[wp-trac] [WordPress Trac] #41662: Don't prime menu item cache if a persistent cache is being used

[WordPress Trac]

#41662: Don't prime menu item cache if a persistent cache is being used
--------------------------+-----------------------------
 Reporter:  david.binda   |      Owner:
     Type:  defect (bug)  |     Status:  new
 Priority:  normal        |  Milestone:  Awaiting Review
Component:  Menus         |    Version:  trunk
 Severity:  normal        |   Keywords:
  Focuses:  performance   |
--------------------------+-----------------------------
 In terms of #12734 a r14560 have been introduced. However, while the
 commit message says following:

 > Don't prime menu item cache if a persistent cache is being used. Prime
 the menu item cache only on the first call to wp_get_nav_menu_items().
 Avoids unneeded queries when wp_get_nav_menu_items() is called repeatedly.
 see #12734

 The code introduced in the revision says following:

 {{{#!php
 // Get all posts and terms at once to prime the caches
 if ( empty($fetched[$menu->term_id]) || $_wp_using_ext_object_cache ) {
 }}}

 The condition check for whether the currently processed `term_id` has
 already been fetched (eg.: during repeated call to `wp_nav_menu`) by
 checking for the key in static variable `$fetched` or whether external
 object cache is in use.

 The, imho, faulty part of the condition is the `||
 $_wp_using_ext_object_cache` (or currently used `||
 wp_using_ext_object_cache()`) as it says, prime caches always, in case
 external object cache is being used.

 The conditional, imho, should state `&& ! wp_using_ext_object_cache()`.
 Testing this change on a WordPress install without persistent object cache
 backend shows no difference in behaviour (as expected), and testing the
 change on the same WordPress install after enabling persistent object
 cache backend shows decrease in the number of SQL queries performed by
 `wp_nav_menu` call.

--
Ticket URL: <https://core.trac.wordpress.org/ticket/41662>
WordPress Trac <https://core.trac.wordpress.org/>
WordPress publishing platform