Index: modules/block/block.admin.inc
===================================================================
RCS file: /cvs/drupal/drupal/modules/block/block.admin.inc,v
retrieving revision 1.63
diff -u -p -r1.63 block.admin.inc
--- modules/block/block.admin.inc	19 Nov 2009 04:00:47 -0000	1.63
+++ modules/block/block.admin.inc	30 Nov 2009 08:15:55 -0000
@@ -423,6 +423,7 @@ function block_admin_configure_submit($f
     module_invoke($form_state['values']['module'], 'block_save', $form_state['values']['delta'], $form_state['values']);
     drupal_set_message(t('The block configuration has been saved.'));
     cache_clear_all();
+    cache_clear_all('block_info_alter', 'cache_bootstrap');
     $form_state['redirect'] = 'admin/structure/block';
   }
 }
Index: modules/block/block.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/block/block.module,v
retrieving revision 1.400
diff -u -p -r1.400 block.module
--- modules/block/block.module	22 Nov 2009 21:24:37 -0000	1.400
+++ modules/block/block.module	30 Nov 2009 08:15:55 -0000
@@ -658,18 +658,25 @@ function _block_load_blocks() {
 function block_block_info_alter(&$blocks) {
   global $user, $theme_key;
 
-  // Build an array of roles for each block.
-  $block_roles = array();
-  $result = db_query('SELECT module, delta, rid FROM {block_role}');
-  foreach ($result as $record) {
-    $block_roles[$record->module][$record->delta][] = $record->rid;
+  if ($cached = cache_get('block_info_alter', 'cache_bootstrap')) {
+    $block_roles = $cached->data['roles'];
+    $block_node_types = $cached->data['node_types'];
   }
+  else {
+    // Build an array of roles for each block.
+    $block_roles = array();
+    $result = db_query('SELECT module, delta, rid FROM {block_role}');
+    foreach ($result as $record) {
+      $block_roles[$record->module][$record->delta][] = $record->rid;
+    }
 
-  // Build an array of node types for each block.
-  $block_node_types = array();
-  $result = db_query('SELECT module, delta, type FROM {block_node_type}');
-  foreach ($result as $record) {
-    $block_node_types[$record->module][$record->delta][] = $record->type;
+    // Build an array of node types for each block.
+    $block_node_types = array();
+    $result = db_query('SELECT module, delta, type FROM {block_node_type}');
+    foreach ($result as $record) {
+      $block_node_types[$record->module][$record->delta][] = $record->type;
+    }
+    cache_set('block_info_alter', array('roles' => $block_roles, 'node_types' => $block_node_types), 'cache_bootstrap');
   }
 
   foreach ($blocks as $key => $block) {