--- a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/middleware/Crypto5MiddlewareRepositorySession.java
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/middleware/Crypto5MiddlewareRepositorySession.java
@@ -110,16 +110,21 @@ public class Crypto5MiddlewareRepository
     }
 
     @Override
     public void onFetchCompleted(final long fetchEnd) {
       next.onFetchCompleted(fetchEnd);
     }
 
     @Override
+    public void onBatchCompleted() {
+      next.onBatchCompleted();
+    }
+
+    @Override
     public RepositorySessionFetchRecordsDelegate deferredFetchDelegate(ExecutorService executor) {
       // Synchronously perform *our* work, passing through appropriately.
       RepositorySessionFetchRecordsDelegate deferredNext = next.deferredFetchDelegate(executor);
       return new DecryptingTransformingFetchDelegate(deferredNext, keyBundle, recordFactory);
     }
   }
 
   private DecryptingTransformingFetchDelegate makeUnwrappingDelegate(RepositorySessionFetchRecordsDelegate inner) {

--- a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/DeferredRepositorySessionFetchRecordsDelegate.java
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/DeferredRepositorySessionFetchRecordsDelegate.java
@@ -42,15 +42,25 @@ public class DeferredRepositorySessionFe
       @Override
       public void run() {
         inner.onFetchCompleted(fetchEnd);
       }
     });
   }
 
   @Override
+  public void onBatchCompleted() {
+    executor.execute(new Runnable() {
+      @Override
+      public void run() {
+        inner.onBatchCompleted();
+      }
+    });
+  }
+
+  @Override
   public RepositorySessionFetchRecordsDelegate deferredFetchDelegate(ExecutorService newExecutor) {
     if (newExecutor == executor) {
       return this;
     }
     throw new IllegalArgumentException("Can't re-defer this delegate.");
   }
 }

--- a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/RepositorySessionFetchRecordsDelegate.java
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/delegates/RepositorySessionFetchRecordsDelegate.java
@@ -18,10 +18,16 @@ public interface RepositorySessionFetchR
    * @param fetchEnd
    *        A millisecond-resolution timestamp indicating the *remote* timestamp
    *        at the end of the range of records. Usually this is the timestamp at
    *        which the request was received.
    *        E.g., the (normalized) value of the X-Weave-Timestamp header.
    */
   public void onFetchCompleted(final long fetchEnd);
 
-  public RepositorySessionFetchRecordsDelegate deferredFetchDelegate(ExecutorService executor);
+  /**
+   * Called when a number of records have been returned but more are still expected to come,
+   * possibly after a certain pause.
+   */
+  void onBatchCompleted();
+
+  RepositorySessionFetchRecordsDelegate deferredFetchDelegate(ExecutorService executor);
 }

--- a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/RecordsChannel.java
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/RecordsChannel.java
@@ -212,16 +212,20 @@ public class RecordsChannel implements
   public void onFetchCompleted(final long fetchEnd) {
     Logger.trace(LOG_TAG, "onFetchCompleted. Stopping consumer once stores are done.");
     Logger.trace(LOG_TAG, "Fetch timestamp is " + fetchEnd);
     this.fetchEnd = fetchEnd;
     this.consumer.queueFilled();
   }
 
   @Override
+  public void onBatchCompleted() {
+  }
+
+  @Override
   public void onRecordStoreFailed(Exception ex, String recordGuid) {
     Logger.trace(LOG_TAG, "Failed to store record with guid " + recordGuid);
     numStoreFailed.incrementAndGet();
     this.consumer.stored();
     delegate.onFlowStoreFailed(this, ex, recordGuid);
     // TODO: abort?
   }
 

--- a/mobile/android/tests/background/junit3/src/org/mozilla/gecko/background/db/TestBookmarks.java
+++ b/mobile/android/tests/background/junit3/src/org/mozilla/gecko/background/db/TestBookmarks.java
@@ -660,16 +660,21 @@ public class TestBookmarks extends Andro
         public void onFetchedRecord(Record record) {
           fetchedGUIDs.add(record.guid);
         }
 
         @Override
         public void onFetchCompleted(long end) {
           finishAndNotify(session);
         }
+
+        @Override
+        public void onBatchCompleted() {
+
+        }
       };
       session.fetchSince(0, fetchDelegate);
     }
   }
 
   /**
    * Simple helper class for fetching a single record by GUID.
    * The fetched record is stored in `fetchedRecord`.
@@ -690,16 +695,21 @@ public class TestBookmarks extends Andro
         public void onFetchedRecord(Record record) {
           fetchedRecord = record;
         }
 
         @Override
         public void onFetchCompleted(long end) {
           finishAndNotify(session);
         }
+
+        @Override
+        public void onBatchCompleted() {
+
+        }
       };
       try {
         session.fetch(new String[] { guid }, fetchDelegate);
       } catch (InactiveSessionException e) {
         performNotify("Session is inactive.", e);
       }
     }
   }

--- a/mobile/android/tests/background/junit3/src/org/mozilla/gecko/background/sync/TestStoreTracking.java
+++ b/mobile/android/tests/background/junit3/src/org/mozilla/gecko/background/sync/TestStoreTracking.java
@@ -99,18 +99,28 @@ public class TestStoreTracking extends A
                                                     RepositorySessionBundle bundle) {
                         performNotify();
                       }
                     });
                   } catch (InactiveSessionException e) {
                     performNotify(e);
                   }
                 }
+
+                @Override
+                public void onBatchCompleted() {
+
+                }
               });
             }
+
+            @Override
+            public void onBatchCompleted() {
+
+            }
           });
         } catch (InactiveSessionException e) {
           performNotify(e);
         }
       }
     };
 
     session.setStoreDelegate(storeDelegate);
@@ -151,16 +161,21 @@ public class TestStoreTracking extends A
                         // Hooray!
                         performNotify();
                       }
                     });
                   } catch (InactiveSessionException e) {
                     performNotify(e);
                   }
                 }
+
+                @Override
+                public void onBatchCompleted() {
+
+                }
               });
             }
           });
         } catch (InvalidSessionTransitionException e) {
           performNotify(e);
         }
       }
     };

--- a/mobile/android/tests/background/junit3/src/org/mozilla/gecko/background/sync/helpers/DefaultFetchDelegate.java
+++ b/mobile/android/tests/background/junit3/src/org/mozilla/gecko/background/sync/helpers/DefaultFetchDelegate.java
@@ -95,12 +95,17 @@ public class DefaultFetchDelegate extend
   }
 
   @Override
   public void onFetchCompleted(final long fetchEnd) {
     Logger.debug(LOG_TAG, "onFetchCompleted. Doing nothing.");
   }
 
   @Override
+  public void onBatchCompleted() {
+    Logger.debug(LOG_TAG, "onBatchCompleted. Doing nothing.");
+  }
+
+  @Override
   public RepositorySessionFetchRecordsDelegate deferredFetchDelegate(final ExecutorService executor) {
     return new DeferredRepositorySessionFetchRecordsDelegate(this, executor);
   }
 }

--- a/mobile/android/tests/background/junit4/src/org/mozilla/android/sync/test/SynchronizerHelpers.java
+++ b/mobile/android/tests/background/junit4/src/org/mozilla/android/sync/test/SynchronizerHelpers.java
@@ -50,16 +50,21 @@ public class SynchronizerHelpers {
             }
 
             @Override
             public void onFetchCompleted(long fetchEnd) {
               delegate.onFetchCompleted(fetchEnd);
             }
 
             @Override
+            public void onBatchCompleted() {
+
+            }
+
+            @Override
             public RepositorySessionFetchRecordsDelegate deferredFetchDelegate(ExecutorService executor) {
               return this;
             }
           });
         }
       });
     }
   }

--- a/mobile/android/tests/background/junit4/src/org/mozilla/android/sync/test/helpers/ExpectSuccessRepositorySessionFetchRecordsDelegate.java
+++ b/mobile/android/tests/background/junit4/src/org/mozilla/android/sync/test/helpers/ExpectSuccessRepositorySessionFetchRecordsDelegate.java
@@ -33,12 +33,17 @@ public class ExpectSuccessRepositorySess
 
   @Override
   public void onFetchCompleted(long end) {
     log("Fetch completed.");
     performNotify();
   }
 
   @Override
+  public void onBatchCompleted() {
+    log("Batch completed.");
+  }
+
+  @Override
   public RepositorySessionFetchRecordsDelegate deferredFetchDelegate(ExecutorService executor) {
     return this;
   }
 }

--- a/mobile/android/tests/background/junit4/src/org/mozilla/gecko/sync/repositories/downloaders/BatchingDownloaderDelegateTest.java
+++ b/mobile/android/tests/background/junit4/src/org/mozilla/gecko/sync/repositories/downloaders/BatchingDownloaderDelegateTest.java
@@ -82,16 +82,21 @@ public class BatchingDownloaderDelegateT
         }
 
         @Override
         public void onFetchCompleted(long fetchEnd) {
 
         }
 
         @Override
+        public void onBatchCompleted() {
+
+        }
+
+        @Override
         public RepositorySessionFetchRecordsDelegate deferredFetchDelegate(ExecutorService executor) {
             return null;
         }
     }
 
     @Before
     public void setUp() throws Exception {
         server11Repository = new Server11Repository(

--- a/mobile/android/tests/background/junit4/src/org/mozilla/gecko/sync/repositories/downloaders/BatchingDownloaderTest.java
+++ b/mobile/android/tests/background/junit4/src/org/mozilla/gecko/sync/repositories/downloaders/BatchingDownloaderTest.java
@@ -47,16 +47,17 @@ public class BatchingDownloaderTest {
     private String DEFAULT_SORT = "index";
     private String DEFAULT_IDS = "1";
     private String DEFAULT_LMHEADER = "12345678";
 
     class MockSessionFetchRecordsDelegate implements RepositorySessionFetchRecordsDelegate {
         public boolean isFailure;
         public boolean isFetched;
         public boolean isSuccess;
+        public int batchesCompleted;
         public Exception ex;
         public Record record;
 
         @Override
         public void onFetchFailed(Exception ex, Record record) {
             this.isFailure = true;
             this.ex = ex;
             this.record = record;
@@ -69,16 +70,21 @@ public class BatchingDownloaderTest {
         }
 
         @Override
         public void onFetchCompleted(long fetchEnd) {
             this.isSuccess = true;
         }
 
         @Override
+        public void onBatchCompleted() {
+            this.batchesCompleted += 1;
+        }
+
+        @Override
         public RepositorySessionFetchRecordsDelegate deferredFetchDelegate(ExecutorService executor) {
             return null;
         }
     }
 
     class MockRequest extends SyncStorageCollectionRequest {
 
         public MockRequest(URI uri) {