Adjust Shortpages query with multiple content namespaces

MariaDB can't effectively use the page_redirect_namespace_len index when
there are multiple namespaces. Instead, let's query each namespace
individually and UNION them together.

Bug: T168010
Change-Id: I632fbc599e06a3c2faabd55f5d87339f968f58bb

diff --git a/includes/specials/SpecialShortpages.php b/includes/specials/SpecialShortpages.php
index 3282a7a..f980e71 100644 (file)
--- a/includes/specials/SpecialShortpages.php
+++ b/includes/specials/SpecialShortpages.php
@@ -65,6 +65,57 @@ class ShortPagesPage extends QueryPage {
                ];
        }
 
+       public function reallyDoQuery( $limit, $offset = false ) {
+               $fname = static::class . '::reallyDoQuery';
+               $dbr = $this->getRecacheDB();
+               $query = $this->getQueryInfo();
+               $order = $this->getOrderFields();
+
+               if ( $this->sortDescending() ) {
+                       foreach ( $order as &$field ) {
+                               $field .= ' DESC';
+                       }
+               }
+
+               $tables = isset( $query['tables'] ) ? (array)$query['tables'] : [];
+               $fields = isset( $query['fields'] ) ? (array)$query['fields'] : [];
+               $conds = isset( $query['conds'] ) ? (array)$query['conds'] : [];
+               $options = isset( $query['options'] ) ? (array)$query['options'] : [];
+               $join_conds = isset( $query['join_conds'] ) ? (array)$query['join_conds'] : [];
+
+               if ( $limit !== false ) {
+                       $options['LIMIT'] = intval( $limit );
+               }
+
+               if ( $offset !== false ) {
+                       $options['OFFSET'] = intval( $offset );
+               }
+
+               $namespaces = $conds['page_namespace'];
+               if ( count( $namespaces ) === 1 ) {
+                       $options['ORDER BY'] = $order;
+                       $res = $dbr->select( $tables, $fields, $conds, $fname,
+                               $options, $join_conds
+                       );
+               } else {
+                       unset( $conds['page_namespace'] );
+                       $options['INNER ORDER BY'] = $order;
+                       $options['ORDER BY'] = [ 'value' . ( $this->sortDescending() ? ' DESC' : '' ) ];
+                       $sql = $dbr->unionConditionPermutations(
+                               $tables,
+                               $fields,
+                               [ 'page_namespace' => $namespaces ],
+                               $conds,
+                               $fname,
+                               $options,
+                               $join_conds
+                       );
+                       $res = $dbr->query( $sql, $fname );
+               }
+
+               return $res;
+       }
+
        function getOrderFields() {
                return [ 'page_len' ];
        }