Add comment about why we pick a random number in PHP and use it as a

literal constant instead of the RAND() function. Also removed wfLocalUrl().

diff --git a/includes/SpecialRandompage.php b/includes/SpecialRandompage.php
index 9282de8..a8c5ed3 100644 (file)
--- a/includes/SpecialRandompage.php
+++ b/includes/SpecialRandompage.php
@@ -12,9 +12,19 @@ function wfSpecialRandompage() {
        global $wgOut, $wgTitle, $wgArticle, $wgExtraRandompageSQL;
        $fname = 'wfSpecialRandompage';
 
+       # NOTE! We use a literal constant in the SQL instead of the RAND()
+       # function because RAND() will return a different value for every row
+       # in the table. That's both very slow and returns results heavily
+       # biased towards low values, as rows later in the table will likely
+       # never be reached for comparison.
+       #
+       # Using a literal constant means the whole thing gets optimized on
+       # the index, and the comparison is both fast and fair.
        $rand = mt_rand() / mt_getrandmax();
+       
        # interpolation and sprintf() can muck up with locale-specific decimal separator
        $randstr = number_format( $rand, 12, ".", "" );
+       
        $db =& wfGetDB( DB_SLAVE );
        $use_index = $db->useIndexClause( 'cur_random' );
        $cur = $db->tableName( 'cur' );
@@ -31,15 +41,17 @@ function wfSpecialRandompage() {
                ORDER BY cur_random
                LIMIT 1";
        $res = $db->query( $sqlget, $fname );
+       
+       $title = null;
        if( $s = $db->fetchObject( $res ) ) {
-               $rt = wfUrlEncode( $s->cur_title );
-       } else {
-               # No articles?!
-               $rt = "";
+               $title =& Title::makeTitle( NS_MAIN, $s->cur_title );
+       }       
+       if( is_null( $title ) ) {
+               # That's not supposed to happen :)
+               $title =& Title::newFromText( wfMsg( 'mainpage' ) );
        }
-
        $wgOut->reportTime(); # for logfile
-       $wgOut->redirect( wfLocalUrl( $rt ) );
+       $wgOut->redirect( $title->getFullUrl() );
 }
 
 ?>