Duplicate entry in menu.inc on line 2385

The same with combination of actions related to FeedAPI, Views and Panels.

user warning: Duplicate entry 'admin/settings/user_stats/reset' for key 1 query: INSERT INTO m_menu_router (path, load_functions, to_arg_functions, access_callback, access_arguments, page_callback, page_arguments, fit, number_parts, tab_parent, tab_root, title, title_callback, title_arguments, type, block_callback, description, position, weight, file) VALUES ('admin/settings/user_stats/reset', '', '', 'user_access', 'a:1:{i:0;s:21:\"administer user stats\";}', 'drupal_get_form', 'a:1:{i:0;s:34:\"user_stats_reset_postcount_confirm\";}', 15, 4, '', 'admin/settings/user_stats/reset', 'reset user post stats', 't', '', 4, '', '', '', 0, '') in /includes/menu.inc on line 2385.
user warning: Duplicate entry 'book/export/%/%' for key 1 query: INSERT INTO m_menu_router (path, load_functions, to_arg_functions, access_callback, access_arguments, page_callback, page_arguments, fit, number_parts, tab_parent, tab_root, title, title_callback, title_arguments, type, block_callback, description, position, weight, file) VALUES ('book/export/%/%', 'a:2:{i:2;N;i:3;N;}', '', 'user_access', 'a:1:{i:0;s:31:\"access printer-friendly version\";}', 'book_export', 'a:2:{i:0;i:2;i:1;i:3;}', 12, 4, '', 'book/export/%/%', '', 't', '', 4, '', '', '', 0, 'modules/book/book.pages.inc') in /includes/menu.inc on line 2385.
...
(many of them)

function _menu_router_build($callbacks) {
...
  // Delete the existing router since we have some data to replace it.
  db_query('DELETE FROM {menu_router}');
...
    $title_arguments = $item['title arguments'] ? serialize($item['title arguments']) : '';
    db_query("INSERT INTO {menu_router}
      (path, load_functions, to_arg_functions, access_callback,
      access_arguments, page_callback, page_arguments, fit,
      number_parts, tab_parent, tab_root,
      title, title_callback, title_arguments,
      type, block_callback, description, position, weight, file)
      VALUES ('%s', '%s', '%s', '%s',
      '%s', '%s', '%s', %d,
      %d, '%s', '%s',
      '%s', '%s', '%s',
      %d, '%s', '%s', '%s', %d, '%s')",
      $path, $item['load_functions'], $item['to_arg_functions'], $item['access callback'],
      serialize($item['access arguments']), $item['page callback'], serialize($item['page arguments']), $item['_fit'],
      $item['_number_parts'], $item['tab_parent'], $item['tab_root'],
      $item['title'], $item['title callback'], $title_arguments,
      $item['type'], $item['block callback'], $item['description'], $item['position'], $item['weight'], $item['include file']);
  }

What if there were two Drupal instances and two rebuilds in the same time?

Result:

Type	page not found
Date	Friday, January 23, 2009 - 05:00
User	admin
Location	/panels/ajax/add-pane/1/middle
Referrer	/admin/panels/panel-page/strona_glowna/edit/content
Message	panels/ajax/add-pane/1/middle
Severity	warning
Hostname	82.35.148.244
Operations

Type	php
Date	Friday, January 23, 2009 - 05:00
User	admin
Location	/panels/ajax/add-pane/1/middle
Referrer	/admin/panels/panel-page/strona_glowna/edit/content
Message	The specialized Panels menu router rebuild failed. Some paths may not work correctly.
Severity	error
Hostname	82.35.148.244
Operations	

and 8 pages of Duplicated errors in watchdog in the same time;/

#352978: Attempt to insert duplicate entry into menu_router table warnings when editing content types Blog and Forum Post

Proper duplicated issue: #238760: menu_router table truncated and site goes down