Deletes postmeta duplicates

wordpress_repair.php

<?php
# Copyright Alexandre Syenchuk, 2012
# a multi-site, multi-duplicates version of https://gist.github.com/1177018

header('Content-type: text/plain; charset=utf-8');

include('wp-config.php');
include('wp-load.php');

global $wpdb;

$req_tpl = <<<eof
DELETE FROM %s
WHERE meta_key = '_mf_write_panel_id'
	AND post_id IN (SELECT * FROM (
		SELECT post_id
		FROM %s
		WHERE meta_key = '_mf_write_panel_id'
		GROUP BY post_id
		HAVING COUNT(post_id) > 1
	) AS tmp1)
	AND meta_id NOT IN (SELECT * FROM (
		SELECT meta_id
		FROM %s
		WHERE meta_key = '_mf_write_panel_id'
		GROUP BY post_id
		HAVING COUNT(post_id) > 1
	) AS tmp2)
;
eof;

$blogs = $wpdb->get_results("SELECT blog_id FROM $wpdb->blogs");

foreach ($blogs as $blog)
{
  $blog_id = $blog->blog_id;
  $table = $wpdb->get_blog_prefix($blog->blog_id).'postmeta';
  $req = str_replace('%s',$table,$req_tpl);
  $changes = $wpdb->query($req);
  echo "$blog_id : ".($changes ? "$changes modifications" : "ok")."\n";
}
?>