Added batching of multiple updating requests, to improve throughput with many writers. Also removed the couch_batch_save module, now batch requests are simply saved async as immediately, batching with outhr updates if possible.

git-svn-id: https://svn.apache.org/repos/asf/couchdb/trunk@832550 13f79535-47bb-0310-9956-ffa450edef68

7 files changed, 151 insertions, 385 deletions

diff --git a/src/couchdb/Makefile.am b/src/couchdb/Makefile.am
index 2459ca8f..5842521b 100644
--- a/src/couchdb/Makefile.am
+++ b/src/couchdb/Makefile.am
@@ -56,8 +56,6 @@ source_files = \
     couch.erl \
     couch_app.erl \
     couch_btree.erl \
-    couch_batch_save.erl \
-    couch_batch_save_sup.erl \
     couch_config.erl \
     couch_config_writer.erl \
     couch_db.erl \
@@ -113,8 +111,6 @@ compiled_files = \
     couch.beam \
     couch_app.beam \
     couch_btree.beam \
-    couch_batch_save.beam \
-    couch_batch_save_sup.beam \
     couch_config.beam \
     couch_config_writer.beam \
     couch_db.beam \
diff --git a/src/couchdb/couch.app.tpl.in b/src/couchdb/couch.app.tpl.in
index 84ac36ee..fa86d2ec 100644
--- a/src/couchdb/couch.app.tpl.in
+++ b/src/couchdb/couch.app.tpl.in
@@ -3,8 +3,6 @@
     {vsn, "@version@"},
     {modules, [@modules@]},
     {registered, [
-        couch_batch_save,
-        couch_batch_save_sup,
         couch_config,
         couch_db_update,
         couch_db_update_notifier_sup,
diff --git a/src/couchdb/couch_batch_save.erl b/src/couchdb/couch_batch_save.erl
deleted file mode 100644
index 600dd00e..00000000
--- a/src/couchdb/couch_batch_save.erl
+++ /dev/null
@@ -1,273 +0,0 @@
-% Licensed under the Apache License, Version 2.0 (the "License"); you may not
-% use this file except in compliance with the License. You may obtain a copy of
-% the License at
-%
-%   http://www.apache.org/licenses/LICENSE-2.0
-%
-% Unless required by applicable law or agreed to in writing, software
-% distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
-% WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
-% License for the specific language governing permissions and limitations under
-% the License.
-
--module(couch_batch_save).
-
--behaviour(gen_server).
-
-%% API
--export([start_link/2, eventually_save_doc/3, commit_now/2]).
-
-%% gen_server callbacks
--export([init/1, handle_call/3, handle_cast/2, handle_info/2,
-     terminate/2, code_change/3]).
-
--include("couch_db.hrl").
-
--record(batch_state, {
-    batch_size=1000,
-    batch_interval=1000
-    }).
-
-%%====================================================================
-%% API
-%%====================================================================
-%%--------------------------------------------------------------------
-%% Function: start_link() -> {ok,Pid} | ignore | {error,Error}
-%% Description: Starts the server
-%%--------------------------------------------------------------------
-start_link(BatchSize, BatchInterval) ->
-    gen_server:start_link({local, couch_batch_save}, ?MODULE, [BatchSize, BatchInterval], []).
-
-%%--------------------------------------------------------------------
-%% Function: commit_doc(Doc) -> committed
-%% Description: Puts the doc into the set to commit. Does not reply until
-%% the commit is complete.
-%%--------------------------------------------------------------------
-eventually_save_doc(DbName, Doc, UserCtx) ->
-    % find or create a process for the {DbName, UserCtx} pair
-    {ok, Pid} = batch_pid_for_db_and_user(DbName, UserCtx),
-    % hand it the document
-    ?LOG_DEBUG("sending doc to batch ~p",[Pid]),
-    ok = send_doc_to_batch(Pid, Doc).
-
-%%--------------------------------------------------------------------
-%% Function: commit_now(DbName) -> committed
-%% Description: Commits all docs for the DB. Does not reply until
-%% the commit is complete.
-%%--------------------------------------------------------------------
-commit_now(DbName, UserCtx) ->
-    % find the process for the {DbName, UserCtx} pair
-    {ok, Pid} = batch_pid_for_db_and_user(DbName, UserCtx, false),
-    case Pid of
-        none -> committed;
-        _Else ->
-            ok = send_commit(Pid),
-            committed
-    end.
-
-%%--------------------------------------------------------------------
-%% Function: commit_now() -> committed
-%% Description: Commits all docs for all DBs. Does not reply until
-%% the commit is complete.
-%%--------------------------------------------------------------------
-% commit_all() ->
-%     committed = gen_server:call(couch_batch_save, commit_now, infinity).
-%
-
-%%====================================================================
-%% gen_server callbacks
-%%====================================================================
-
-%%--------------------------------------------------------------------
-%% Function: init([BatchSize, BatchInterval]) -> {ok, State} |
-%%                         {ok, State, Timeout} |
-%%                         ignore               |
-%%                         {stop, Reason}
-%% Description: Initiates the server with the meanings
-%%--------------------------------------------------------------------
-init([BatchSize, BatchInterval]) ->
-    ets:new(couch_batch_save_by_db, [set, public, named_table]),
-    {ok, #batch_state{batch_size=BatchSize, batch_interval=BatchInterval}}.
-
-%%--------------------------------------------------------------------
-%% Function: %% handle_call(Request, From, State) -> {reply, Reply, State} |
-%%                                      {reply, Reply, State, Timeout} |
-%%                                      {noreply, State} |
-%%                                      {noreply, State, Timeout} |
-%%                                      {stop, Reason, Reply, State} |
-%%                                      {stop, Reason, State}
-%% Description: Handling call messages
-%%--------------------------------------------------------------------
-handle_call({make_pid, DbName, UserCtx}, _From, #batch_state{
-        batch_size=BatchSize,
-        batch_interval=BatchInterval
-    }=State) ->
-    % Create the pid in a serialized process.
-    % We checked before to see that we need the Pid, but the check is outside
-    % the gen_server for parellelism. We check again here to ensure we don't
-    % make a duplicate.
-    Resp = case ets:lookup(couch_batch_save_by_db, {DbName,UserCtx}) of
-        [{_, Pid}] ->
-            % we have a pid
-            {ok, Pid};
-        [] ->
-            % no match
-            % start and record the doc collector process
-            ?LOG_DEBUG("making a batch pid ~p",[{DbName, UserCtx}]),
-            Pid = spawn_link(fun() ->
-                doc_collector(DbName, UserCtx, {BatchSize, BatchInterval}, new)
-            end),
-            true = ets:insert_new(couch_batch_save_by_db, {{DbName, UserCtx}, Pid}),
-            {ok, Pid}
-    end,
-    {reply, Resp, State}.
-
-%%--------------------------------------------------------------------
-%% Function: handle_cast(Msg, State) -> {noreply, State} |
-%%                                      {noreply, State, Timeout} |
-%%                                      {stop, Reason, State}
-%% Description: Handling cast messages
-%%--------------------------------------------------------------------
-handle_cast(_Msg, State) ->
-    {noreply, State}.
-
-%%--------------------------------------------------------------------
-%% Function: handle_info(Info, State) -> {noreply, State} |
-%%                                       {noreply, State, Timeout} |
-%%                                       {stop, Reason, State}
-%% Description: Handling all non call/cast messages
-%%--------------------------------------------------------------------
-% handle_info({'EXIT', Pid, Reason}, State) ->
-%     {noreply, State};
-
-handle_info(_Info, State) ->
-    {noreply, State}.
-
-%%--------------------------------------------------------------------
-%% Function: terminate(Reason, State) -> void()
-%% Description: This function is called by a gen_server when it is about to
-%% terminate. It should be the opposite of Module:init/1 and do any necessary
-%% cleaning up. When it returns, the gen_server terminates with Reason.
-%% The return value is ignored.
-%%--------------------------------------------------------------------
-terminate(_Reason, _State) ->
-    % todo shutdown the interval loop
-    % todo kill all the Pids and drop the ets table
-    ok.
-
-%%--------------------------------------------------------------------
-%% Func: code_change(OldVsn, State, Extra) -> {ok, NewState}
-%% Description: Convert process state when code is changed
-%%--------------------------------------------------------------------
-code_change(_OldVsn, State, _Extra) ->
-    {ok, State}.
-
-%%--------------------------------------------------------------------
-%%% Internal functions
-%%--------------------------------------------------------------------
-
-commit_user_docs(_DbName, _UserCtx, []) ->
-    {ok, []};
-
-commit_user_docs(DbName, UserCtx, Docs) ->
-    ?LOG_INFO("Committing ~p batch docs to ~p",[length(Docs), DbName]),
-    case couch_db:open(DbName, [{user_ctx, UserCtx}]) of
-    {ok, Db} ->
-        try
-            {ok, Revs} = couch_db:update_docs(Db, Docs),
-            ?LOG_INFO("Committed ~p batch docs to ~p",[length(Docs), DbName]),
-            {ok, Revs}
-        after
-            couch_db:close(Db)
-        end;
-    Error ->
-        throw(Error)
-    end.
-
-% spawned to trigger commits on an interval
-commit_every_ms(Pid, BatchInterval) ->
-    receive
-        after BatchInterval ->
-            ok = send_commit(Pid),
-            commit_every_ms(Pid, BatchInterval)
-    end.
-
-send_commit(Pid) ->
-    Pid ! {self(), commit},
-    receive
-        {Pid, committed} ->
-           ok;
-        {'DOWN', _, _, Pid, _} ->
-           exit(normal)
-    end.
-
-batch_pid_for_db_and_user(DbName, UserCtx) ->
-    batch_pid_for_db_and_user(DbName, UserCtx, true).
-
-batch_pid_for_db_and_user(DbName, UserCtx, Create) ->
-    % look in the ets table
-    case ets:lookup(couch_batch_save_by_db, {DbName,UserCtx}) of
-        [{_, Pid}] ->
-            % we have a pid
-            {ok, Pid};
-        [] ->
-            % no match
-            if Create ->
-                {ok, Pid} = gen_server:call(couch_batch_save, {make_pid, DbName, UserCtx}, infinity),
-                {ok, Pid};
-            true ->
-                {ok, none}
-            end
-    end.
-
-send_doc_to_batch(Pid, Doc) ->
-    Pid ! {self(), add_doc, Doc},
-    receive
-        {Pid, doc_added} -> ok
-    end.
-
-% the loop that holds documents between commits
-doc_collector(DbName, UserCtx, {BatchSize, BatchInterval}, new) ->
-    % start a process that triggers commit every BatchInterval milliseconds
-    Me = self(),
-    spawn_link(fun() ->
-        erlang:monitor(process, Me),
-        commit_every_ms(Me, BatchInterval) 
-    end),
-    doc_collector(DbName, UserCtx, {BatchSize, BatchInterval}, []);
-
-doc_collector(DbName, UserCtx, {BatchSize, BatchInterval}, Docs) when length(Docs) >= BatchSize->
-    collector_commit(DbName, UserCtx, BatchInterval, Docs),
-    exit(normal);
-
-doc_collector(DbName, UserCtx, {BatchSize, BatchInterval}, Docs) ->
-    receive
-        {From, add_doc, Doc} ->
-            From ! {self(), doc_added},
-            doc_collector(DbName, UserCtx, {BatchSize, BatchInterval}, [Doc|Docs]);
-        {From, commit} ->
-            collector_commit(DbName, UserCtx, BatchInterval, Docs),
-            From ! {self(), committed},
-            exit(normal)
-    end.
-
-collector_commit(DbName, UserCtx, BatchInterval, Docs) ->
-    % unregister
-    unregister_collector(DbName, UserCtx, self()),
-    % wait and collect
-    Docs2 = shutdown_collector(DbName, UserCtx, BatchInterval, Docs),
-    {ok, _Revs} = commit_user_docs(DbName, UserCtx, Docs2).
-
-unregister_collector(DbName, UserCtx, Pid) ->
-    % remove from ets
-    ets:delete_object(couch_batch_save_by_db, {{DbName, UserCtx}, Pid}).
-
-shutdown_collector(DbName, UserCtx, BatchInterval, Docs) ->
-    receive
-        {From, add_doc, Doc} ->
-            From ! {self(), doc_added},
-            shutdown_collector(DbName, UserCtx, BatchInterval, [Doc|Docs])
-    % this interval will be waited for each time ensure-full-commit is called
-    after BatchInterval ->
-        Docs
-    end.
diff --git a/src/couchdb/couch_batch_save_sup.erl b/src/couchdb/couch_batch_save_sup.erl
deleted file mode 100644
index c18e2c1c..00000000
--- a/src/couchdb/couch_batch_save_sup.erl
+++ /dev/null
@@ -1,37 +0,0 @@
-% Licensed under the Apache License, Version 2.0 (the "License"); you may not
-% use this file except in compliance with the License. You may obtain a copy of
-% the License at
-%
-%   http://www.apache.org/licenses/LICENSE-2.0
-%
-% Unless required by applicable law or agreed to in writing, software
-% distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
-% WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
-% License for the specific language governing permissions and limitations under
-% the License.
-
--module(couch_batch_save_sup).
-
--behaviour(supervisor).
-
--export([start_link/0,init/1]).
-
-start_link() ->
-    supervisor:start_link({local, couch_batch_save_sup},
-        couch_batch_save_sup, []).
-
-init([]) ->
-    Self = self(),
-    ok = couch_config:register(
-        fun("couchdb", _) ->
-            exit(Self, reload_config)
-        end),
-
-    BatchSize = list_to_integer(couch_config:get("couchdb",
-        "batch_save_size","1000")),
-    BatchInterval = list_to_integer(couch_config:get("couchdb",
-        "batch_save_interval","1000")),
-
-    Batch = {batch, {couch_batch_save, start_link, [BatchSize, BatchInterval]},
-            permanent, 1000, worker, [couch_batch_save]},
-    {ok, {{one_for_one, 10, 3600}, [Batch]}}.
diff --git a/src/couchdb/couch_db.erl b/src/couchdb/couch_db.erl
index 736b80aa..2dbb88a3 100644
--- a/src/couchdb/couch_db.erl
+++ b/src/couchdb/couch_db.erl
@@ -586,25 +586,46 @@ set_commit_option(Options) ->
         [full_commit|Options]
     end.
 
+collect_results(UpdatePid, MRef, ResultsAcc) ->
+    receive
+    {result, UpdatePid, Result} ->
+        collect_results(UpdatePid, MRef, [Result | ResultsAcc]);
+    {done, UpdatePid} ->
+        {ok, ResultsAcc};
+    {retry, UpdatePid} ->
+        retry;
+    {'DOWN', MRef, _, _, Reason} ->
+        exit(Reason)
+    end.
+
 write_and_commit(#db{update_pid=UpdatePid, user_ctx=Ctx}=Db, DocBuckets,
         NonRepDocs, Options0) ->
     Options = set_commit_option(Options0),
-    case gen_server:call(UpdatePid, 
-            {update_docs, DocBuckets, NonRepDocs, Options}, infinity) of
-    {ok, Results} -> {ok, Results};
-    retry ->
-        % This can happen if the db file we wrote to was swapped out by
-        % compaction. Retry by reopening the db and writing to the current file
-        {ok, Db2} = open_ref_counted(Db#db.main_pid, Ctx),
-        DocBuckets2 = [[doc_flush_atts(Doc, Db2#db.fd) || Doc <- Bucket] || Bucket <- DocBuckets],
-        % We only retry once
-        close(Db2),
-        case gen_server:call(UpdatePid, {update_docs, DocBuckets2, NonRepDocs, Options}, infinity) of
+    MergeConflicts = lists:member(merge_conflicts, Options),
+    FullCommit = lists:member(full_commit, Options),
+    MRef = erlang:monitor(process, UpdatePid),
+    try
+        UpdatePid ! {update_docs, self(), DocBuckets, NonRepDocs, MergeConflicts, FullCommit},
+        case collect_results(UpdatePid, MRef, []) of
         {ok, Results} -> {ok, Results};
-        retry -> throw({update_error, compaction_retry})
+        retry ->
+            % This can happen if the db file we wrote to was swapped out by
+            % compaction. Retry by reopening the db and writing to the current file
+            {ok, Db2} = open_ref_counted(Db#db.main_pid, Ctx),
+            DocBuckets2 = [[doc_flush_atts(Doc, Db2#db.fd) || Doc <- Bucket] || Bucket <- DocBuckets],
+            % We only retry once
+            close(Db2),
+            UpdatePid ! {update_docs, self(), DocBuckets2, NonRepDocs, MergeConflicts, FullCommit},
+            case collect_results(UpdatePid, MRef, []) of
+            {ok, Results} -> {ok, Results};
+            retry -> throw({update_error, compaction_retry})
+            end
         end
+    after
+        erlang:demonitor(MRef, [flush])
     end.
 
+
 set_new_att_revpos(#doc{revs={RevPos,_Revs},atts=Atts}=Doc) ->
     Doc#doc{atts= lists:map(fun(#att{data={_Fd,_Sp}}=Att) ->
             % already commited to disk, do not set new rev
diff --git a/src/couchdb/couch_db_updater.erl b/src/couchdb/couch_db_updater.erl
index a13f9955..96a59944 100644
--- a/src/couchdb/couch_db_updater.erl
+++ b/src/couchdb/couch_db_updater.erl
@@ -43,19 +43,6 @@ terminate(Reason, _Srv) ->
 
 handle_call(get_db, _From, Db) ->
     {reply, {ok, Db}, Db};
-handle_call({update_docs, GroupedDocs, NonRepDocs, Options}, _From, Db) ->
-    try update_docs_int(Db, GroupedDocs, NonRepDocs, Options) of
-    {ok, Failures, Db2} ->
-        ok = gen_server:call(Db#db.main_pid, {db_updated, Db2}),
-        if Db2#db.update_seq /= Db#db.update_seq ->
-            couch_db_update_notifier:notify({updated, Db2#db.name});
-        true -> ok
-        end,
-        {reply, {ok, Failures}, Db2}
-    catch
-        throw: retry ->
-            {reply, retry, Db}
-    end;
 handle_call(full_commit, _From, #db{waiting_delayed_commit=nil}=Db) ->
     {reply, ok, Db}; % no data waiting, return ok immediately
 handle_call(full_commit, _From,  Db) ->
@@ -192,6 +179,63 @@ handle_cast({compact_done, CompactFilepath}, #db{filepath=Filepath}=Db) ->
         {noreply, Db2}
     end.
 
+
+merge_updates([], RestB, AccOutGroups) ->
+    lists:reverse(AccOutGroups, RestB);
+merge_updates(RestA, [], AccOutGroups) ->
+    lists:reverse(AccOutGroups, RestA);
+merge_updates([[{_, #doc{id=IdA}}|_]=GroupA | RestA],
+        [[{_, #doc{id=IdB}}|_]=GroupB | RestB], AccOutGroups) ->
+    if IdA == IdB ->
+        merge_updates(RestA, RestB, [GroupA ++ GroupB | AccOutGroups]);
+    IdA < IdB ->
+        merge_updates(RestA, [GroupB | RestB], [GroupA | AccOutGroups]);
+    true ->
+        merge_updates([GroupA | RestA], RestB, [GroupB | AccOutGroups])
+    end.
+
+collect_updates(GroupedDocsAcc, ClientsAcc, MergeConflicts, FullCommit) ->
+    receive
+        % only collect updates with the same MergeConflicts flag and without
+        % local docs. Makes it easier to avoid multiple local doc updaters.
+        {update_docs, Client, GroupedDocs, [], MergeConflicts, FullCommit2} ->
+            GroupedDocs2 = [[{Client, Doc} || Doc <- DocGroup]
+                    || DocGroup <- GroupedDocs],
+            GroupedDocsAcc2 = 
+                merge_updates(GroupedDocsAcc, GroupedDocs2, []),
+            collect_updates(GroupedDocsAcc2, [Client | ClientsAcc],
+                    MergeConflicts, (FullCommit or FullCommit2))
+    after 0 ->
+        {GroupedDocsAcc, ClientsAcc, FullCommit}
+    end.
+
+handle_info({update_docs, Client, GroupedDocs, NonRepDocs, MergeConflicts, 
+        FullCommit}, Db) ->
+    GroupedDocs2 = [[{Client, D} || D <- DocGroup] || DocGroup <- GroupedDocs],
+    if NonRepDocs == [] ->
+        {GroupedDocs3, Clients, FullCommit2} = collect_updates(GroupedDocs2, 
+                [Client], MergeConflicts, FullCommit);
+    true ->
+        GroupedDocs3 = GroupedDocs2,
+        FullCommit2 = FullCommit,
+        Clients = [Client]
+    end,
+    NonRepDocs2 = [{Client, NRDoc} || NRDoc <- NonRepDocs],
+    try update_docs_int(Db, GroupedDocs3, NonRepDocs2, MergeConflicts, 
+                FullCommit2) of
+    {ok, Db2} ->
+        ok = gen_server:call(Db#db.main_pid, {db_updated, Db2}),
+        if Db2#db.update_seq /= Db#db.update_seq ->
+            couch_db_update_notifier:notify({updated, Db2#db.name});
+        true -> ok
+        end,
+        [catch(ClientPid ! {done, self()}) || ClientPid <- Clients],
+        {noreply, Db2}
+    catch
+        throw: retry ->
+            [catch(ClientPid ! {retry, self()}) || ClientPid <- Clients],
+            {noreply, Db}
+    end;
 handle_info(delayed_commit, Db) ->
     {noreply, commit_data(Db)}.
 
@@ -399,18 +443,24 @@ flush_trees(#db{fd=Fd,header=Header}=Db,
         end, Unflushed),
     flush_trees(Db, RestUnflushed, [InfoUnflushed#full_doc_info{rev_tree=Flushed} | AccFlushed]).
 
-merge_rev_trees(_MergeConflicts, [], [], AccNewInfos, AccRemoveSeqs, AccConflicts, AccSeq) ->
-    {ok, lists:reverse(AccNewInfos), AccRemoveSeqs, AccConflicts, AccSeq};
+
+send_result(Client, Id, OriginalRevs, NewResult) ->
+    % used to send a result to the client
+    catch(Client ! {result, self(), {{Id, OriginalRevs}, NewResult}}).
+
+merge_rev_trees(_MergeConflicts, [], [], AccNewInfos, AccRemoveSeqs, AccSeq) ->
+    {ok, lists:reverse(AccNewInfos), AccRemoveSeqs, AccSeq};
 merge_rev_trees(MergeConflicts, [NewDocs|RestDocsList],
-        [OldDocInfo|RestOldInfo], AccNewInfos, AccRemoveSeqs, AccConflicts, AccSeq) ->
+        [OldDocInfo|RestOldInfo], AccNewInfos, AccRemoveSeqs, AccSeq) ->
     #full_doc_info{id=Id,rev_tree=OldTree,deleted=OldDeleted,update_seq=OldSeq}
             = OldDocInfo,
-    {NewRevTree, NewConflicts} = lists:foldl(
-        fun(#doc{revs={Pos,[_Rev|PrevRevs]}}=NewDoc, {AccTree, AccConflicts2}) ->
+    NewRevTree = lists:foldl(
+        fun({Client, #doc{revs={Pos,[_Rev|PrevRevs]}}=NewDoc}, AccTree) ->
             if not MergeConflicts ->
                 case couch_key_tree:merge(AccTree, [couch_db:doc_to_tree(NewDoc)]) of
                 {_NewTree, conflicts} when (not OldDeleted) ->
-                    {AccTree, [{{Id, {Pos-1,PrevRevs}}, conflict} | AccConflicts2]};
+                    send_result(Client, Id, {Pos-1,PrevRevs}, conflict),
+                    AccTree;
                 {NewTree, no_conflicts} when  AccTree == NewTree ->
                     % the tree didn't change at all
                     % meaning we are saving a rev that's already
@@ -426,26 +476,28 @@ merge_rev_trees(MergeConflicts, [NewDocs|RestDocsList],
                         NewDoc2 = NewDoc#doc{revs={OldPos + 1, [NewRevId, OldRev]}},
                         {NewTree2, _} = couch_key_tree:merge(AccTree,
                                 [couch_db:doc_to_tree(NewDoc2)]),
-                        % we changed the rev id, this tells the caller we did.
-                        {NewTree2, [{{Id, {Pos-1,PrevRevs}}, {ok, {OldPos + 1, NewRevId}}}
-                                | AccConflicts2]};
+                        % we changed the rev id, this tells the caller we did
+                        send_result(Client, Id, {Pos-1,PrevRevs}, 
+                                {ok, {OldPos + 1, NewRevId}}),
+                        NewTree2;
                     true ->
-                        {AccTree, [{{Id, {Pos-1,PrevRevs}}, conflict} | AccConflicts2]}
+                        send_result(Client, Id, {Pos-1,PrevRevs}, conflict),
+                        AccTree
                     end;
                 {NewTree, _} ->
-                    {NewTree, AccConflicts2}
+                    NewTree
                 end;
             true ->
                 {NewTree, _} = couch_key_tree:merge(AccTree,
                             [couch_db:doc_to_tree(NewDoc)]),
-                {NewTree, AccConflicts2}
+                NewTree
             end 
         end,
-        {OldTree, AccConflicts}, NewDocs),
+        OldTree, NewDocs),
     if NewRevTree == OldTree ->
         % nothing changed
         merge_rev_trees(MergeConflicts, RestDocsList, RestOldInfo, AccNewInfos,
-                AccRemoveSeqs, NewConflicts, AccSeq);
+                AccRemoveSeqs, AccSeq);
     true ->
         % we have updated the document, give it a new seq #
         NewInfo = #full_doc_info{id=Id,update_seq=AccSeq+1,rev_tree=NewRevTree},
@@ -454,7 +506,7 @@ merge_rev_trees(MergeConflicts, [NewDocs|RestDocsList],
             _ -> [OldSeq | AccRemoveSeqs]
         end,
         merge_rev_trees(MergeConflicts, RestDocsList, RestOldInfo,
-                [NewInfo|AccNewInfos], RemoveSeqs, NewConflicts, AccSeq+1)
+                [NewInfo|AccNewInfos], RemoveSeqs, AccSeq+1)
     end.
 
 
@@ -473,13 +525,13 @@ stem_full_doc_infos(#db{revs_limit=Limit}, DocInfos) ->
     [Info#full_doc_info{rev_tree=couch_key_tree:stem(Tree, Limit)} ||
             #full_doc_info{rev_tree=Tree}=Info <- DocInfos].
 
-update_docs_int(Db, DocsList, NonRepDocs, Options) ->
+update_docs_int(Db, DocsList, NonRepDocs, MergeConflicts, FullCommit) ->
     #db{
         fulldocinfo_by_id_btree = DocInfoByIdBTree,
         docinfo_by_seq_btree = DocInfoBySeqBTree,
         update_seq = LastSeq
         } = Db,
-    Ids = [Id || [#doc{id=Id}|_] <- DocsList],
+    Ids = [Id || [{_Client, #doc{id=Id}}|_] <- DocsList],
     % lookup up the old documents, if they exist.
     OldDocLookups = couch_btree:lookup(DocInfoByIdBTree, Ids),
     OldDocInfos = lists:zipwith(
@@ -489,17 +541,15 @@ update_docs_int(Db, DocsList, NonRepDocs, Options) ->
             #full_doc_info{id=Id}
         end,
         Ids, OldDocLookups),
-
     % Merge the new docs into the revision trees.
-    {ok, NewDocInfos0, RemoveSeqs, Conflicts, NewSeq} = merge_rev_trees(
-            lists:member(merge_conflicts, Options),
-            DocsList, OldDocInfos, [], [], [], LastSeq),
+    {ok, NewDocInfos0, RemoveSeqs, NewSeq} = merge_rev_trees(
+            MergeConflicts, DocsList, OldDocInfos, [], [], LastSeq),
 
     NewFullDocInfos = stem_full_doc_infos(Db, NewDocInfos0),
 
     % All documents are now ready to write.
 
-    {ok, LocalConflicts, Db2}  = update_local_docs(Db, NonRepDocs),
+    {ok, Db2}  = update_local_docs(Db, NonRepDocs),
 
     % Write out the document summaries (the bodies are stored in the nodes of
     % the trees, the attachments are already written to disk)
@@ -526,15 +576,14 @@ update_docs_int(Db, DocsList, NonRepDocs, Options) ->
         Db4 = refresh_validate_doc_funs(Db3)
     end,
 
-    {ok, LocalConflicts ++ Conflicts,
-            commit_data(Db4, not lists:member(full_commit, Options))}.
+    {ok, commit_data(Db4, not FullCommit)}.
 
 
 update_local_docs(#db{local_docs_btree=Btree}=Db, Docs) ->
-    Ids = [Id || #doc{id=Id} <- Docs],
+    Ids = [Id || {_Client, #doc{id=Id}} <- Docs],
     OldDocLookups = couch_btree:lookup(Btree, Ids),
     BtreeEntries = lists:zipwith(
-        fun(#doc{id=Id,deleted=Delete,revs={0,PrevRevs},body=Body}, OldDocLookup) ->
+        fun({Client, #doc{id=Id,deleted=Delete,revs={0,PrevRevs},body=Body}}, OldDocLookup) ->
             case PrevRevs of
             [RevStr|_] ->
                 PrevRev = list_to_integer(?b2l(RevStr));
@@ -549,28 +598,28 @@ update_local_docs(#db{local_docs_btree=Btree}=Db, Docs) ->
             case OldRev == PrevRev of
             true ->
                 case Delete of
-                    false -> {update, {Id, {PrevRev + 1, PrevRevs, Body}}};
-                    true  -> {remove, Id, PrevRevs}
+                    false ->
+                        send_result(Client, Id, {0, PrevRevs}, {ok,
+                                {0, ?l2b(integer_to_list(PrevRev + 1))}}),
+                        {update, {Id, {PrevRev + 1, Body}}};
+                    true  ->
+                        send_result(Client, Id, {0, PrevRevs},
+                                {ok, {0, <<"0">>}}),
+                        {remove, Id}
                 end;
             false ->
-                {conflict, {Id, {0, PrevRevs}}}
+                send_result(Client, Id, {0, PrevRevs}, conflict),
+                ignore
             end
         end, Docs, OldDocLookups),
 
-    BtreeIdsRemove = [Id || {remove, Id, _PrevRevs} <- BtreeEntries],
-    BtreeIdsUpdate = [{Id, {NewRev, Body}} || {update, {Id, {NewRev, _OldRevs, Body}}} <- BtreeEntries],
-    Results = 
-            [{{Id, {0, PrevRevs}}, {ok, {0, <<"0">>}}}
-                || {remove, Id, PrevRevs} <- BtreeEntries] ++
-            [{{Id, {0, PrevRevs}}, {ok, {0, ?l2b(integer_to_list(NewRev))}}}
-                || {update, {Id, {NewRev, PrevRevs, _Body}}} <- BtreeEntries] ++
-            [{IdRevs, conflict}
-                || {conflict, IdRevs} <- BtreeEntries],
+    BtreeIdsRemove = [Id || {remove, Id} <- BtreeEntries],
+    BtreeIdsUpdate = [{Key, Val} || {update, {Key, Val}} <- BtreeEntries],
 
     {ok, Btree2} =
         couch_btree:add_remove(Btree, BtreeIdsUpdate, BtreeIdsRemove),
 
-    {ok, Results, Db#db{local_docs_btree = Btree2}}.
+    {ok, Db#db{local_docs_btree = Btree2}}.
 
 
 commit_data(Db) ->
diff --git a/src/couchdb/couch_httpd_db.erl b/src/couchdb/couch_httpd_db.erl
index 3945498d..f7fd24a8 100644
--- a/src/couchdb/couch_httpd_db.erl
+++ b/src/couchdb/couch_httpd_db.erl
@@ -349,9 +349,15 @@ db_req(#httpd{method='POST',path_parts=[DbName]}=Req, Db) ->
     DocId = Doc2#doc.id,
     case couch_httpd:qs_value(Req, "batch") of
     "ok" ->
-        % batch
-        ok = couch_batch_save:eventually_save_doc(
-            Db#db.name, Doc2, Db#db.user_ctx),
+        % async_batching
+        spawn(fun() ->
+                case catch(couch_db:update_doc(Db, Doc2, [])) of
+                {ok, _} -> ok;
+                Error ->
+                    ?LOG_INFO("Batch doc error (~s): ~p",[DocId, Error])
+                end
+            end),
+            
         send_json(Req, 202, [], {[
             {ok, true},
             {id, DocId}
@@ -378,7 +384,6 @@ db_req(#httpd{method='POST',path_parts=[_,<<"_ensure_full_commit">>]}=Req, Db) -
     {ok, StartTime} =
     case couch_httpd:qs_value(Req, "seq") of
     undefined ->
-        committed = couch_batch_save:commit_now(Db#db.name, Db#db.user_ctx),
         couch_db:ensure_full_commit(Db);
     RequiredStr ->
         RequiredSeq = list_to_integer(RequiredStr),
@@ -749,7 +754,14 @@ db_doc_req(#httpd{method='PUT'}=Req, Db, DocId) ->
     "ok" ->
         % batch
         Doc = couch_doc_from_req(Req, DocId, Json),
-        ok = couch_batch_save:eventually_save_doc(Db#db.name, Doc, Db#db.user_ctx),
+        
+        spawn(fun() ->
+                case catch(couch_db:update_doc(Db, Doc, [])) of
+                {ok, _} -> ok;
+                Error ->
+                    ?LOG_INFO("Batch doc error (~s): ~p",[DocId, Error])
+                end
+            end),
         send_json(Req, 202, [], {[
             {ok, true},
             {id, DocId}