_after_open", {
                  const char *old_proc_info= thd->proc_info;
                  thd->proc_info= "DBUG sleep";
                  my_sleep(6000000);
                  thd->proc_info= old_proc_info;});

  if (lock_tables(thd, tables, counter, flags))
    goto err;

  (void) read_statistics_for_tables_if_needed(thd, tables);

  if (derived)
  {
    if (mysql_handle_derived(thd->lex, DT_INIT))
      goto err;
    if (thd->prepare_derived_at_open &&
        (mysql_handle_derived(thd->lex, DT_PREPARE)))
      goto err;
  }

  DBUG_RETURN(FALSE);
err:
  if (! thd->in_sub_stmt)
    trans_rollback_stmt(thd);  /* Necessary if derived handling failed. */
  close_thread_tables(thd);
  /* Don't keep locks for a failed statement. */
  thd->mdl_context.rollback_to_savepoint(mdl_savepoint);
  DBUG_RETURN(TRUE);
}


bool setup_tables_and_check_access(THD *thd, Name_resolution_context *context,
                                   List<TABLE_LIST> *from_clause,
                                   TABLE_LIST *tables, List<TABLE_LIST> &leaves,
                                   bool select_insert, ulong want_access_first,
                                   ulong want_access, bool full_table_list)
{
  DBUG_ENTER("setup_tables_and_check_access");

  if (setup_tables(thd, context, from_clause, tables,
                   leaves, select_insert, full_table_list))
    DBUG_RETURN(TRUE);

  List_iterator<TABLE_LIST> ti(leaves);
  TABLE_LIST *table_list;
  ulong access= want_access_first;
  while ((table_list= ti++))
  {
    if (table_list->belong_to_view && !table_list->view &&
        check_single_table_access(thd, access, table_list, FALSE))
    {
      tables->hide_view_error(thd);
      DBUG_RETURN(TRUE);
    }
    access= want_access;
  }
  DBUG_RETURN(FALSE);
}


bool Alter_table_prelocking_strategy::
handle_view(THD *thd, Query_tables_list *prelocking_ctx,
            TABLE_LIST *table_list, bool *need_prelocking)
{
  return FALSE;
}


open_system_tables_for_read(THD *thd, TABLE_LIST *table_list,
                            Open_tables_backup *backup)
{
  Query_tables_list query_tables_list_backup;
  LEX *lex= thd->lex;

  DBUG_ENTER("open_system_tables_for_read");

  /*
    Besides using new Open_tables_state for opening system tables,
    we also have to backup and reset/and then restore part of LEX
    which is accessed by open_tables() in order to determine if
    prelocking is needed and what tables should be added for it.
    close_system_tables() doesn't require such treatment.
  */
  lex->reset_n_backup_query_tables_list(&query_tables_list_backup);
  thd->reset_n_backup_open_tables_state(backup);
  thd->lex->sql_command= SQLCOM_SELECT;

  if (open_and_lock_tables(thd, table_list, FALSE,
                           MYSQL_OPEN_IGNORE_FLUSH |
                           MYSQL_LOCK_IGNORE_TIMEOUT))
  {
    lex->restore_backup_query_tables_list(&query_tables_list_backup);
    thd->restore_backup_open_tables_state(backup);
    DBUG_RETURN(TRUE);
  }

  for (TABLE_LIST *tables= table_list; tables; tables= tables->next_global)
  {
    DBUG_ASSERT(tables->table->s->table_category == TABLE_CATEGORY_SYSTEM);
    tables->table->use_all_columns();
  }
  lex->restore_backup_query_tables_list(&query_tables_list_backup);

  DBUG_RETURN(FALSE);
}


bool close_cached_connection_tables(THD *thd, LEX_STRING *connection)
{
  close_cached_connection_tables_arg argument;
  DBUG_ENTER("close_cached_connections");
  DBUG_ASSERT(thd);

  argument.thd= thd;
  argument.connection= connection;
  argument.tables= NULL;

  if (tdc_iterate(thd,
                  (my_hash_walk_action) close_cached_connection_tables_callback,
                  &argument))
    DBUG_RETURN(true);

  DBUG_RETURN(argument.tables ?
              close_cached_tables(thd, argument.tables, FALSE, LONG_TIMEOUT) :
              false);
}


open_log_table(THD *thd, TABLE_LIST *one_table, Open_tables_backup *backup)
{
  uint flags= ( MYSQL_OPEN_IGNORE_GLOBAL_READ_LOCK |
                MYSQL_LOCK_IGNORE_GLOBAL_READ_ONLY |
                MYSQL_OPEN_IGNORE_FLUSH |
                MYSQL_LOCK_IGNORE_TIMEOUT |
                MYSQL_LOCK_LOG_TABLE);
  TABLE *table;
  /* Save value that is changed in mysql_lock_tables() */
  ulonglong save_utime_after_lock= thd->utime_after_lock;
  DBUG_ENTER("open_log_table");

  thd->reset_n_backup_open_tables_state(backup);

  if ((table= open_ltable(thd, one_table, one_table->lock_type, flags)))
  {
    DBUG_ASSERT(table->s->table_category == TABLE_CATEGORY_LOG);
    /* Make sure all columns get assigned to a default value */
    table->use_all_columns();
    DBUG_ASSERT(table->no_replicate);
  }
  else
    thd->restore_backup_open_tables_state(backup);

  thd->utime_after_lock= save_utime_after_lock;
  DBUG_RETURN(table);
}


void drop_open_table(THD *thd, TABLE *table, const char *db_name,
                     const char *table_name)
{
  DBUG_ENTER("drop_open_table");
  if (table->s->tmp_table)
    thd->drop_temporary_table(table, NULL, true);
  else
  {
    DBUG_ASSERT(table == thd->open_tables);

    handlerton *table_type= table->s->db_type();
    table->file->extra(HA_EXTRA_PREPARE_FOR_DROP);
    close_thread_table(thd, &thd->open_tables);
    /* Remove the table share from the table cache. */
    tdc_remove_table(thd, TDC_RT_REMOVE_ALL, db_name, table_name,
                     FALSE);
    /* Remove the table from the storage engine and rm the .frm. */
    quick_rm_table(thd, table_type, db_name, table_name, 0);
 }
  DBUG_VOID_RETURN;
}


bool open_tables(THD *thd, const DDL_options_st &options,
                 TABLE_LIST **start, uint *counter, uint flags,
                 Prelocking_strategy *prelocking_strategy)
{
  /*
    We use pointers to "next_global" member in the last processed
    TABLE_LIST element and to the "next" member in the last processed
    Sroutine_hash_entry element as iterators over, correspondingly,
    the table list and stored routines list which stay valid and allow
    to continue iteration when new elements are added to the tail of
    the lists.
  */
  TABLE_LIST **table_to_open;
  Sroutine_hash_entry **sroutine_to_open;
  TABLE_LIST *tables;
  Open_table_context ot_ctx(thd, flags);
  bool error= FALSE;
  bool some_routine_modifies_data= FALSE;
  bool has_prelocking_list;
  DBUG_ENTER("open_tables");

  /* Data access in XA transaction is only allowed when it is active. */
  for (TABLE_LIST *table= *start; table; table= table->next_global)
    if (!table->schema_table)
    {
      enum xa_states xa_state= thd->transaction.xid_state.xa_state;
      if (xa_state == XA_IDLE || xa_state == XA_PREPARED)
      {
        my_error(ER_XAER_RMFAIL, MYF(0), xa_state_names[xa_state]);
        DBUG_RETURN(true);
      }
      else
        break;
    }

  thd->current_tablenr= 0;
restart:
  /*
    Close HANDLER tables which are marked for flush or against which there
    are pending exclusive metadata locks. This is needed both in order to
    avoid deadlocks and to have a point during statement execution at
    which such HANDLERs are closed even if they don't create problems for
    the current session (i.e. to avoid having a DDL blocked by HANDLERs
    opened for a long time).
  */
  if (thd->handler_tables_hash.records)
    mysql_ha_flush(thd);

  has_prelocking_list= thd->lex->requires_prelocking();
  table_to_open= start;
  sroutine_to_open= &thd->lex->sroutines_list.first;
  *counter= 0;
  THD_STAGE_INFO(thd, stage_opening_tables);
  prelocking_strategy->reset(thd);

  /*
    If we are executing LOCK TABLES statement or a DDL statement
    (in non-LOCK TABLES mode) we might have to acquire upgradable
    semi-exclusive metadata locks (SNW or SNRW) on some of the
    tables to be opened.
    When executing CREATE TABLE .. If NOT EXISTS .. SELECT, the
    table may not yet exist, in which case we acquire an exclusive
    lock.
    We acquire all such locks at once here as doing this in one
    by one fashion may lead to deadlocks or starvation. Later when
    we will be opening corresponding table pre-acquired metadata
    lock will be reused (thanks to the fact that in recursive case
    metadata locks are acquired without waiting).
  */
  if (! (flags & (MYSQL_OPEN_HAS_MDL_LOCK |
                  MYSQL_OPEN_FORCE_SHARED_MDL |
                  MYSQL_OPEN_FORCE_SHARED_HIGH_PRIO_MDL)))
  {
    if (thd->locked_tables_mode)
    {
      /*
        Under LOCK TABLES, we can't acquire new locks, so we instead
        need to check if appropriate locks were pre-acquired.
      */
      if (open_tables_check_upgradable_mdl(thd, *start,
                                           thd->lex->first_not_own_table(),
                                           flags))
      {
        error= TRUE;
        goto error;
      }
    }
    else
    {
      TABLE_LIST *table;
      if (lock_table_names(thd, options, *start,
                           thd->lex->first_not_own_table(),
                           ot_ctx.get_timeout(), flags))
      {
        error= TRUE;
        goto error;
      }
      for (table= *start; table && table != thd->lex->first_not_own_table();
           table= table->next_global)
      {
        if (table->mdl_request.type >= MDL_SHARED_UPGRADABLE)
          table->mdl_request.ticket= NULL;
      }
    }
  }

  /*
    Perform steps of prelocking algorithm until there are unprocessed
    elements in prelocking list/set.
  */
  while (*table_to_open  ||
         (thd->locked_tables_mode <= LTM_LOCK_TABLES && *sroutine_to_open))
  {
    /*
      For every table in the list of tables to open, try to find or open
      a table.
    */
    for (tables= *table_to_open; tables;
         table_to_open= &tables->next_global, tables= tables->next_global)
    {
      error= open_and_process_table(thd, tables, counter, flags,
                                    prelocking_strategy, has_prelocking_list,
                                    &ot_ctx);

      if (error)
      {
        if (ot_ctx.can_recover_from_failed_open())
        {
          /*
            We have met exclusive metadata lock or old version of table.
            Now we have to close all tables and release metadata locks.
            We also have to throw away set of prelocked tables (and thus
            close tables from this set that were open by now) since it
            is possible that one of tables which determined its content
            was changed.

            Instead of implementing complex/non-robust logic mentioned
            above we simply close and then reopen all tables.

            We have to save pointer to table list element for table which we
            have failed to open since closing tables can trigger removal of
            elements from the table list (if MERGE tables are involved),
          */
          close_tables_for_reopen(thd, start, ot_ctx.start_of_statement_svp());

          /*
            Here we rely on the fact that 'tables' still points to the valid
            TABLE_LIST element. Altough currently this assumption is valid
            it may change in future.
          */
          if (ot_ctx.recover_from_failed_open())
            goto error;

          /* Re-open temporary tables after close_tables_for_reopen(). */
          if (thd->open_temporary_tables(*start))
            goto error;

          error= FALSE;
          goto restart;
        }
        goto error;
      }

      DEBUG_SYNC(thd, "open_tables_after_open_and_process_table");
    }

    /*
      If we are not already in prelocked mode and extended table list is
      not yet built for our statement we need to cache routines it uses
      and build the prelocking list for it.
      If we are not in prelocked mode but have built the extended table
      list, we still need to call open_and_process_routine() to take
      MDL locks on the routines.
    */
    if (thd->locked_tables_mode <= LTM_LOCK_TABLES)
    {
      /*
        Process elements of the prelocking set which are present there
        since parsing stage or were added to it by invocations of
        Prelocking_strategy methods in the above loop over tables.

        For example, if element is a routine, cache it and then,
        if prelocking strategy prescribes so, add tables it uses to the
        table list and routines it might invoke to the prelocking set.
      */
      for (Sroutine_hash_entry *rt= *sroutine_to_open; rt;
           sroutine_to_open= &rt->next, rt= rt->next)
      {
        bool need_prelocking= false;
        bool routine_modifies_data;
        TABLE_LIST **save_query_tables_last= thd->lex->query_tables_last;

        error= open_and_process_routine(thd, thd->lex, rt, prelocking_strategy,
                                        has_prelocking_list, &ot_ctx,
                                        &need_prelocking,
                                        &routine_modifies_data);

        // Remember if any of SF modifies data.
        some_routine_modifies_data|= routine_modifies_data;

        if (need_prelocking && ! thd->lex->requires_prelocking())
          thd->lex->mark_as_requiring_prelocking(save_query_tables_last);

        if (need_prelocking && ! *start)
          *start= thd->lex->query_tables;

        if (error)
        {
          if (ot_ctx.can_recover_from_failed_open())
          {
            close_tables_for_reopen(thd, start,
                                    ot_ctx.start_of_statement_svp());
            if (ot_ctx.recover_from_failed_open())
              goto error;

            /* Re-open temporary tables after close_tables_for_reopen(). */
            if (thd->open_temporary_tables(*start))
              goto error;

            error= FALSE;
            goto restart;
          }
          /*
            Serious error during reading stored routines from mysql.proc table.
            Something is wrong with the table or its contents, and an error has
            been emitted; we must abort.
          */
          goto error;
        }
      }
    }
    if ((error= prelocking_strategy->handle_end(thd)))
      goto error;
  }

  /*
    After successful open of all tables, including MERGE parents and
    children, attach the children to their parents. At end of statement,
    the children are detached. Attaching and detaching are always done,
    even under LOCK TABLES.

    We also convert all TL_WRITE_DEFAULT and TL_READ_DEFAULT locks to
    appropriate "real" lock types to be used for locking and to be passed
    to storage engine.

    And start wsrep TOI if needed.
  */
  for (tables= *start; tables; tables= tables->next_global)
  {
    TABLE *tbl= tables->table;

    if (!tbl)
      continue;

    /* Schema tables may not have a TABLE object here. */
    if (tbl->file->ht->db_type == DB_TYPE_MRG_MYISAM)
    {
      /* MERGE tables need to access parent and child TABLE_LISTs. */
      DBUG_ASSERT(tbl->pos_in_table_list == tables);
      if (tbl->file->extra(HA_EXTRA_ATTACH_CHILDREN))
      {
        error= TRUE;
        goto error;
      }
    }

    /* Set appropriate TABLE::lock_type. */
    if (tbl && tables->lock_type != TL_UNLOCK && !thd->locked_tables_mode)
    {
      if (tables->lock_type == TL_WRITE_DEFAULT)
        tbl->reginfo.lock_type= thd->update_lock_default;
      else if (tables->lock_type == TL_READ_DEFAULT)
          tbl->reginfo.lock_type=
            read_lock_type_for_table(thd, thd->lex, tables,
                                     some_routine_modifies_data);
      else
        tbl->reginfo.lock_type= tables->lock_type;
    }
  }

  if (WSREP(thd)                                       &&
      wsrep_replicate_myisam                           &&
      (*start)                                         &&
      (*start)->table                                  &&
      (*start)->table->file->ht == myisam_hton         &&
      wsrep_thd_exec_mode(thd) == LOCAL_STATE          &&
      !is_stat_table((*start)->db, (*start)->alias)    &&
      thd->get_command() != COM_STMT_PREPARE           &&
      !thd->stmt_arena->is_stmt_prepare()              &&
      ((thd->lex->sql_command == SQLCOM_INSERT         ||
        thd->lex->sql_command == SQLCOM_INSERT_SELECT  ||
        thd->lex->sql_command == SQLCOM_REPLACE        ||
        thd->lex->sql_command == SQLCOM_REPLACE_SELECT ||
        thd->lex->sql_command == SQLCOM_UPDATE         ||
        thd->lex->sql_command == SQLCOM_UPDATE_MULTI   ||
        thd->lex->sql_command == SQLCOM_LOAD           ||
        thd->lex->sql_command == SQLCOM_DELETE)))
  {
    WSREP_TO_ISOLATION_BEGIN(NULL, NULL, (*start));
  }

error:
WSREP_ERROR_LABEL:
  THD_STAGE_INFO(thd, stage_after_opening_tables);
  thd_proc_info(thd, 0);

  if (error && *table_to_open)
  {
    (*table_to_open)->table= NULL;
  }
  DBUG_PRINT("open_tables", ("returning: %d", (int) error));
  DBUG_RETURN(error);
}


bool extend_table_list(THD *thd, TABLE_LIST *tables,
                       Prelocking_strategy *prelocking_strategy,
                       bool has_prelocking_list)
{
  bool error= false;
  LEX *lex= thd->lex;

  if (thd->locked_tables_mode <= LTM_LOCK_TABLES &&
      ! has_prelocking_list && tables->updating &&
      tables->lock_type >= TL_WRITE_ALLOW_WRITE)
  {
    bool need_prelocking= FALSE;
    TABLE_LIST **save_query_tables_last= lex->query_tables_last;
    /*
      Extend statement's table list and the prelocking set with
      tables and routines according to the current prelocking
      strategy.

      For example, for DML statements we need to add tables and routines
      used by triggers which are going to be invoked for this element of
      table list and also add tables required for handling of foreign keys.
    */
    error= prelocking_strategy->handle_table(thd, lex, tables,
                                             &need_prelocking);

    if (need_prelocking && ! lex->requires_prelocking())
      lex->mark_as_requiring_prelocking(save_query_tables_last);
  }
  return error;
}


fill_record(THD *thd, TABLE *table_arg, List<Item> &fields, List<Item> &values,
            bool ignore_errors, bool update)
{
  List_iterator_fast<Item> f(fields),v(values);
  Item *value, *fld;
  Item_field *field;
  bool save_abort_on_warning= thd->abort_on_warning;
  bool save_no_errors= thd->no_errors;
  DBUG_ENTER("fill_record");

  thd->no_errors= ignore_errors;
  /*
    Reset the table->auto_increment_field_not_null as it is valid for
    only one row.
  */
  if (fields.elements)
  {
    /*
      On INSERT or UPDATE fields are checked to be from the same table,
      thus we safely can take table from the first field.
    */
    fld= (Item_field*)f++;
    if (!(field= fld->field_for_view_update()))
    {
      my_error(ER_NONUPDATEABLE_COLUMN, MYF(0), fld->name);
      goto err;
    }
    DBUG_ASSERT(field->field->table == table_arg);
    table_arg->auto_increment_field_not_null= FALSE;
    f.rewind();
  }

  while ((fld= f++))
  {
    if (!(field= fld->field_for_view_update()))
    {
      my_error(ER_NONUPDATEABLE_COLUMN, MYF(0), fld->name);
      goto err;
    }
    value=v++;
    Field *rfield= field->field;
    TABLE* table= rfield->table;
    if (table->next_number_field &&
        rfield->field_index ==  table->next_number_field->field_index)
      table->auto_increment_field_not_null= TRUE;
    if (rfield->vcol_info &&
        !value->vcol_assignment_allowed_value() &&
        table->s->table_category != TABLE_CATEGORY_TEMPORARY)
    {
      push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
                          ER_WARNING_NON_DEFAULT_VALUE_FOR_VIRTUAL_COLUMN,
                          ER_THD(thd, ER_WARNING_NON_DEFAULT_VALUE_FOR_VIRTUAL_COLUMN),
                          rfield->field_name, table->s->table_name.str);
    }
    if (rfield->stored_in_db() &&
        (value->save_in_field(rfield, 0)) < 0 && !ignore_errors)
    {
      my_message(ER_UNKNOWN_ERROR, ER_THD(thd, ER_UNKNOWN_ERROR), MYF(0));
      goto err;
    }
    rfield->set_has_explicit_value();
  }

  if (update)
    table_arg->evaluate_update_default_function();
  else
    if (table_arg->default_field &&
        table_arg->update_default_fields(ignore_errors))
      goto err;

  /* Update virtual fields */
  if (table_arg->vfield &&
      table_arg->update_virtual_fields(table_arg->file, VCOL_UPDATE_FOR_WRITE))
    goto err;
  thd->abort_on_warning= save_abort_on_warning;
  thd->no_errors=        save_no_errors;
  DBUG_RETURN(thd->is_error());
err:
  DBUG_PRINT("error",("got error"));
  thd->abort_on_warning= save_abort_on_warning;
  thd->no_errors=        save_no_errors;
  if (fields.elements)
    table_arg->auto_increment_field_not_null= FALSE;
  DBUG_RETURN(TRUE);
}


static void mark_real_tables_as_free_for_reuse(TABLE_LIST *table_list)
{
  TABLE_LIST *table;
  for (table= table_list; table; table= table->next_global)
    if (!table->placeholder())
    {
      table->table->query_id= 0;
    }
  for (table= table_list; table; table= table->next_global)
    if (!table->placeholder())
    {
      /*
        Detach children of MyISAMMRG tables used in
        sub-statements, they will be reattached at open.
        This has to be done in a separate loop to make sure
        that children have had their query_id cleared.
      */
      table->table->file->extra(HA_EXTRA_DETACH_CHILDREN);
    }
}


bool is_locked_view(THD *thd, TABLE_LIST *t)
{
  DBUG_ENTER("check_locked_view");
  /*
   Is this table a view and not a base table?
   (it is work around to allow to open view with locked tables,
   real fix will be made after definition cache will be made)

   Since opening of view which was not explicitly locked by LOCK
   TABLES breaks metadata locking protocol (potentially can lead
   to deadlocks) it should be disallowed.
  */
  if (thd->mdl_context.is_lock_owner(MDL_key::TABLE,
                                     t->db, t->table_name,
                                     MDL_SHARED))
  {
    char path[FN_REFLEN + 1];
    build_table_filename(path, sizeof(path) - 1,
                         t->db, t->table_name, reg_ext, 0);
    /*
      Note that we can't be 100% sure that it is a view since it's
      possible that we either simply have not found unused TABLE
      instance in THD::open_tables list or were unable to open table
      during prelocking process (in this case in theory we still
      should hold shared metadata lock on it).
    */
    if (dd_frm_is_view(thd, path))
    {
      /*
        If parent_l of the table_list is non null then a merge table
        has this view as child table, which is not supported.
      */
      if (t->parent_l)
      {
        my_error(ER_WRONG_MRG_TABLE, MYF(0));
        DBUG_RETURN(FALSE);
      }

      if (!tdc_open_view(thd, t, CHECK_METADATA_VERSION))
      {
        DBUG_ASSERT(t->view != 0);
        DBUG_RETURN(TRUE); // VIEW
      }
    }
  }

  DBUG_RETURN(FALSE);
}


  Repair_mrg_table_error_handler()
    : m_handled_errors(false), m_unhandled_errors(false)
  {}


find_field_in_view(THD *thd, TABLE_LIST *table_list,
                   const char *name, uint length,
                   const char *item_name, Item **ref,
                   bool register_tree_change)
{
  DBUG_ENTER("find_field_in_view");
  DBUG_PRINT("enter",
             ("view: '%s', field name: '%s', item name: '%s', ref %p",
              table_list->alias, name, item_name, ref));
  Field_iterator_view field_it;
  field_it.set(table_list);
  Query_arena *arena= 0, backup;

  for (; !field_it.end_of_fields(); field_it.next())
  {
    if (!my_strcasecmp(system_charset_info, field_it.name(), name))
    {
      // in PS use own arena or data will be freed after prepare
      if (register_tree_change &&
          thd->stmt_arena->is_stmt_prepare_or_first_stmt_execute())
        arena= thd->activate_stmt_arena_if_needed(&backup);
      /*
        create_item() may, or may not create a new Item, depending on
        the column reference. See create_view_field() for details.
      */
      Item *item= field_it.create_item(thd);
      if (arena)
        thd->restore_active_arena(arena, &backup);

      if (!item)
        DBUG_RETURN(0);
      if (!ref)
        DBUG_RETURN((Field*) view_ref_found);
      /*
       *ref != NULL means that *ref contains the item that we need to
       replace. If the item was aliased by the user, set the alias to
       the replacing item.
       We need to set alias on both ref itself and on ref real item.
      */
      if (*ref && !(*ref)->is_autogenerated_name)
      {
        if (register_tree_change)
	{
          item->set_name_for_rollback(thd, (*ref)->name,
                                      (*ref)->name_length,
                                      system_charset_info);
          item->real_item()->set_name_for_rollback(thd, (*ref)->name,
                                                   (*ref)->name_length,
                                                   system_charset_info);
        }
        else
	{
          item->set_name(thd, (*ref)->name, (*ref)->name_length,
                         system_charset_info);
          item->real_item()->set_name(thd, (*ref)->name, (*ref)->name_length,
                                      system_charset_info);
        }
      }
      if (register_tree_change)
        thd->change_item_tree(ref, item);
      else
        *ref= item;
      DBUG_RETURN((Field*) view_ref_found);
    }
  }
  DBUG_RETURN(0);
}


void make_leaves_list(THD *thd, List<TABLE_LIST> &list, TABLE_LIST *tables,
                      bool full_table_list, TABLE_LIST *boundary)

{
  for (TABLE_LIST *table= tables; table; table= table->next_local)
  {
    if (table == boundary)
      full_table_list= !full_table_list;
    if (full_table_list && table->is_merged_derived())
    {
      SELECT_LEX *select_lex= table->get_single_select();
      /*
        It's safe to use select_lex->leaf_tables because all derived
        tables/views were already prepared and has their leaf_tables
        set properly.
      */
      make_leaves_list(thd, list, select_lex->get_table_list(),
      full_table_list, boundary);
    }
    else
    {
      list.push_back(table, thd->mem_root);
    }
  }
}


bool is_equal(const LEX_STRING *a, const LEX_STRING *b)
{
  return a->length == b->length && !strncmp(a->str, b->str, a->length);
}


Open_table_context::
request_backoff_action(enum_open_table_action action_arg,
                       TABLE_LIST *table)
{
  /*
    A back off action may be one of three kinds:

    * We met a broken table that needs repair, or a table that
      is not present on this MySQL server and needs re-discovery.
      To perform the action, we need an exclusive metadata lock on
      the table. Acquiring X lock while holding other shared
      locks can easily lead to deadlocks. We rely on MDL deadlock
      detector to discover them. If this is a multi-statement
      transaction that holds metadata locks for completed statements,
      we should keep these locks after discovery/repair.
      The action type in this case is OT_DISCOVER or OT_REPAIR.
    * Our attempt to acquire an MDL lock lead to a deadlock,
      detected by the MDL deadlock detector. The current
      session was chosen a victim. If this is a multi-statement
      transaction that holds metadata locks taken by completed
      statements, restarting locking for the current statement
      may lead to a livelock. Releasing locks of completed
      statements can not be done as will lead to violation
      of ACID. Thus, again, if m_has_locks is set,
      we report an error. Otherwise, when there are no metadata
      locks other than which belong to this statement, we can
      try to recover from error by releasing all locks and
      restarting the pre-locking.
      Similarly, a deadlock error can occur when the
      pre-locking process met a TABLE_SHARE that is being
      flushed, and unsuccessfully waited for the flush to
      complete. A deadlock in this case can happen, e.g.,
      when our session is holding a metadata lock that
      is being waited on by a session which is using
      the table which is being flushed. The only way
      to recover from this error is, again, to close all
      open tables, release all locks, and retry pre-locking.
      Action type name is OT_REOPEN_TABLES. Re-trying
      while holding some locks may lead to a livelock,
      and thus we don't do it.
    * Finally, this session has open TABLEs from different
      "generations" of the table cache. This can happen, e.g.,
      when, after this session has successfully opened one
      table used for a statement, FLUSH TABLES interfered and
      expelled another table used in it. FLUSH TABLES then
      blocks and waits on the table already opened by this
      statement.
      We detect this situation by ensuring that table cache
      version of all tables used in a statement is the same.
      If it isn't, all tables needs to be reopened.
      Note, that we can always perform a reopen in this case,
      even if we already have metadata locks, since we don't
      keep tables open between statements and a livelock
      is not possible.
  */
  if (action_arg == OT_BACKOFF_AND_RETRY && m_has_locks)
  {
    my_error(ER_LOCK_DEADLOCK, MYF(0));
    m_thd->mark_transaction_to_rollback(true);
    return TRUE;
  }
  /*
    If auto-repair or discovery are requested, a pointer to table
    list element must be provided.
  */
  if (table)
  {
    DBUG_ASSERT(action_arg == OT_DISCOVER || action_arg == OT_REPAIR);
    m_failed_table= (TABLE_LIST*) m_thd->alloc(sizeof(TABLE_LIST));
    if (m_failed_table == NULL)
      return TRUE;
    m_failed_table->init_one_table(table->db, table->db_length,
                                   table->table_name,
                                   table->table_name_length,
                                   table->alias, TL_WRITE);
    m_failed_table->open_strategy= table->open_strategy;
    m_failed_table->mdl_request.set_type(MDL_EXCLUSIVE);
  }
  m_action= action_arg;
  return FALSE;
}


Repair_mrg_table_error_handler::handle_condition(THD *,
                                                 uint sql_errno,
                                                 const char*,
                                                 Sql_condition::enum_warning_level *level,
                                                 const char*,
                                                 Sql_condition ** cond_hdl)
{
  *cond_hdl= NULL;
  if (sql_errno == ER_NO_SUCH_TABLE ||
      sql_errno == ER_NO_SUCH_TABLE_IN_ENGINE ||
      sql_errno == ER_WRONG_MRG_TABLE)
  {
    m_handled_errors= true;
    return TRUE;
  }

  m_unhandled_errors= true;
  return FALSE;
}


store_natural_using_join_columns(THD *thd, TABLE_LIST *natural_using_join,
                                 TABLE_LIST *table_ref_1,
                                 TABLE_LIST *table_ref_2,
                                 List<String> *using_fields,
                                 uint found_using_fields)
{
  Field_iterator_table_ref it_1, it_2;
  Natural_join_column *nj_col_1, *nj_col_2;
  Query_arena *arena, backup;
  bool result= TRUE;
  List<Natural_join_column> *non_join_columns;
  List<Natural_join_column> *join_columns;
  DBUG_ENTER("store_natural_using_join_columns");

  DBUG_ASSERT(!natural_using_join->join_columns);

  arena= thd->activate_stmt_arena_if_needed(&backup);

  if (!(non_join_columns= new List<Natural_join_column>) ||
      !(join_columns= new List<Natural_join_column>))
    goto err;

  /* Append the columns of the first join operand. */
  for (it_1.set(table_ref_1); !it_1.end_of_fields(); it_1.next())
  {
    nj_col_1= it_1.get_natural_column_ref();
    if (nj_col_1->is_common)
    {
      join_columns->push_back(nj_col_1, thd->mem_root);
      /* Reset the common columns for the next call to mark_common_columns. */
      nj_col_1->is_common= FALSE;
    }
    else
      non_join_columns->push_back(nj_col_1, thd->mem_root);
  }

  /*
    Check that all columns in the USING clause are among the common
    columns. If this is not the case, report the first one that was
    not found in an error.
  */
  if (using_fields && found_using_fields < using_fields->elements)
  {
    String *using_field_name;
    List_iterator_fast<String> using_fields_it(*using_fields);
    while ((using_field_name= using_fields_it++))
    {
      const char *using_field_name_ptr= using_field_name->c_ptr();
      List_iterator_fast<Natural_join_column>
        it(*join_columns);
      Natural_join_column *common_field;

      for (;;)
      {
        /* If reached the end of fields, and none was found, report error. */
        if (!(common_field= it++))
        {
          my_error(ER_BAD_FIELD_ERROR, MYF(0), using_field_name_ptr,
                   current_thd->where);
          goto err;
        }
        if (!my_strcasecmp(system_charset_info,
                           common_field->name(), using_field_name_ptr))
          break;                                // Found match
      }
    }
  }

  /* Append the non-equi-join columns of the second join operand. */
  for (it_2.set(table_ref_2); !it_2.end_of_fields(); it_2.next())
  {
    nj_col_2= it_2.get_natural_column_ref();
    if (!nj_col_2->is_common)
      non_join_columns->push_back(nj_col_2, thd->mem_root);
    else
    {
      /* Reset the common columns for the next call to mark_common_columns. */
      nj_col_2->is_common= FALSE;
    }
  }

  if (non_join_columns->elements > 0)
    join_columns->append(non_join_columns);
  natural_using_join->join_columns= join_columns;
  natural_using_join->is_join_columns_complete= TRUE;

  result= FALSE;

  if (arena)
    thd->restore_active_arena(arena, &backup);
  DBUG_RETURN(result);

err:
  /*
     Actually we failed to build join columns list, so we have to
     clear it to avoid problems with half-build join on next run.
     The list was created in mark_common_columns().
   */
  table_ref_1->remove_join_columns();
  table_ref_2->remove_join_columns();

  if (arena)
    thd->restore_active_arena(arena, &backup);
  DBUG_RETURN(TRUE);
}


thr_lock_type read_lock_type_for_table(THD *thd,
                                       Query_tables_list *prelocking_ctx,
                                       TABLE_LIST *table_list,
                                       bool routine_modifies_data)
{
  /*
    In cases when this function is called for a sub-statement executed in
    prelocked mode we can't rely on OPTION_BIN_LOG flag in THD::options
    bitmap to determine that binary logging is turned on as this bit can
    be cleared before executing sub-statement. So instead we have to look
    at THD::variables::sql_log_bin member.
  */
  bool log_on= mysql_bin_log.is_open() && thd->variables.sql_log_bin;
  if ((log_on == FALSE) || (thd->wsrep_binlog_format() == BINLOG_FORMAT_ROW) ||
      (table_list->table->s->table_category == TABLE_CATEGORY_LOG) ||
      (table_list->table->s->table_category == TABLE_CATEGORY_PERFORMANCE) ||
      !(is_update_query(prelocking_ctx->sql_command) ||
        (routine_modifies_data && table_list->prelocking_placeholder) ||
        (thd->locked_tables_mode > LTM_LOCK_TABLES)))
    return TL_READ;
  else
    return TL_READ_NO_INSERT;
}


void promote_select_describe_flag_if_needed(LEX *lex)
{
  if (lex->describe)
  {
    lex->select_lex.options |= SELECT_DESCRIBE;
  }
}


bool setup_on_expr(THD *thd, TABLE_LIST *table, bool is_update)
{
  uchar buff[STACK_BUFF_ALLOC];			// Max argument in function
  if (check_stack_overrun(thd, STACK_MIN_SIZE, buff))
    return TRUE;				// Fatal error flag is set!
  for(; table; table= table->next_local)
  {
    TABLE_LIST *embedded; /* The table at the current level of nesting. */
    TABLE_LIST *embedding= table; /* The parent nested table reference. */
    do
    {
      embedded= embedding;
      if (embedded->on_expr)
      {
        thd->where="on clause";
        embedded->on_expr->mark_as_condition_AND_part(embedded);
        if ((!embedded->on_expr->fixed &&
             embedded->on_expr->fix_fields(thd, &embedded->on_expr)) ||
            embedded->on_expr->check_cols(1))
          return TRUE;
      }
      /*
        If it's a semi-join nest, fix its "left expression", as it is used by
        the SJ-Materialization
      */
      if (embedded->sj_subq_pred)
      {
        Item **left_expr= &embedded->sj_subq_pred->left_expr;
        if (!(*left_expr)->fixed && (*left_expr)->fix_fields(thd, left_expr))
          return TRUE;
      }

      embedding= embedded->embedding;
    }
    while (embedding &&
           embedding->nested_join->join_list.head() == embedded);

    if (table->is_merged_derived())
    {
      SELECT_LEX *select_lex= table->get_single_select();
      setup_on_expr(thd, select_lex->get_table_list(), is_update);
    }

    /* process CHECK OPTION */
    if (is_update)
    {
      TABLE_LIST *view= table->top_table();
      if (view->effective_with_check)
      {
        if (view->prepare_check_option(thd))
          return TRUE;
        thd->change_item_tree(&table->check_option, view->check_option);
      }
    }
  }
  return FALSE;
}


static bool check_lock_and_start_stmt(THD *thd,
                                      Query_tables_list *prelocking_ctx,
                                      TABLE_LIST *table_list)
{
  int error;
  thr_lock_type lock_type;
  DBUG_ENTER("check_lock_and_start_stmt");

  /*
    Prelocking placeholder is not set for TABLE_LIST that
    are directly used by TOP level statement.
  */
  DBUG_ASSERT(table_list->prelocking_placeholder == false);

  /*
    TL_WRITE_DEFAULT and TL_READ_DEFAULT are supposed to be parser only
    types of locks so they should be converted to appropriate other types
    to be passed to storage engine. The exact lock type passed to the
    engine is important as, for example, InnoDB uses it to determine
    what kind of row locks should be acquired when executing statement
    in prelocked mode or under LOCK TABLES with @@innodb_table_locks = 0.

    Last argument routine_modifies_data for read_lock_type_for_table()
    is ignored, as prelocking placeholder will never be set here.
  */
  DBUG_ASSERT(table_list->prelocking_placeholder == false);
  if (table_list->lock_type == TL_WRITE_DEFAULT)
    lock_type= thd->update_lock_default;
  else if (table_list->lock_type == TL_READ_DEFAULT)
    lock_type= read_lock_type_for_table(thd, prelocking_ctx, table_list, true);
  else
    lock_type= table_list->lock_type;

  if ((int) lock_type > (int) TL_WRITE_ALLOW_WRITE &&
      (int) table_list->table->reginfo.lock_type <= (int) TL_WRITE_ALLOW_WRITE)
  {
    my_error(ER_TABLE_NOT_LOCKED_FOR_WRITE, MYF(0),
             table_list->table->alias.c_ptr());
    DBUG_RETURN(1);
  }
  if ((error= table_list->table->file->start_stmt(thd, lock_type)))
  {
    table_list->table->file->print_error(error, MYF(0));
    DBUG_RETURN(1);
  }

  /*
    Record in transaction state tracking
  */
  TRANSACT_TRACKER(add_trx_state(thd, lock_type,
                                 table_list->table->file->has_transactions()));

  DBUG_RETURN(0);
}


Locked_tables_list::init_locked_tables(THD *thd)
{
  DBUG_ASSERT(thd->locked_tables_mode == LTM_NONE);
  DBUG_ASSERT(m_locked_tables == NULL);
  DBUG_ASSERT(m_reopen_array == NULL);
  DBUG_ASSERT(m_locked_tables_count == 0);

  for (TABLE *table= thd->open_tables; table;
       table= table->next, m_locked_tables_count++)
  {
    TABLE_LIST *src_table_list= table->pos_in_table_list;
    char *db, *table_name, *alias;
    size_t db_len=         table->s->db.length;
    size_t table_name_len= table->s->table_name.length;
    size_t alias_len=      table->alias.length();
    TABLE_LIST *dst_table_list;

    if (! multi_alloc_root(&m_locked_tables_root,
                           &dst_table_list, sizeof(*dst_table_list),
                           &db, db_len + 1,
                           &table_name, table_name_len + 1,
                           &alias, alias_len + 1,
                           NullS))
    {
      reset();
      return TRUE;
    }

    memcpy(db,         table->s->db.str, db_len + 1);
    memcpy(table_name, table->s->table_name.str, table_name_len + 1);
    strmake(alias,     table->alias.ptr(), alias_len);
    dst_table_list->init_one_table(db, db_len, table_name, table_name_len,
                                   alias, table->reginfo.lock_type);
    dst_table_list->table= table;
    dst_table_list->mdl_request.ticket= src_table_list->mdl_request.ticket;

    /* Link last into the list of tables */
    *(dst_table_list->prev_global= m_locked_tables_last)= dst_table_list;
    m_locked_tables_last= &dst_table_list->next_global;
    table->pos_in_locked_tables= dst_table_list;
  }
  if (m_locked_tables_count)
  {
    /**
      Allocate an auxiliary array to pass to mysql_lock_tables()
      in reopen_tables(). reopen_tables() is a critical
      path and we don't want to complicate it with extra allocations.
    */
    m_reopen_array= (TABLE_LIST**)alloc_root(&m_locked_tables_root,
                                             sizeof(TABLE_LIST*) *
                                             (m_locked_tables_count+1));
    if (m_reopen_array == NULL)
    {
      reset();
      return TRUE;
    }
  }

  TRANSACT_TRACKER(add_trx_state(thd, TX_LOCKED_TABLES));

  thd->enter_locked_tables_mode(LTM_LOCK_TABLES);

  return FALSE;
}


lock_table_names(THD *thd, const DDL_options_st &options,
                 TABLE_LIST *tables_start, TABLE_LIST *tables_end,
                 ulong lock_wait_timeout, uint flags)
{
  MDL_request_list mdl_requests;
  TABLE_LIST *table;
  MDL_request global_request;
  ulong org_lock_wait_timeout= lock_wait_timeout;
  /* Check if we are using CREATE TABLE ... IF NOT EXISTS */
  bool create_table;
  Dummy_error_handler error_handler;
  DBUG_ENTER("lock_table_names");

  DBUG_ASSERT(!thd->locked_tables_mode);

  for (table= tables_start; table && table != tables_end;
       table= table->next_global)
  {
    if (table->mdl_request.type < MDL_SHARED_UPGRADABLE ||
        table->mdl_request.type == MDL_SHARED_READ_ONLY ||
        table->open_type == OT_TEMPORARY_ONLY ||
        (table->open_type == OT_TEMPORARY_OR_BASE && is_temporary_table(table)))
    {
      continue;
    }

    /* Write lock on normal tables is not allowed in a read only transaction. */
    if (thd->tx_read_only)
    {
      my_error(ER_CANT_EXECUTE_IN_READ_ONLY_TRANSACTION, MYF(0));
      DBUG_RETURN(true);
    }

    /* Scoped locks: Take intention exclusive locks on all involved schemas. */
    if (!(flags & MYSQL_OPEN_SKIP_SCOPED_MDL_LOCK))
    {
      MDL_request *schema_request= new (thd->mem_root) MDL_request;
      if (schema_request == NULL)
        DBUG_RETURN(TRUE);
      schema_request->init(MDL_key::SCHEMA, table->db, "",
                           MDL_INTENTION_EXCLUSIVE,
                           MDL_TRANSACTION);
      mdl_requests.push_front(schema_request);
    }

    mdl_requests.push_front(&table->mdl_request);
  }

  if (mdl_requests.is_empty())
    DBUG_RETURN(FALSE);

  /* Check if CREATE TABLE without REPLACE was used */
  create_table= thd->lex->sql_command == SQLCOM_CREATE_TABLE &&
                !options.or_replace();

  if (!(flags & MYSQL_OPEN_SKIP_SCOPED_MDL_LOCK))
  {
    /*
      Protect this statement against concurrent global read lock
      by acquiring global intention exclusive lock with statement
      duration.
    */
    if (thd->global_read_lock.can_acquire_protection())
      DBUG_RETURN(TRUE);
    global_request.init(MDL_key::GLOBAL, "", "", MDL_INTENTION_EXCLUSIVE,
                        MDL_STATEMENT);
    mdl_requests.push_front(&global_request);

    if (create_table)
#ifdef WITH_WSREP
      if (!(thd->lex->sql_command == SQLCOM_CREATE_TABLE &&
	    thd->wsrep_exec_mode == REPL_RECV))
#endif
      lock_wait_timeout= 0;                     // Don't wait for timeout
  }

  for (;;)
  {
    if (create_table)
      thd->push_internal_handler(&error_handler);  // Avoid warnings & errors
    bool res= thd->mdl_context.acquire_locks(&mdl_requests, lock_wait_timeout);
    if (create_table)
      thd->pop_internal_handler();

    if (!res)
      DBUG_RETURN(FALSE);                       // Got locks

    if (!create_table)
      DBUG_RETURN(TRUE);                        // Return original error

    /*
      We come here in the case of lock timeout when executing CREATE TABLE.
      Verify that table does exist (it usually does, as we got a lock conflict)
    */
    if (ha_table_exists(thd, tables_start->db, tables_start->table_name))
    {
      if (options.if_not_exists())
      {
        push_warning_printf(thd, Sql_condition::WARN_LEVEL_NOTE,
                            ER_TABLE_EXISTS_ERROR,
                            ER_THD(thd, ER_TABLE_EXISTS_ERROR),
                            tables_start->table_name);
      }
      else
        my_error(ER_TABLE_EXISTS_ERROR, MYF(0), tables_start->table_name);
      DBUG_RETURN(TRUE);
    }
    /*
      We got error from acquire_locks, but the table didn't exists.
      This could happen if another connection runs a statement
      involving this non-existent table, and this statement took the mdl,
      but didn't error out with ER_NO_SUCH_TABLE yet (yes, a race condition).
      We play safe and restart the original acquire_locks with the
      original timeout.
    */
    create_table= 0;
    lock_wait_timeout= org_lock_wait_timeout;
  }
}


void close_thread_table(THD *thd, TABLE **table_ptr)
{
  TABLE *table= *table_ptr;
  DBUG_ENTER("close_thread_table");
  DBUG_PRINT("tcache", ("table: '%s'.'%s' %p", table->s->db.str,
                        table->s->table_name.str, table));
  DBUG_ASSERT(!table->file->keyread_enabled());
  DBUG_ASSERT(!table->file || table->file->inited == handler::NONE);

  /*
    The metadata lock must be released after giving back
    the table to the table cache.
  */
  DBUG_ASSERT(thd->mdl_context.is_lock_owner(MDL_key::TABLE,
                                             table->s->db.str,
                                             table->s->table_name.str,
                                             MDL_SHARED));
  table->mdl_ticket= NULL;

  if (table->file)
  {
    table->file->update_global_table_stats();
    table->file->update_global_index_stats();
  }

  mysql_mutex_lock(&thd->LOCK_thd_data);
  *table_ptr=table->next;
  mysql_mutex_unlock(&thd->LOCK_thd_data);

  if (! table->needs_reopen())
  {
    /* Avoid having MERGE tables with attached children in table cache. */
    table->file->extra(HA_EXTRA_DETACH_CHILDREN);
    /* Free memory and reset for next loop. */
    free_field_buffers_larger_than(table, MAX_TDC_BLOB_SIZE);
    table->file->ha_reset();
  }

  /*
    Do this *before* entering the TABLE_SHARE::tdc.LOCK_table_share
    critical section.
  */
  MYSQL_UNBIND_TABLE(table->file);

  tc_release_table(table);
  DBUG_VOID_RETURN;
}


void Locked_tables_list::unlink_from_list(THD *thd,
                                          TABLE_LIST *table_list,
                                          bool remove_from_locked_tables)
{
  /*
    If mode is not LTM_LOCK_TABLES, we needn't do anything. Moreover,
    outside this mode pos_in_locked_tables value is not trustworthy.
  */
  if (thd->locked_tables_mode != LTM_LOCK_TABLES &&
      thd->locked_tables_mode != LTM_PRELOCKED_UNDER_LOCK_TABLES)
    return;

  /*
    table_list must be set and point to pos_in_locked_tables of some
    table.
  */
  DBUG_ASSERT(table_list->table->pos_in_locked_tables == table_list);

  /* Clear the pointer, the table will be returned to the table cache. */
  table_list->table->pos_in_locked_tables= NULL;

  /* Mark the table as closed in the locked tables list. */
  table_list->table= NULL;

  /*
    If the table is being dropped or renamed, remove it from
    the locked tables list (implicitly drop the LOCK TABLES lock
    on it).
  */
  if (remove_from_locked_tables)
  {
    *table_list->prev_global= table_list->next_global;
    if (table_list->next_global == NULL)
      m_locked_tables_last= table_list->prev_global;
    else
      table_list->next_global->prev_global= table_list->prev_global;
    m_locked_tables_count--;
  }
}


int setup_ftfuncs(SELECT_LEX *select_lex)
{
  List_iterator<Item_func_match> li(*(select_lex->ftfunc_list)),
                                 lj(*(select_lex->ftfunc_list));
  Item_func_match *ftf, *ftf2;

  while ((ftf=li++))
  {
    if (ftf->fix_index())
      return 1;
    lj.rewind();
    while ((ftf2=lj++) != ftf)
    {
      if (ftf->eq(ftf2,1) && !ftf2->master)
        ftf2->master=ftf;
    }
  }

  return 0;
}


bool setup_tables(THD *thd, Name_resolution_context *context,
                  List<TABLE_LIST> *from_clause, TABLE_LIST *tables,
                  List<TABLE_LIST> &leaves, bool select_insert,
                  bool full_table_list)
{
  uint tablenr= 0;
  List_iterator<TABLE_LIST> ti(leaves);
  TABLE_LIST *table_list;

  DBUG_ENTER("setup_tables");

  DBUG_ASSERT ((select_insert && !tables->next_name_resolution_table) || !tables ||
               (context->table_list && context->first_name_resolution_table));
  /*
    this is used for INSERT ... SELECT.
    For select we setup tables except first (and its underlying tables)
  */
  TABLE_LIST *first_select_table= (select_insert ?
                                   tables->next_local:
                                   0);
  SELECT_LEX *select_lex= select_insert ? &thd->lex->select_lex :
                                          thd->lex->current_select;
  if (select_lex->first_cond_optimization)
  {
    leaves.empty();
    if (select_lex->prep_leaf_list_state != SELECT_LEX::SAVED)
    {
      make_leaves_list(thd, leaves, tables, full_table_list, first_select_table);
      select_lex->prep_leaf_list_state= SELECT_LEX::READY;
      select_lex->leaf_tables_exec.empty();
    }
    else
    {
      List_iterator_fast <TABLE_LIST> ti(select_lex->leaf_tables_prep);
      while ((table_list= ti++))
        leaves.push_back(table_list, thd->mem_root);
    }

    while ((table_list= ti++))
    {
      TABLE *table= table_list->table;
      if (table)
        table->pos_in_table_list= table_list;
      if (first_select_table &&
          table_list->top_table() == first_select_table)
      {
        /* new counting for SELECT of INSERT ... SELECT command */
        first_select_table= 0;
        thd->lex->select_lex.insert_tables= tablenr;
        tablenr= 0;
      }
      if(table_list->jtbm_subselect)
      {
        table_list->jtbm_table_no= tablenr;
      }
      else if (table)
      {
        table->pos_in_table_list= table_list;
        setup_table_map(table, table_list, tablenr);

        if (table_list->process_index_hints(table))
          DBUG_RETURN(1);
      }
      tablenr++;
    }
    if (tablenr > MAX_TABLES)
    {
      my_error(ER_TOO_MANY_TABLES,MYF(0), static_cast<int>(MAX_TABLES));
      DBUG_RETURN(1);
    }
  }
  else
  {
    List_iterator_fast <TABLE_LIST> ti(select_lex->leaf_tables_exec);
    select_lex->leaf_tables.empty();
    while ((table_list= ti++))
    {
      if(table_list->jtbm_subselect)
      {
        table_list->jtbm_table_no= table_list->tablenr_exec;
      }
      else
      {
        table_list->table->tablenr= table_list->tablenr_exec;
        table_list->table->map= table_list->map_exec;
        table_list->table->maybe_null= table_list->maybe_null_exec;
        table_list->table->pos_in_table_list= table_list;
        if (table_list->process_index_hints(table_list->table))
          DBUG_RETURN(1);
      }
      select_lex->leaf_tables.push_back(table_list);
    }
  }

  for (table_list= tables;
       table_list;
       table_list= table_list->next_local)
  {
    if (table_list->merge_underlying_list)
    {
      DBUG_ASSERT(table_list->is_merged_derived());
      Query_arena *arena, backup;
      arena= thd->activate_stmt_arena_if_needed(&backup);
      bool res;
      res= table_list->setup_underlying(thd);
      if (arena)
        thd->restore_active_arena(arena, &backup);
      if (res)
        DBUG_RETURN(1);
    }

    if (table_list->jtbm_subselect)
    {
      Item *item= table_list->jtbm_subselect->optimizer;
      if (!table_list->jtbm_subselect->optimizer->fixed &&
          table_list->jtbm_subselect->optimizer->fix_fields(thd, &item))
      {
        my_error(ER_TOO_MANY_TABLES,MYF(0), static_cast<int>(MAX_TABLES)); /* psergey-todo: WHY ER_TOO_MANY_TABLES ???*/
        DBUG_RETURN(1);
      }
      DBUG_ASSERT(item == table_list->jtbm_subselect->optimizer);
    }
  }

  /* Precompute and store the row types of NATURAL/USING joins. */
  if (setup_natural_join_row_types(thd, from_clause, context))
    DBUG_RETURN(1);

  DBUG_RETURN(0);
}