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authorDamien F. Katz <damien@apache.org>2008-05-29 20:51:14 +0000
committerDamien F. Katz <damien@apache.org>2008-05-29 20:51:14 +0000
commit7e897a21ca5fa417b63abce023e775d55d3b6641 (patch)
treef5bbcad9f631755b21d3fbe68409021da351f4f0 /src
parent333d18cf62273159fe6c86e0f11d35511e6f8fb3 (diff)
Grouped reduce support. Needs performance work.
git-svn-id: https://svn.apache.org/repos/asf/incubator/couchdb/trunk@661476 13f79535-47bb-0310-9956-ffa450edef68
Diffstat (limited to 'src')
-rw-r--r--src/couchdb/couch_btree.erl237
-rw-r--r--src/couchdb/couch_httpd.erl68
-rw-r--r--src/couchdb/couch_view.erl32
3 files changed, 228 insertions, 109 deletions
diff --git a/src/couchdb/couch_btree.erl b/src/couchdb/couch_btree.erl
index 3d95ae5c..f5111c28 100644
--- a/src/couchdb/couch_btree.erl
+++ b/src/couchdb/couch_btree.erl
@@ -13,8 +13,8 @@
-module(couch_btree).
-export([open/2, open/3, query_modify/4, add/2, add_remove/3, foldl/3, foldl/4]).
--export([foldr/3, foldr/4, fold/4, fold/5, reduce/3, partial_reduce/3, final_reduce/2]).
--export([lookup/2, get_state/1, set_options/2, test/1, test/0]).
+-export([foldr/3, foldr/4, fold/4, fold/5, full_reduce/1, final_reduce/2]).
+-export([fold_reduce/7, lookup/2, get_state/1, set_options/2, test/1, test/0]).
-define(CHUNK_THRESHOLD, 16#fff).
@@ -68,25 +68,33 @@ final_reduce(Reduce, {[], Reductions}) ->
final_reduce(Reduce, {KVs, Reductions}) ->
Red = Reduce(reduce, KVs),
final_reduce(Reduce, {[], [Red | Reductions]}).
-
-reduce(Bt, Key1, Key2) ->
- {ok, Reds} = partial_reduce(Bt, Key1, Key2),
- {ok, final_reduce(Bt, Reds)}.
-partial_reduce(#btree{root=Root}=Bt, Key1, Key2) ->
- {KeyStart, KeyEnd} =
- case Key1 == nil orelse Key2 == nil orelse less(Bt, Key1, Key2) of
- true -> {Key1, Key2};
- false -> {Key2, Key1}
+fold_reduce(Bt, StartKey, EndKey, KeyGroupFun, Fun, Acc) ->
+ fold_reduce(Bt, fwd, StartKey, EndKey, KeyGroupFun, Fun, Acc).
+
+fold_reduce(#btree{root=Root}=Bt, Dir, StartKey, EndKey, KeyGroupFun, Fun, Acc) ->
+ {StartKey2, EndKey2} =
+ case Dir of
+ rev -> {EndKey, StartKey};
+ fwd -> {StartKey, EndKey}
end,
- case Root of
- nil ->
- {ok, {[], []}};
- _ ->
- {KVs, Nodes} = collect_node(Bt, Root, KeyStart, KeyEnd),
- {ok, {KVs, [Red || {_K,{_P,Red}} <- Nodes]}}
+ {ok, Acc2, GroupedRedsAcc2, GroupedKVsAcc2, GroupedKey2} =
+ reduce_stream_node(Bt, Dir, Root, StartKey2, EndKey2, nil, [], [],
+ KeyGroupFun, Fun, Acc),
+ if GroupedKey2 == nil ->
+ {ok, Acc2};
+ true ->
+ case (catch Fun(GroupedKey2, {GroupedKVsAcc2, GroupedRedsAcc2}, Acc2)) of
+ {ok, Acc3} -> {ok, Acc3};
+ {stop, Acc3} -> {ok, Acc3};
+ Else -> throw(Else)
+ end
end.
-
+
+full_reduce(#btree{root=nil,reduce=Reduce}) ->
+ {ok, Reduce(reduce, [])};
+full_reduce(#btree{root={_P, Red}}) ->
+ {ok, Red}.
foldl(Bt, Fun, Acc) ->
fold(Bt, fwd, Fun, Acc).
@@ -390,17 +398,21 @@ modify_kvnode(Bt, [{Key, Value} | RestKVs], [{ActionType, ActionKey, ActionValue
end.
-collect_node(_Bt, {P, R}, nil, nil) ->
- {[], [{nil, {P,R}}]};
-collect_node(Bt, {P, R}, KeyStart, KeyEnd) ->
+reduce_stream_node(Bt, Dir, {P, _R}, KeyStart, KeyEnd, GroupedKey, GroupedKVsAcc,
+ GroupedRedsAcc, KeyGroupFun, Fun, Acc) ->
case get_node(Bt, P) of
{kp_node, NodeList} ->
- collect_kp_node(Bt, NodeList, KeyStart, KeyEnd);
+ reduce_stream_kp_node(Bt, Dir, NodeList, KeyStart, KeyEnd, GroupedKey,
+ GroupedKVsAcc, GroupedRedsAcc, KeyGroupFun, Fun, Acc);
{kv_node, KVs} ->
- collect_kv_node(Bt, {P,R}, KVs, KeyStart, KeyEnd)
+ reduce_stream_kv_node(Bt, Dir, KVs, KeyStart, KeyEnd, GroupedKey,
+ GroupedKVsAcc, GroupedRedsAcc, KeyGroupFun, Fun, Acc)
end.
-collect_kv_node(Bt, {P,R}, KVs, KeyStart, KeyEnd) ->
+reduce_stream_kv_node(Bt, Dir, KVs, KeyStart, KeyEnd,
+ GroupedKey, GroupedKVsAcc, GroupedRedsAcc,
+ KeyGroupFun, Fun, Acc) ->
+
GTEKeyStartKVs =
case KeyStart of
nil ->
@@ -413,20 +425,45 @@ collect_kv_node(Bt, {P,R}, KVs, KeyStart, KeyEnd) ->
nil ->
GTEKeyStartKVs;
_ ->
- lists:dropwhile(
- fun({Key,_}) ->
- less(Bt, KeyEnd, Key)
- end, lists:reverse(GTEKeyStartKVs))
+ lists:takewhile(
+ fun({Key,_}) ->
+ not less(Bt, KeyEnd, Key)
+ end, GTEKeyStartKVs)
end,
- case length(KVs2) == length(KVs) of
- true -> % got full node, return the already calculated reduction
- {[], [{nil, {P, R}}]};
- false -> % otherwise return the keyvalues for later reduction
- {[assemble(Bt,K,V) || {K,V} <- KVs2], []}
+ reduce_stream_kv_node2(Bt, adjust_dir(Dir, KVs2), GroupedKey, GroupedKVsAcc, GroupedRedsAcc,
+ KeyGroupFun, Fun, Acc).
+
+
+reduce_stream_kv_node2(_Bt, [], GroupedKey, GroupedKVsAcc, GroupedRedsAcc,
+ _KeyGroupFun, _Fun, Acc) ->
+ {ok, Acc, GroupedRedsAcc, GroupedKVsAcc, GroupedKey};
+reduce_stream_kv_node2(Bt, [{Key, Value}| RestKVs], GroupedKey, GroupedKVsAcc,
+ GroupedRedsAcc, KeyGroupFun, Fun, Acc) ->
+ case GroupedKey of
+ nil ->
+ reduce_stream_kv_node2(Bt, RestKVs, Key,
+ [assemble(Bt,Key,Value)], [], KeyGroupFun, Fun, Acc);
+ _ ->
+
+ case KeyGroupFun(GroupedKey, Key) of
+ true ->
+ reduce_stream_kv_node2(Bt, RestKVs, GroupedKey,
+ [assemble(Bt,Key,Value)|GroupedKVsAcc], GroupedRedsAcc, KeyGroupFun,
+ Fun, Acc);
+ false ->
+ case Fun(GroupedKey, {GroupedKVsAcc, GroupedRedsAcc}, Acc) of
+ {ok, Acc2} ->
+ reduce_stream_kv_node2(Bt, RestKVs, Key, [assemble(Bt,Key,Value)],
+ [], KeyGroupFun, Fun, Acc2);
+ {stop, Acc2} ->
+ throw({stop, Acc2})
+ end
+ end
end.
-
-
-collect_kp_node(Bt, NodeList, KeyStart, KeyEnd) ->
+
+reduce_stream_kp_node(Bt, Dir, NodeList, KeyStart, KeyEnd,
+ GroupedKey, GroupedKVsAcc, GroupedRedsAcc,
+ KeyGroupFun, Fun, Acc) ->
Nodes =
case KeyStart of
nil ->
@@ -437,48 +474,52 @@ collect_kp_node(Bt, NodeList, KeyStart, KeyEnd) ->
less(Bt, Key, KeyStart)
end, NodeList)
end,
-
+ NodesInRange =
case KeyEnd of
nil ->
- case Nodes of
- [] ->
- {[], []};
- [{_, StartNodeInfo}|RestNodes] ->
- {DownKVs, DownNodes} = collect_node(Bt, StartNodeInfo, KeyStart, KeyEnd),
- {DownKVs, DownNodes ++ RestNodes}
- end;
+ Nodes;
_ ->
- {GTEKeyEndNodes, LTKeyEndNodes} = lists:splitwith(
+ {InRange, MaybeInRange} = lists:splitwith(
fun({Key,_}) ->
- not less(Bt, Key, KeyEnd)
- end, lists:reverse(Nodes)),
-
- {MatchingKVs, MatchingNodes} =
- case lists:reverse(LTKeyEndNodes) of
- [{_, StartNodeInfo}] ->
- collect_node(Bt, StartNodeInfo, KeyStart, KeyEnd);
- [{_, StartNodeInfo}|RestLTNodes] ->
- % optimization, since we have more KP nodes in range, we don't need
- % to provide the endkey when searching the start node, making
- % collecting the node faster.
- {DownKVs, DownNodes} = collect_node(Bt, StartNodeInfo, KeyStart, nil),
- {DownKVs, DownNodes ++ RestLTNodes};
- [] ->
- {[], []}
- end,
-
- case lists:reverse(GTEKeyEndNodes) of
- [{_, EndNodeInfo} | _] when LTKeyEndNodes == [] ->
- collect_node(Bt, EndNodeInfo, KeyStart, KeyEnd);
- [{_, EndNodeInfo} | _] ->
- {KVs1, DownNodes1} = collect_node(Bt, EndNodeInfo, nil, KeyEnd),
- {KVs1 ++ MatchingKVs, DownNodes1 ++ MatchingNodes};
- [] ->
- {MatchingKVs, MatchingNodes}
- end
+ less(Bt, Key, KeyEnd)
+ end, Nodes),
+ InRange ++ case MaybeInRange of [] -> []; [FirstMaybe|_] -> [FirstMaybe] end
+ end,
+ reduce_stream_kp_node2(Bt, Dir, adjust_dir(Dir, NodesInRange), KeyStart, KeyEnd,
+ GroupedKey, GroupedKVsAcc, GroupedRedsAcc, KeyGroupFun, Fun, Acc).
+
+
+reduce_stream_kp_node2(Bt, Dir, [{_Key, NodeInfo} | RestNodeList], KeyStart, KeyEnd,
+ nil, [], [], KeyGroupFun, Fun, Acc) ->
+ {ok, Acc2, GroupedRedsAcc2, GroupedKVsAcc2, GroupedKey2} =
+ reduce_stream_node(Bt, Dir, NodeInfo, KeyStart, KeyEnd, nil,
+ [], [], KeyGroupFun, Fun, Acc),
+ reduce_stream_kp_node2(Bt, Dir, RestNodeList, KeyStart, KeyEnd, GroupedKey2,
+ GroupedKVsAcc2, GroupedRedsAcc2, KeyGroupFun, Fun, Acc2);
+reduce_stream_kp_node2(Bt, Dir, NodeList, KeyStart, KeyEnd,
+ GroupedKey, GroupedKVsAcc, GroupedRedsAcc, KeyGroupFun, Fun, Acc) ->
+ {Grouped0, Ungrouped0} = lists:splitwith(fun({Key,_}) ->
+ KeyGroupFun(GroupedKey, Key) end, NodeList),
+ {GroupedNodes, UngroupedNodes} =
+ case Grouped0 of
+ [] ->
+ {Grouped0, Ungrouped0};
+ _ ->
+ [FirstGrouped | RestGrouped] = lists:reverse(Grouped0),
+ {RestGrouped, [FirstGrouped | Ungrouped0]}
+ end,
+ GroupedReds = [R || {_, {_,R}} <- GroupedNodes],
+ case UngroupedNodes of
+ [{_Key, NodeInfo}|RestNodes] ->
+ {ok, Acc2, GroupedRedsAcc2, GroupedKVsAcc2, GroupedKey2} =
+ reduce_stream_node(Bt, Dir, NodeInfo, KeyStart, KeyEnd, GroupedKey,
+ GroupedKVsAcc, GroupedReds ++ GroupedRedsAcc, KeyGroupFun, Fun, Acc),
+ reduce_stream_kp_node2(Bt, Dir, RestNodes, KeyStart, KeyEnd, GroupedKey2,
+ GroupedKVsAcc2, GroupedRedsAcc2, KeyGroupFun, Fun, Acc2);
+ [] ->
+ {ok, Acc, GroupedReds ++ GroupedRedsAcc, GroupedKVsAcc, GroupedKey}
end.
-
adjust_dir(fwd, List) ->
List;
adjust_dir(rev, List) ->
@@ -624,22 +665,10 @@ test_btree(KeyValues) ->
Len = length(KeyValues),
-
- {ok, Len} = reduce(Btree10, nil, nil),
-
- % Count of all from start to Val1
- Val1 = Len div 3,
- {ok, Val1} = reduce(Btree10, nil, Val1),
- % Count of all from Val1 to end
- CountVal1ToEnd = Len - Val1 + 1,
- {ok, CountVal1ToEnd} = reduce(Btree10, Val1, nil),
-
- % Count of all from Val1 to Val2
- Val2 = 2*Len div 3,
- CountValRange = Val2 - Val1 + 1,
- {ok, CountValRange} = reduce(Btree10, Val1, Val2),
% get the leading reduction as we foldl/r
+ % and count of all from start to Val1
+ Val1 = Len div 3,
{ok, true} = foldl(Btree10, Val1, fun(_X, LeadingReds, _Acc) ->
CountToStart = Val1 - 1,
CountToStart = final_reduce(Btree10, LeadingReds),
@@ -706,8 +735,44 @@ test_btree(KeyValues) ->
% verify the remaining
ok = test_keys(Btree80, A),
+
+ {ok, Btree90} = test_remove(Btree80, A),
+
+ EvenOdd = fun(V) when V rem 2 == 1 -> "odd"; (_) -> "even" end,
+
+ EvenOddKVs = [{{EvenOdd(Key),Key}, 1} || {Key, _} <- KeyValues],
+ {ok, Btree100} = test_add(Btree90, EvenOddKVs),
+ GroupingFun = fun({K1, _},{K2,_}) -> K1 == K2 end,
+ FoldFun = fun(GroupedKey, Unreduced, Acc) ->
+ {ok, [{GroupedKey, final_reduce(Btree100, Unreduced)} | Acc]}
+ end,
+
+ Half = Len div 2,
+
+ {ok, [{{"odd", _}, Half}, {{"even",_}, Half}]} =
+ fold_reduce(Btree100, nil, nil, GroupingFun, FoldFun, []),
+
+ {ok, [{{"even",_}, Half}, {{"odd", _}, Half}]} =
+ fold_reduce(Btree100, rev, nil, nil, GroupingFun, FoldFun, []),
+
+ {ok, [{{"even",_}, Half}]} =
+ fold_reduce(Btree100, fwd, {"even", -1}, {"even", foo}, GroupingFun, FoldFun, []),
+
+ {ok, [{{"even",_}, Half}]} =
+ fold_reduce(Btree100, rev, {"even", foo}, {"even", -1}, GroupingFun, FoldFun, []),
+
+ {ok, [{{"odd",_}, Half}]} =
+ fold_reduce(Btree100, fwd, {"odd", -1}, {"odd", foo}, GroupingFun, FoldFun, []),
+
+ {ok, [{{"odd",_}, Half}]} =
+ fold_reduce(Btree100, rev, {"odd", foo}, {"odd", -1}, GroupingFun, FoldFun, []),
+
+ {ok, [{{"odd", _}, Half}, {{"even",_}, Half}]} =
+ fold_reduce(Btree100, {"even", -1}, {"odd", foo}, GroupingFun, FoldFun, []),
+
ok = couch_file:close(Fd).
+
diff --git a/src/couchdb/couch_httpd.erl b/src/couchdb/couch_httpd.erl
index d90402e1..bc99e4d5 100644
--- a/src/couchdb/couch_httpd.erl
+++ b/src/couchdb/couch_httpd.erl
@@ -34,7 +34,8 @@
direction = fwd,
start_docid = nil,
end_docid = <<>>,
- skip = 0
+ skip = 0,
+ group_level = 0
}).
start_link(BindAddress, Port, DocumentRoot) ->
@@ -349,12 +350,10 @@ handle_db_request(_Req, _Method, {_DbName, _Db, ["_all_docs_by_seq"]}) ->
handle_db_request(Req, 'GET', {DbName, _Db, ["_view", DocId, ViewName]}) ->
#view_query_args{
start_key = StartKey,
- end_key = EndKey,
count = Count,
skip = SkipCount,
direction = Dir,
- start_docid = StartDocId,
- end_docid = EndDocId
+ start_docid = StartDocId
} = QueryArgs = parse_view_query(Req),
case couch_view:get_map_view({DbName, "_design/" ++ DocId, ViewName}) of
{ok, View} ->
@@ -368,8 +367,7 @@ handle_db_request(Req, 'GET', {DbName, _Db, ["_view", DocId, ViewName]}) ->
{not_found, Reason} ->
case couch_view:get_reduce_view({DbName, "_design/" ++ DocId, ViewName}) of
{ok, View} ->
- {ok, Value} = couch_view:reduce(View, {StartKey, StartDocId}, {EndKey, EndDocId}),
- send_json(Req, {obj, [{ok,true}, {result, Value}]});
+ output_reduce_view(Req, View);
_ ->
throw({not_found, Reason})
end
@@ -398,12 +396,10 @@ handle_db_request(Req, 'POST', {_DbName, Db, ["_increment_update_seq"]}) ->
handle_db_request(Req, 'POST', {DbName, _Db, ["_temp_view"]}) ->
#view_query_args{
start_key = StartKey,
- end_key = EndKey,
count = Count,
skip = SkipCount,
direction = Dir,
- start_docid = StartDocId,
- end_docid = EndDocId
+ start_docid = StartDocId
} = QueryArgs = parse_view_query(Req),
case Req:get_primary_header_value("content-type") of
@@ -428,8 +424,7 @@ handle_db_request(Req, 'POST', {DbName, _Db, ["_temp_view"]}) ->
RedSrc ->
{ok, View} = couch_view:get_reduce_view(
{temp, DbName, Language, MapSrc, RedSrc}),
- {ok, Value} = couch_view:reduce(View, {StartKey, StartDocId}, {EndKey, EndDocId}),
- send_json(Req, {obj, [{ok,true}, {result, Value}]})
+ output_reduce_view(Req, View)
end;
handle_db_request(_Req, _Method, {_DbName, _Db, ["_temp_view"]}) ->
@@ -447,6 +442,53 @@ handle_db_request(Req, Method, {DbName, Db, [DocId, FileName]}) ->
handle_attachment_request(Req, Method, DbName, Db, UnquotedDocId,
UnquotedFileName).
+output_reduce_view(Req, View) ->
+ #view_query_args{
+ start_key = StartKey,
+ end_key = EndKey,
+ count = Count,
+ skip = Skip,
+ direction = Dir,
+ start_docid = StartDocId,
+ end_docid = EndDocId,
+ group_level = GroupLevel
+ } = parse_view_query(Req),
+ GroupRowsFun =
+ fun({_Key1,_}, {_Key2,_}) when GroupLevel == 0 ->
+ true;
+ ({Key1,_}, {Key2,_})
+ when is_integer(GroupLevel) and is_tuple(Key1) and is_tuple(Key2) ->
+ lists:sublist(tuple_to_list(Key1), GroupLevel) == lists:sublist(tuple_to_list(Key2), GroupLevel);
+ ({Key1,_}, {Key2,_}) ->
+ Key1 == Key2
+ end,
+ Resp = start_json_response(Req, 200),
+ Resp:write_chunk("{\"rows\":["),
+ {ok, _} = couch_view:fold_reduce(View, Dir, {StartKey, StartDocId}, {EndKey, EndDocId},
+ GroupRowsFun,
+ fun(_Key, _Red, {AccSeparator,AccSkip,AccCount}) when AccSkip > 0 ->
+ {ok, {AccSeparator,AccSkip-1,AccCount}};
+ (_Key, _Red, {AccSeparator,0,AccCount}) when AccCount == 0 ->
+ {stop,{AccSeparator,0,AccCount}};
+ (_Key, Red, {AccSeparator,0,AccCount}) when GroupLevel == 0 ->
+ Json = lists:flatten(cjson:encode({obj, [{key, null}, {value, Red}]})),
+ Resp:write_chunk(AccSeparator ++ Json),
+ {ok, {",",0,AccCount-1}};
+ (Key, Red, {AccSeparator,0,AccCount})
+ when is_tuple(Key) and is_integer(GroupLevel) ->
+ Json = lists:flatten(cjson:encode(
+ {obj, [{key, list_to_tuple(lists:sublist(tuple_to_list(Key), GroupLevel))},
+ {value, Red}]})),
+ Resp:write_chunk(AccSeparator ++ Json),
+ {ok, {",",0,AccCount-1}};
+ (Key, Red, {AccSeparator,0,AccCount}) ->
+ Json = lists:flatten(cjson:encode({obj, [{key, Key}, {value, Red}]})),
+ Resp:write_chunk(AccSeparator ++ Json),
+ {ok, {",",0,AccCount-1}}
+ end, {"", Skip, Count}),
+ Resp:write_chunk("]}"),
+ end_json_response(Resp).
+
handle_doc_request(Req, 'DELETE', _DbName, Db, DocId) ->
QueryRev = proplists:get_value("rev", Req:parse_qs()),
Etag = case Req:get_header_value("If-Match") of
@@ -667,6 +709,10 @@ parse_view_query(Req) ->
"Bad URL query value, number expected: skip=~s", [Value])),
throw({query_parse_error, Msg})
end;
+ {"group", "true"} ->
+ Args#view_query_args{group_level=exact};
+ {"group_level", LevelStr} ->
+ Args#view_query_args{group_level=list_to_integer(LevelStr)};
_ -> % unknown key
Msg = lists:flatten(io_lib:format(
"Bad URL query key:~s", [Key])),
diff --git a/src/couchdb/couch_view.erl b/src/couchdb/couch_view.erl
index d106fdc2..c44a9ba8 100644
--- a/src/couchdb/couch_view.erl
+++ b/src/couchdb/couch_view.erl
@@ -17,7 +17,7 @@
-export([start_link/1,fold/4,fold/5,less_json/2, start_update_loop/3, start_temp_update_loop/5]).
-export([init/1,terminate/2,handle_call/3,handle_cast/2,handle_info/2,code_change/3]).
--export([get_reduce_view/1, get_map_view/1,get_row_count/1,reduce_to_count/1, reduce/3]).
+-export([get_reduce_view/1, get_map_view/1,get_row_count/1,reduce_to_count/1, fold_reduce/7]).
-include("couch_db.hrl").
@@ -79,8 +79,8 @@ get_updated_group(Pid) ->
end.
get_row_count(#view{btree=Bt}) ->
- {ok, Reds} = couch_btree:partial_reduce(Bt, nil, nil),
- {ok, reduce_to_count(Reds)}.
+ {ok, {Count, _Reds}} = couch_btree:full_reduce(Bt),
+ {ok, Count}.
get_reduce_view({temp, DbName, Type, MapSrc, RedSrc}) ->
{ok, #group{views=[View]}} = get_updated_group(get_temp_updater(DbName, Type, MapSrc, RedSrc)),
@@ -98,16 +98,20 @@ get_reduce_view0(Name, Lang, [#view{reduce_funs=RedFuns}=View|Rest]) ->
N -> {ok, {reduce, N, Lang, View}}
end.
-reduce({temp_reduce, #view{btree=Bt}}, Key1, Key2) ->
- {ok, {_Count, [Reduction]}} = couch_btree:reduce(Bt, Key1, Key2),
- {ok, Reduction};
+fold_reduce({temp_reduce, #view{btree=Bt}}, Dir, StartKey, EndKey, GroupFun, Fun, Acc) ->
-reduce({reduce, NthRed, Lang, #view{btree=Bt, reduce_funs=RedFuns}}, Key1, Key2) ->
- {ok, PartialReductions} = couch_btree:partial_reduce(Bt, Key1, Key2),
+ WrapperFun = fun({GroupedKey, _}, PartialReds, Acc0) ->
+ {_, [Red]} = couch_btree:final_reduce(Bt, PartialReds),
+ Fun(GroupedKey, Red, Acc0)
+ end,
+ couch_btree:fold_reduce(Bt, Dir, StartKey, EndKey, GroupFun,
+ WrapperFun, Acc);
+
+fold_reduce({reduce, NthRed, Lang, #view{btree=Bt, reduce_funs=RedFuns}}, Dir, StartKey, EndKey, GroupFun, Fun, Acc) ->
PreResultPadding = lists:duplicate(NthRed - 1, []),
PostResultPadding = lists:duplicate(length(RedFuns) - NthRed, []),
{_Name, FunSrc} = lists:nth(NthRed,RedFuns),
- ReduceFun =
+ ReduceFun =
fun(reduce, KVs) ->
{ok, Reduced} = couch_query_servers:reduce(Lang, [FunSrc], KVs),
{0, PreResultPadding ++ Reduced ++ PostResultPadding};
@@ -116,8 +120,12 @@ reduce({reduce, NthRed, Lang, #view{btree=Bt, reduce_funs=RedFuns}}, Key1, Key2)
{ok, Reduced} = couch_query_servers:combine(Lang, [FunSrc], UserReds),
{0, PreResultPadding ++ Reduced ++ PostResultPadding}
end,
- {_, FinalReds} = couch_btree:final_reduce(ReduceFun, PartialReductions),
- {ok, lists:nth(NthRed, FinalReds)}.
+ WrapperFun = fun({GroupedKey, _}, PartialReds, Acc0) ->
+ {_, Reds} = couch_btree:final_reduce(ReduceFun, PartialReds),
+ Fun(GroupedKey, lists:nth(NthRed, Reds), Acc0)
+ end,
+ couch_btree:fold_reduce(Bt, Dir, StartKey, EndKey, GroupFun,
+ WrapperFun, Acc).
get_key_pos(_Key, [], _N) ->
0;
@@ -365,7 +373,7 @@ start_update_loop(RootDir, DbName, GroupId, NotifyPids) ->
Group =
case couch_file:open(FileName) of
{ok, Fd} ->
- case couch_file:read_header(Fd, <<$r, $c, $k, 0>>) of
+ case (catch couch_file:read_header(Fd, <<$r, $c, $k, 0>>)) of
{ok, ExistingDiskGroup} ->
% validate all the view definitions in the index are correct.
case reset_group(ExistingDiskGroup) == reset_group(DbGroup) of