Checking if _admin_notice_post_locked should be called can slow down the post editing

[berislav.grgicak]

On wp-admin/edit-form-advanced.php:28, WordPress checks if multiple users exist to call _admin_notice_post_locked.

In some cases, plugins add additional filters to all get_users calls to ensure that a user role doesn't have access to private data.
If these checks use meta value comparisons, it can slow post-editing on sites with large user_meta tables.

The root cause of this issue is how WordPress stores and validates user capabilities, but the _admin_notice_post_locked check could be optimized without fixing the root cause.

Some suggestions on how to fix this would be:

• caching the $check_users value
• using a boolean option that is true if a site has multiple users
• adding a filter that allows manually setting $check_users to skip this check

[costdev]

Hi @berislavgrgicak, welcome to Trac!

I'm just modifying the ticket's parameters to help get this some more focus and help to track down when this was introduced.

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This check was introduced in WordPress 4.9.

• Changeset: [41829]
• Ticket: #42119

[berislav.grgicak]

Thank you @costdev!

I would be happy to help with this, but I'm not sure what would be the best way to improve the performance.