From b5c7b8bcfff3e361507b8ddb64edc94f90c13514 Mon Sep 17 00:00:00 2001
From: "Damien F. Katz" <damien@apache.org>
Date: Fri, 23 May 2008 16:51:46 +0000
Subject: fix for bug with reusing map btree indexes when multiple views have
 the same map function

git-svn-id: https://svn.apache.org/repos/asf/incubator/couchdb/trunk@659596 13f79535-47bb-0310-9956-ffa450edef68
---
 share/server/main.js        |  5 ++--
 src/couchdb/couch_btree.erl | 56 +++++++++++++++++++++++----------------------
 src/couchdb/couch_view.erl  |  4 ++--
 3 files changed, 34 insertions(+), 31 deletions(-)

diff --git a/share/server/main.js b/share/server/main.js
index 43660c7b..a62ed1ff 100644
--- a/share/server/main.js
+++ b/share/server/main.js
@@ -104,11 +104,12 @@ while (cmd = eval(readline())) {
         var values = null;
         var reduceFuns = cmd[1];
         var is_combine = false;
+        
         if (cmd[0] == "reduce") {
           var kvs = cmd[2];
           keys = new Array(kvs.length);
           values = new Array(kvs.length);
-          for (var i = 0; i < kvs.length; i++) {
+          for(var i = 0; i < kvs.length; i++) {
               keys[i] = kvs[i][0];
               values[i] = kvs[i][1];
           }
@@ -122,7 +123,7 @@ while (cmd = eval(readline())) {
         }
 
         var reductions = new Array(funs.length);
-        for (var i = 0; i < reduceFuns.length; i++) {
+        for(var i = 0; i < reduceFuns.length; i++) {
           try {
             reductions[i] = reduceFuns[i](keys, values, is_combine);
           } catch (err) {
diff --git a/src/couchdb/couch_btree.erl b/src/couchdb/couch_btree.erl
index 57013ee9..3d95ae5c 100644
--- a/src/couchdb/couch_btree.erl
+++ b/src/couchdb/couch_btree.erl
@@ -390,40 +390,42 @@ 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) ->
     case get_node(Bt, P) of
     {kp_node, NodeList} ->
         collect_kp_node(Bt, NodeList, KeyStart, KeyEnd);
     {kv_node, KVs} ->
-        GTEKeyStartKVs =
-        case KeyStart of
-        nil ->
-            KVs;
-        _ ->
-            lists:dropwhile(
-                fun({Key,_}) ->
-                    less(Bt, Key, KeyStart)
-                end, KVs)
-        end,
-        KVs2 =
-        case KeyEnd of
-        nil ->
-            GTEKeyStartKVs;
-        _ ->
-            lists:dropwhile(
-                fun({Key,_}) -> 
-                    less(Bt, KeyEnd, Key)
-                end, lists:reverse(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], []}
-        end
+        collect_kv_node(Bt, {P,R}, KVs, KeyStart, KeyEnd)
     end.
 
-
+collect_kv_node(Bt, {P,R}, KVs, KeyStart, KeyEnd) ->
+    GTEKeyStartKVs =
+    case KeyStart of
+    nil ->
+        KVs;
+    _ ->
+        lists:dropwhile(fun({Key,_}) -> less(Bt, Key, KeyStart) end, KVs)
+    end,
+    KVs2 =
+    case KeyEnd of
+    nil ->
+        GTEKeyStartKVs;
+    _ ->
+        lists:dropwhile(
+            fun({Key,_}) -> 
+                less(Bt, KeyEnd, Key)
+            end, lists:reverse(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], []}
+    end.
+        
+        
 collect_kp_node(Bt, NodeList, KeyStart, KeyEnd) ->   
     Nodes =
     case KeyStart of
diff --git a/src/couchdb/couch_view.erl b/src/couchdb/couch_view.erl
index b14f4564..d106fdc2 100644
--- a/src/couchdb/couch_view.erl
+++ b/src/couchdb/couch_view.erl
@@ -116,8 +116,8 @@ 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,
-    {_, [FinalReduction]} = couch_btree:final_reduce(ReduceFun, PartialReductions),
-    {ok, FinalReduction}.
+    {_, FinalReds} = couch_btree:final_reduce(ReduceFun, PartialReductions),
+    {ok, lists:nth(NthRed, FinalReds)}.
         
 get_key_pos(_Key, [], _N) ->
     0;
-- 
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