Opened 13 years ago
Closed 13 years ago
#20236 closed defect (bug) (fixed)
Improper testing of cache retrievals causes wasted queries.
Reported by: |
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Owned by: | |
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Milestone: | 3.4 | Priority: | normal |
Severity: | normal | Version: | |
Component: | Cache API | Keywords: | has-patch |
Focuses: | Cc: |
Description
wp_cache_get()
can retrieve values such as the empty array which is considered false by the !
test. The following function is incorrect because it will always ignore the cache and repeat the get_col
and wp_cache_add
when the cache contains the empty array. This occurs on sites which have no pages.
function get_all_page_ids() { global $wpdb; if ( ! $page_ids = wp_cache_get('all_page_ids', 'posts') ) { $page_ids = $wpdb->get_col("SELECT ID FROM $wpdb->posts WHERE post_type = 'page'"); wp_cache_add('all_page_ids', $page_ids, 'posts'); } return $page_ids; }
The cache check should be written with an understanding of the return type of $wpdb->get_col()
(array). Here it is with the check fixed:
function get_all_page_ids() { global $wpdb; $page_ids = wp_cache_get('all_page_ids', 'posts'); if ( ! is_array( $page_ids ) ) { $page_ids = $wpdb->get_col("SELECT ID FROM $wpdb->posts WHERE post_type = 'page'"); wp_cache_add('all_page_ids', $page_ids, 'posts'); } return $page_ids; }
Patch 1 fixes this occurrence. Please keep this ticket open until all similar occurrences are found and fixed.
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Change History (5)
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fix get_all_page_ids()