Index: modules/system/system.install
===================================================================
RCS file: /cvs/drupal/drupal/modules/system/system.install,v
retrieving revision 1.57
diff -u -r1.57 system.install
--- modules/system/system.install	8 Dec 2006 16:13:42 -0000	1.57
+++ modules/system/system.install	9 Dec 2006 15:41:58 -0000
@@ -530,6 +530,7 @@
       db_query("CREATE TABLE {variable} (
         name varchar(48) NOT NULL default '',
         value longtext NOT NULL,
+        prefetch tinyint NOT NULL default '0',
         PRIMARY KEY (name)
       ) /*!40100 DEFAULT CHARACTER SET UTF8 */ ");
 
Index: includes/bootstrap.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/bootstrap.inc,v
retrieving revision 1.136
diff -u -r1.136 bootstrap.inc
--- includes/bootstrap.inc	8 Dec 2006 12:09:54 -0000	1.136
+++ includes/bootstrap.inc	9 Dec 2006 20:43:36 -0000
@@ -294,6 +294,9 @@
  * The variable table is composed of values that have been saved in the table
  * with variable_set() as well as those explicitly specified in the configuration
  * file.
+ *
+ * Only variables marked on variable_set as prefetchable are loaded here
+ * to avoid $conf cluttering
  */
 function variable_init($conf = array()) {
   // NOTE: caching the variables improves performance by 20% when serving cached pages.
@@ -301,7 +304,7 @@
     $variables = unserialize($cached->data);
   }
   else {
-    $result = db_query('SELECT * FROM {variable}');
+    $result = db_query('SELECT * FROM {variable} v WHERE v.prefetch = 1');
     while ($variable = db_fetch_object($result)) {
       $variables[$variable->name] = unserialize($variable->value);
     }
@@ -328,7 +331,16 @@
 function variable_get($name, $default) {
   global $conf;
 
-  return isset($conf[$name]) ? $conf[$name] : $default;
+  if (isset($conf[$name])) {
+    $variable = $conf[$name];
+  }
+  else {
+    /* cannot rely on db_result returning FALSE: this can be a valid result */
+    $o = db_fetch_object(db_query("SELECT value FROM {variable} WHERE name='%s'", $name));
+    $variable = isset($o) ? unserialize($o->value): $default;
+    $conf[$name] = $variable;
+  }
+  return $variable;
 }
 
 /**
@@ -339,13 +351,18 @@
  * @param $value
  *   The value to set. This can be any PHP data type; these functions take care
  *   of serialization as necessary.
+ * @param $prefetch
+ *   Is this variable to be loaded during variable_init ? Defaults to 1
+ *   as this is the standard behaviour in earlier Drupal versions. If set to 0,
+ *   variable will not be prefetched but will still be cached when retrieved
+ *   using variable_get
  */
-function variable_set($name, $value) {
+function variable_set($name, $value, $prefetch = 1) {
   global $conf;
 
   db_lock_table('variable');
   db_query("DELETE FROM {variable} WHERE name = '%s'", $name);
-  db_query("INSERT INTO {variable} (name, value) VALUES ('%s', '%s')", $name, serialize($value));
+  db_query("INSERT INTO {variable} (name, value, prefetch) VALUES ('%s', '%s', %d)", $name, serialize($value), $prefetch);
   db_unlock_tables();
 
   cache_clear_all('variables', 'cache');