--- Revision None
+++ Revision 313037313236
@@ -0,0 +1,79 @@
+diff --git a/etc/couchdb/default.ini.tpl.in b/etc/couchdb/default.ini.tpl.in
+index 8207d6e..e05ddd2 100644
+--- a/etc/couchdb/default.ini.tpl.in
++++ b/etc/couchdb/default.ini.tpl.in
+@@ -12,6 +12,10 @@ max_dbs_open = 100
+ delayed_commits = true ; set this to false to ensure an fsync before 201 Created is returned
+ uri_file = %localstaterundir%/couch.uri
+ 
++[database_compaction]
++doc_buffer_size = 1048576 ; value in bytes
++checkpoint_after = 10485760 ; checkpoint after every N bytes were written
++
+ [httpd]
+ port = 5984
+ bind_address = 127.0.0.1
+diff --git a/src/couchdb/couch_db_updater.erl b/src/couchdb/couch_db_updater.erl
+index fef4032..4a626b0 100644
+--- a/src/couchdb/couch_db_updater.erl
++++ b/src/couchdb/couch_db_updater.erl
+@@ -858,32 +858,48 @@ copy_compact(Db, NewDb0, Retry) ->
+     FsyncOptions = [Op || Op <- NewDb0#db.fsync_options, Op == before_header],
+     NewDb = NewDb0#db{fsync_options=FsyncOptions},
+     TotalChanges = couch_db:count_changes_since(Db, NewDb#db.update_seq),
++    BufferSize = list_to_integer(
++        couch_config:get("database_compaction", "doc_buffer_size", "1048576")),
++    CheckpointAfter = list_to_integer(
++        couch_config:get("database_compaction", "checkpoint_after", "10485760")),
++
+     EnumBySeqFun =
+-    fun(#doc_info{high_seq=Seq}=DocInfo, _Offset, {AccNewDb, AccUncopied, TotalCopied}) ->
+-        couch_task_status:update("Copied ~p of ~p changes (~p%)",
+-                [TotalCopied, TotalChanges, (TotalCopied*100) div TotalChanges]),
+-        if TotalCopied rem 1000 =:= 0 ->
+-            NewDb2 = copy_docs(Db, AccNewDb, lists:reverse([DocInfo | AccUncopied]), Retry),
+-            if TotalCopied rem 10000 =:= 0 ->
+-                {ok, {commit_data(NewDb2#db{update_seq=Seq}), [], TotalCopied + 1}};
++    fun(#doc_info{high_seq=Seq}=DocInfo, _Offset,
++        {AccNewDb, AccUncopied, AccUncopiedSize, AccCopiedSize, TotalCopied}) ->
++
++        AccUncopiedSize2 = AccUncopiedSize + byte_size(term_to_binary(DocInfo)),
++        if AccUncopiedSize2 >= BufferSize ->
++            NewDb2 = copy_docs(
++                Db, AccNewDb, lists:reverse([DocInfo | AccUncopied]), Retry),
++            TotalCopied2 = TotalCopied + 1 + length(AccUncopied),
++            couch_task_status:update("Copied ~p of ~p changes (~p%)",
++                [TotalCopied2, TotalChanges, (TotalCopied2 * 100) div TotalChanges]),
++            AccCopiedSize2 = AccCopiedSize + AccUncopiedSize2,
++            if AccCopiedSize2 >= CheckpointAfter ->
++                {ok, {commit_data(NewDb2#db{update_seq = Seq}), [],
++                    0, 0, TotalCopied2}};
+             true ->
+-                {ok, {NewDb2#db{update_seq=Seq}, [], TotalCopied + 1}}
++                {ok, {NewDb2#db{update_seq = Seq}, [],
++                    0, AccCopiedSize2, TotalCopied2}}
+             end;
+         true ->
+-            {ok, {AccNewDb, [DocInfo | AccUncopied], TotalCopied + 1}}
++            {ok, {AccNewDb, [DocInfo | AccUncopied], AccUncopiedSize2,
++                AccCopiedSize, TotalCopied}}
+         end
+     end,
+ 
+     couch_task_status:set_update_frequency(500),
++    couch_task_status:update("Copied 0 of ~p changes (0%)", [TotalChanges]),
+ 
+-    {ok, _, {NewDb2, Uncopied, TotalChanges}} =
++    {ok, _, {NewDb2, Uncopied, _, _, ChangesDone}} =
+         couch_btree:foldl(Db#db.docinfo_by_seq_btree, EnumBySeqFun,
+-            {NewDb, [], 0},
++            {NewDb, [], 0, 0, 0},
+             [{start_key, NewDb#db.update_seq + 1}]),
+ 
+     couch_task_status:update("Flushing"),
+ 
+     NewDb3 = copy_docs(Db, NewDb2, lists:reverse(Uncopied), Retry),
++    TotalChanges = ChangesDone + length(Uncopied),
+ 
+     % copy misc header values
+     if NewDb3#db.security /= Db#db.security ->