From 53ebddfa9fbd031a99a269a71655acb6a96639eb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Miroslav=20Bajto=C5=A1?= <miroslav@strongloop.com>
Date: Tue, 3 Mar 2015 12:00:47 +0100
Subject: [PATCH] Create a remote checkpoint during replication too

Before this change, in the case of a one-way replication, the remote
checkpoint was never updated, thus the "diff" step had to check
all changes made through the whole history.

This commit fixes the problem by creating a new remote checkpoint
at the same time when a local checkpoint is created.

It is important to create the new checkpoint before the replication is
started to prevent a race condition where a remote change can end up
being associated with an already replicated checkpoint.
---
 lib/persisted-model.js | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/lib/persisted-model.js b/lib/persisted-model.js
index 8dfe82c9..0062a64b 100644
--- a/lib/persisted-model.js
+++ b/lib/persisted-model.js
@@ -855,7 +855,7 @@ PersistedModel.replicate = function(since, targetModel, options, callback) {
   };
 
   var tasks = [
-    checkpoint,
+    checkpoints,
     getSourceChanges,
     getDiffFromTarget,
     createSourceUpdates,
@@ -887,9 +887,13 @@ PersistedModel.replicate = function(since, targetModel, options, callback) {
     targetModel.bulkUpdate(updates, cb);
   }
 
-  function checkpoint() {
+  function checkpoints() {
     var cb = arguments[arguments.length - 1];
-    sourceModel.checkpoint(function(err) { cb(err); });
+    sourceModel.checkpoint(function(err) {
+      targetModel.checkpoint(function(err) {
+        cb(err);
+      });
+    });
   }
 
   function done(err) {