Index: src/main/java/org/apache/jackrabbit/mongomk/impl/command/CommitCommand.java
===================================================================
--- src/main/java/org/apache/jackrabbit/mongomk/impl/command/CommitCommand.java	(revision 1439323)
+++ src/main/java/org/apache/jackrabbit/mongomk/impl/command/CommitCommand.java	(working copy)
@@ -97,13 +97,14 @@
             prepareCommit();
             readAndMergeExistingNodes();
             prepareMongoNodes();
-            new SaveNodesAction(nodeStore, nodes.values()).execute();
-            new SaveCommitAction(nodeStore, commit).execute();
-            success = saveAndSetHeadRevision();
+            success = saveNodesAndCommits();
             if (success) {
-                cacheNodes();
-            } else {
-                retries++;
+                success = saveAndSetHeadRevision();
+                if (success) {
+                    cacheNodes();
+                } else {
+                    retries++;
+                }
             }
         } while (!success);
 
@@ -115,6 +116,17 @@
         return revisionId;
     }
 
+    private boolean saveNodesAndCommits() throws Exception {
+        long headRevisionId = new FetchHeadRevisionIdAction(nodeStore, branchId).execute();
+        if (branchId == null && headRevisionId != mongoSync.getHeadRevisionId()) {
+            // Head revision moved on in trunk in the meantime, no need to save
+            return false;
+        }
+        new SaveNodesAction(nodeStore, nodes.values()).execute();
+        new SaveCommitAction(nodeStore, commit).execute();
+        return true;
+    }
+
     @Override
     public int getNumOfRetries() {
         return 100;
@@ -184,7 +196,6 @@
         }
     }
 
-
 //    private void readExistingNodes() {
 //        FetchNodesAction action = new FetchNodesAction(nodeStore, affectedPaths,
 //                mongoSync.getHeadRevisionId());