Ticket #16706: 16706.2.diff

wp-includes/taxonomy.php

@@ -636 +636 @@
                 $where = array();
                 $i = 0;
 
-                foreach ( $this->queries as $query ) {
+                // convert AND queries to IN ones for more efficient SQL
+                if ( 'AND' == $this->relation ) {
+                        $final_queries = array();
+                        foreach ( $this->queries as $query ) {
+                                if ( 'AND' == $query['operator'] && count( $query['terms'] ) <= 10 ) {
+                                        foreach ( $query['terms'] as $term ) {
+                                                $final_queries[] = array_merge( $query, array(
+                                                        'terms' => $term,
+                                                        'operator' => 'IN'
+                                                ) );
+                                        }
+                                } else {
+                                        $final_queries[] = $query;
+                                }
+                        }
+                } else {
+                        $final_queries = $this->queries;
+                }
+
+                foreach ( $final_queries as $query ) {
                         $this->clean_query( $query );
 
                         if ( is_wp_error( $query ) ) {