Index: includes/common.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/common.inc,v
retrieving revision 1.756.2.107
diff -u -p -r1.756.2.107 common.inc
--- includes/common.inc	15 Dec 2010 21:34:35 -0000	1.756.2.107
+++ includes/common.inc	29 Dec 2010 04:17:51 -0000
@@ -3259,29 +3259,39 @@ function drupal_common_theme() {
 function drupal_get_schema($table = NULL, $rebuild = FALSE) {
   static $schema = array();
 
-  if (empty($schema) || $rebuild) {
-    // Try to load the schema from cache.
-    if (!$rebuild && $cached = cache_get('schema')) {
-      $schema = $cached->data;
+  // If a table is specified, try to load the individual cache entry for that
+  // table.
+  if (isset($table) && !$rebuild) {
+    if (isset($schema[$table])) {
+      return $schema[$table];
+    }
+    else if ($cached = cache_get('schema:' . $table)) {
+      $schema[$table] = $cached->data;
     }
-    // Otherwise, rebuild the schema cache.
     else {
-      $schema = array();
-      // Load the .install files to get hook_schema.
-      module_load_all_includes('install');
-
-      // Invoke hook_schema for all modules.
-      foreach (module_implements('schema') as $module) {
-        // Cast the result of hook_schema() to an array, as a NULL return value
-        // would cause array_merge() to set the $schema variable to NULL as well.
-        // That would break modules which use $schema further down the line.
-        $current = (array) module_invoke($module, 'schema');
-        _drupal_initialize_schema($module, $current);
-        $schema = array_merge($schema, $current);
+      $rebuild = TRUE;
+    }
+  }
+  if (!isset($table) || $rebuild) {
+    $schema = array();
+    // Load the .install files to get hook_schema.
+    module_load_all_includes('install');
+
+    // Invoke hook_schema for all modules.
+    foreach (module_implements('schema') as $module) {
+      // Cast the result of hook_schema() to an array, as a NULL return value
+      // would cause array_merge() to set the $schema variable to NULL as well.
+      // That would break modules which use $schema further down the line.
+      $current = (array) module_invoke($module, 'schema');
+      _drupal_initialize_schema($module, $current);
+      $schema = array_merge($schema, $current);
+    }
+
+    drupal_alter('schema', $schema);
+    if ($rebuild && !empty($schema)) {
+      foreach ($schema as $key => $definition) {
+        cache_set('schema:' . $key, $definition);
       }
-
-      drupal_alter('schema', $schema);
-      cache_set('schema', $schema);
     }
   }