[wp-trac] [WordPress Trac] #25178: multisite network admin to delete user attempts to load millions of users into memory

[WordPress Trac]

#25178: multisite network admin to delete user attempts to load millions of users
into memory
--------------------------+-----------------------------
 Reporter:  _ck_          |      Owner:
     Type:  defect (bug)  |     Status:  new
 Priority:  normal        |  Milestone:  Awaiting Review
Component:  Multisite     |    Version:  3.6
 Severity:  major         |   Keywords:
--------------------------+-----------------------------
 There is an unbound mysql query in multisite network admin.


 {{{
 $blog_users = get_users( array( 'blog_id' => $details->userblog_id ) );
 }}}

 around line 53 in  `wp-admin/network/users.php`

 If there are millions of users with wp_capabilities, it will attempt to
 load all of them into memory at once.

 Then it attempts to do a one-by-one comparison in a php loop.

 This entire section of code needs to be rewritten to simply load the users
 by id and simply do a ` LIKE '%\_capabilities' ` then compare their
 capabilities against the requested blog ids. Or even better since you know
 the blog ids and capabilities, just request the specific `meta_key` ie.
 wp_123_capabilities which would be way faster because it has an index.

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Ticket URL: <http://core.trac.wordpress.org/ticket/25178>
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