only save a checkpoint at the end if something changed

git-svn-id: https://svn.apache.org/repos/asf/couchdb/trunk@807360 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 42 insertions, 36 deletions

diff --git a/src/couchdb/couch_rep.erl b/src/couchdb/couch_rep.erl
index 9107918c..41b3cea2 100644
--- a/src/couchdb/couch_rep.erl
+++ b/src/couchdb/couch_rep.erl
@@ -171,6 +171,7 @@ handle_info({missing_revs_checkpoint, SourceSeq}, State) ->
 
 handle_info({writer_checkpoint, SourceSeq}, #state{committed_seq=N} = State)
         when SourceSeq > N ->
+    ?LOG_DEBUG("SourceSeq ~p N ~p", [SourceSeq, N]),
     MissingRevs = State#state.missing_revs,
     ok = gen_server:cast(MissingRevs, {update_committed_seq, SourceSeq}),
     couch_task_status:update("W Processed source update #~p", [SourceSeq]),
@@ -196,43 +197,12 @@ handle_info({'EXIT', Pid, Reason}, State) ->
     ?LOG_ERROR("exit of linked Pid ~p with reason ~p", [Pid, Reason]),
     {stop, Reason, State}.
 
-terminate(normal, State) ->
-    #state{
-        checkpoint_scheduled = TRef,
-        checkpoint_history = CheckpointHistory,
-        committed_seq = NewSeq,
-        listeners = Listeners,
-        source = Source,
-        target = Target,
-        stats = Stats,
-        source_log = #doc{body={OldHistory}}
-    } = do_checkpoint(State),
-    timer:cancel(TRef),
-    couch_task_status:update("Finishing"),
-    ets:delete(Stats),
-    close_db(Target),
+terminate(normal, #state{checkpoint_scheduled=nil} = State) ->
+    do_terminate(State);
     
-    NewRepHistory = case CheckpointHistory of
-    nil ->
-        {[{<<"no_changes">>, true} | OldHistory]};
-    _Else ->
-        CheckpointHistory
-    end,
-
-    %% reply to original requester
-    [Original|OtherListeners] = lists:reverse(Listeners),
-    gen_server:reply(Original, {ok, NewRepHistory}),
-
-    %% maybe trigger another replication. If this replicator uses a local
-    %% source Db, changes to that Db since we started will not be included in
-    %% this pass.
-    case up_to_date(Source, NewSeq) of
-        true ->
-            [gen_server:reply(R, {ok, NewRepHistory}) || R <- OtherListeners];
-        false ->
-            [gen_server:reply(R, retry) || R <- OtherListeners]
-    end,
-    close_db(Source);
+terminate(normal, State) ->
+    timer:cancel(State#state.checkpoint_scheduled),
+    do_terminate(do_checkpoint(State));
 
 terminate(Reason, State) ->
     #state{
@@ -340,6 +310,42 @@ dbinfo(Db) ->
     {ok, Info} = couch_db:get_db_info(Db),
     Info.
 
+do_terminate(State) ->
+    #state{
+        checkpoint_history = CheckpointHistory,
+        committed_seq = NewSeq,
+        listeners = Listeners,
+        source = Source,
+        target = Target,
+        stats = Stats,
+        source_log = #doc{body={OldHistory}}
+    } = State,
+    couch_task_status:update("Finishing"),
+    ets:delete(Stats),
+    close_db(Target),
+    
+    NewRepHistory = case CheckpointHistory of
+    nil ->
+        {[{<<"no_changes">>, true} | OldHistory]};
+    _Else ->
+        CheckpointHistory
+    end,
+
+    %% reply to original requester
+    [Original|OtherListeners] = lists:reverse(Listeners),
+    gen_server:reply(Original, {ok, NewRepHistory}),
+
+    %% maybe trigger another replication. If this replicator uses a local
+    %% source Db, changes to that Db since we started will not be included in
+    %% this pass.
+    case up_to_date(Source, NewSeq) of
+        true ->
+            [gen_server:reply(R, {ok, NewRepHistory}) || R <- OtherListeners];
+        false ->
+            [gen_server:reply(R, retry) || R <- OtherListeners]
+    end,
+    close_db(Source).
+
 has_session_id(_SessionId, []) ->
     false;
 has_session_id(SessionId, [{Props} | Rest]) ->