[wp-trac] [WordPress Trac] #59592: Store last changed value in key instead of using it as a salt for query caches

[WordPress Trac]

#59592: Store last changed value in key instead of using it as a salt for query
caches
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 Reporter:  spacedmonkey              |       Owner:  (none)
     Type:  enhancement               |      Status:  new
 Priority:  normal                    |   Milestone:  Future Release
Component:  Cache API                 |     Version:
 Severity:  normal                    |  Resolution:
 Keywords:  has-patch has-unit-tests  |     Focuses:  performance
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Comment (by peterwilsoncc):

 As a concept I like this idea for the `*-queries` groups, taking @rmccue,
 @tillkruess, @sanchothefat's word on the improved efficiency for large
 sites.

 On the proposed implementation, I am wondeing if it would be better to
 introduce new `wp_cache` functions to do the checking of the last changed
 value as there are enough occurrences of the pattern in Core that it could
 be worthwhile (18, based on a quick check).

 Something along the lines of:

 {{{#!php
 <?php
 wp_cache_get_query( ... $group ...) {
    $query_group = "$group-queries";
    $result = wp_cache_get( ... $query_group ... )
    $last_changed = wp_cache_get_last_changed( $group );
    if ( $result['last_changed'] !== $last_changed ) {
        return $false;
    }
    return $result['data'];
 }

 wp_cache_set_query( ... $group ... ) {
    $last_changed = wp_cache_get_last_changed( $group );
    wp_cache_set( $key, [ 'data' => $data, 'last_chagned' => $last_changed
 ], $group-queries )
 }
 }}}

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Ticket URL: <https://core.trac.wordpress.org/ticket/59592#comment:22>
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