BUGFIX: rewrote query for new games

old code used a long time to figure out if cards from another game could be reused. The new version should be much faster.

1 files changed, 12 insertions, 7 deletions

diff --git a/include/db.php b/include/db.php
index de549a5..e5699f6 100644
--- a/include/db.php
+++ b/include/db.php
@@ -786,13 +786,18 @@ function DB_get_email_pref_by_uid($uid)
 
 function DB_get_unused_randomnumbers($userstr)
 {
-  $r = DB_query_array(" SELECT randomnumbers FROM Game".
-		      "   WHERE randomnumbers NOT IN".
-		      "           (SELECT randomnumbers FROM Game".
-		      "                LEFT JOIN Hand ON Game.id=Hand.game_id".
-		      "                WHERE user_id IN  (". $userstr .")".
-		      "                GROUP BY randomnumbers".
-		      "           )");
+  /* optimized version of this query using temporary tables (perhaps we should use a procedure here?).
+     First we create a copy of the Game table using just the gameid and the cards.
+     Then in a second round we delete all the gameids of games where our players are in.
+     At the end we return only the first entry in the temporary table.
+  */
+  DB_query("DROP   TEMPORARY TABLE IF EXISTS gametmp;");
+  DB_query("CREATE TEMPORARY TABLE gametmp SELECT id,randomnumbers FROM Game;");
+  DB_query("DELETE FROM gametmp WHERE id IN (SELECT game_id FROM Hand WHERE user_id IN (".$userstr."));");
+
+  $r = DB_query_array("SELECT randomnumbers FROM gametmp LIMIT 1;");
+  DB_query("DROP   TEMPORARY TABLE IF EXISTS gametmp;");
+
   if($r)
     return $r[0];
   else