diff --git a/src/cluster/Backend.cc b/src/cluster/Backend.cc
index 675fcd7982..575d0aeaf7 100644
--- a/src/cluster/Backend.cc
+++ b/src/cluster/Backend.cc
@@ -203,6 +203,7 @@ bool ThreadedBackend::DoInit() {
 
 void ThreadedBackend::DoTerminate() {
     if ( onloop ) {
+        onloop->Process();
         onloop->Close();
         onloop = nullptr;
     }
diff --git a/src/cluster/Backend.h b/src/cluster/Backend.h
index 8c40e29703..1b09fb4c88 100644
--- a/src/cluster/Backend.h
+++ b/src/cluster/Backend.h
@@ -564,7 +564,8 @@ protected:
     /**
      * To be used by implementations to enqueue messages for processing on the IO loop.
      *
-     * It's safe to call this method from any thread.
+     * It's safe to call this method from any thread before ThreadedBackend's
+     * DoTerminate() implementation is invoked.
      *
      * @param messages Messages to be enqueued.
      */
@@ -582,6 +583,17 @@ protected:
      */
     bool DoInit() override;
 
+    /**
+     * Common DoTerminate() functionality for threaded backends.
+     *
+     * The default DoTerminate() implementation of ThreadedBackend
+     * runs OnLoop's Process() once to drain any pending messages, then
+     * closes and unsets it.
+     *
+     * Classes deriving from ThreadedBackend need to ensure that all threads
+     * calling QeueuForProcessing() have terminated before invoking the
+     * ThreadedBackend's DoTerminate() implementation.
+     */
     void DoTerminate() override;
 
 private: