diff --git a/resources/sql/autopatches/20141123.taskpriority.1.sql b/resources/sql/autopatches/20141123.taskpriority.1.sql
new file mode 100644
--- /dev/null
+++ b/resources/sql/autopatches/20141123.taskpriority.1.sql
@@ -0,0 +1,2 @@
+UPDATE {$NAMESPACE}_worker.worker_activetask
+  SET priority = 5000 - priority;
diff --git a/resources/sql/autopatches/20141123.taskpriority.2.sql b/resources/sql/autopatches/20141123.taskpriority.2.sql
new file mode 100644
--- /dev/null
+++ b/resources/sql/autopatches/20141123.taskpriority.2.sql
@@ -0,0 +1,2 @@
+UPDATE {$NAMESPACE}_worker.worker_archivetask
+  SET priority = 5000 - priority;
diff --git a/src/infrastructure/daemon/workers/PhabricatorWorker.php b/src/infrastructure/daemon/workers/PhabricatorWorker.php
--- a/src/infrastructure/daemon/workers/PhabricatorWorker.php
+++ b/src/infrastructure/daemon/workers/PhabricatorWorker.php
@@ -9,10 +9,14 @@
   private static $runAllTasksInProcess = false;
   private $queuedTasks = array();
 
-  const PRIORITY_ALERTS  = 4000;
-  const PRIORITY_DEFAULT = 3000;
-  const PRIORITY_BULK    = 2000;
-  const PRIORITY_IMPORT  = 1000;
+  // NOTE: Lower priority numbers execute first. The priority numbers have to
+  // have the same ordering that IDs do (lowest first) so MySQL can use a
+  // multipart key across both of them efficiently.
+
+  const PRIORITY_ALERTS  = 1000;
+  const PRIORITY_DEFAULT = 2000;
+  const PRIORITY_BULK    = 3000;
+  const PRIORITY_IMPORT  = 4000;
 
 
 /* -(  Configuring Retries and Failures  )----------------------------------- */
diff --git a/src/infrastructure/daemon/workers/__tests__/PhabricatorWorkerTestCase.php b/src/infrastructure/daemon/workers/__tests__/PhabricatorWorkerTestCase.php
--- a/src/infrastructure/daemon/workers/__tests__/PhabricatorWorkerTestCase.php
+++ b/src/infrastructure/daemon/workers/__tests__/PhabricatorWorkerTestCase.php
@@ -160,14 +160,14 @@
     $this->expectNextLease($task1);
   }
 
-  public function testLeasedIsHighestPriority() {
-    $task1 = $this->scheduleTask(array(), 1);
-    $task2 = $this->scheduleTask(array(), 1);
-    $task3 = $this->scheduleTask(array(), 2);
+  public function testLeasedIsLowestPriority() {
+    $task1 = $this->scheduleTask(array(), 2);
+    $task2 = $this->scheduleTask(array(), 2);
+    $task3 = $this->scheduleTask(array(), 1);
 
     $this->expectNextLease(
       $task3,
-      'Tasks with a higher priority should be scheduled first.');
+      'Tasks with a lower priority should be scheduled first.');
     $this->expectNextLease(
       $task1,
       'Tasks with the same priority should be FIFO.');
diff --git a/src/infrastructure/daemon/workers/query/PhabricatorWorkerLeaseQuery.php b/src/infrastructure/daemon/workers/query/PhabricatorWorkerLeaseQuery.php
--- a/src/infrastructure/daemon/workers/query/PhabricatorWorkerLeaseQuery.php
+++ b/src/infrastructure/daemon/workers/query/PhabricatorWorkerLeaseQuery.php
@@ -215,8 +215,8 @@
     switch ($phase) {
       case self::PHASE_UNLEASED:
         // When selecting new tasks, we want to consume them in order of
-        // decreasing priority (and then FIFO).
-        return qsprintf($conn_w, 'ORDER BY priority DESC, id ASC');
+        // increasing priority (and then FIFO).
+        return qsprintf($conn_w, 'ORDER BY priority ASC, id ASC');
       case self::PHASE_EXPIRED:
         // When selecting failed tasks, we want to consume them in roughly
         // FIFO order of their failures, which is not necessarily their original