From 81bdbed444df2cbcf3cdb32f7d4a74019de06454 Mon Sep 17 00:00:00 2001
From: Adam Kocoloski <adam@cloudant.com>
Date: Wed, 11 Aug 2010 15:22:33 -0400
Subject: reorganize couch .erl and driver code into rebar layout

---
 apps/couch/src/couch_view_compactor.erl | 98 +++++++++++++++++++++++++++++++++
 1 file changed, 98 insertions(+)
 create mode 100644 apps/couch/src/couch_view_compactor.erl

(limited to 'apps/couch/src/couch_view_compactor.erl')

diff --git a/apps/couch/src/couch_view_compactor.erl b/apps/couch/src/couch_view_compactor.erl
new file mode 100644
index 00000000..895556bf
--- /dev/null
+++ b/apps/couch/src/couch_view_compactor.erl
@@ -0,0 +1,98 @@
+% 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_view_compactor).
+
+-include ("couch_db.hrl").
+
+-export([start_compact/2]).
+
+%% @spec start_compact(DbName::binary(), GroupId:binary()) -> ok
+%% @doc Compacts the views.  GroupId must not include the _design/ prefix
+start_compact(DbName, GroupId) ->
+    Pid = couch_view:get_group_server(DbName, <<"_design/",GroupId/binary>>),
+    gen_server:cast(Pid, {start_compact, fun compact_group/2}).
+
+%%=============================================================================
+%% internal functions
+%%=============================================================================
+
+%% @spec compact_group(Group, NewGroup) -> ok
+compact_group(Group, EmptyGroup) ->
+    #group{
+        current_seq = Seq,
+        id_btree = IdBtree,
+        name = GroupId,
+        views = Views
+    } = Group,
+
+    #group{
+        db = Db,
+        id_btree = EmptyIdBtree,
+        views = EmptyViews
+    } = EmptyGroup,
+
+    {ok, {Count, _}} = couch_btree:full_reduce(Db#db.fulldocinfo_by_id_btree),
+
+    <<"_design", ShortName/binary>> = GroupId,
+    DbName = couch_db:name(Db),
+    TaskName = <<DbName/binary, ShortName/binary>>,
+    couch_task_status:add_task(<<"View Group Compaction">>, TaskName, <<"">>),
+
+    Fun = fun(KV, {Bt, Acc, TotalCopied}) ->
+        if TotalCopied rem 10000 =:= 0 ->
+            couch_task_status:update("Copied ~p of ~p Ids (~p%)",
+                [TotalCopied, Count, (TotalCopied*100) div Count]),
+            {ok, Bt2} = couch_btree:add(Bt, lists:reverse([KV|Acc])),
+            {ok, {Bt2, [], TotalCopied+1}};
+        true ->
+            {ok, {Bt, [KV|Acc], TotalCopied+1}}
+        end
+    end,
+    {ok, _, {Bt3, Uncopied, _Total}} = couch_btree:foldl(IdBtree, Fun,
+        {EmptyIdBtree, [], 0}),
+    {ok, NewIdBtree} = couch_btree:add(Bt3, lists:reverse(Uncopied)),
+
+    NewViews = lists:map(fun({View, EmptyView}) ->
+        compact_view(View, EmptyView)
+    end, lists:zip(Views, EmptyViews)),
+
+    NewGroup = EmptyGroup#group{
+        id_btree=NewIdBtree,
+        views=NewViews,
+        current_seq=Seq
+    },
+
+    Pid = couch_view:get_group_server(DbName, GroupId),
+    gen_server:cast(Pid, {compact_done, NewGroup}).
+
+%% @spec compact_view(View, EmptyView, Retry) -> CompactView
+compact_view(View, EmptyView) ->
+    {ok, Count} = couch_view:get_row_count(View),
+
+    %% Key is {Key,DocId}
+    Fun = fun(KV, {Bt, Acc, TotalCopied}) ->
+        if TotalCopied rem 10000 =:= 0 ->
+            couch_task_status:update("View #~p: copied ~p of ~p KVs (~p%)",
+                [View#view.id_num, TotalCopied, Count, (TotalCopied*100) div Count]),
+            {ok, Bt2} = couch_btree:add(Bt, lists:reverse([KV|Acc])),
+            {ok, {Bt2, [], TotalCopied + 1}};
+        true ->
+            {ok, {Bt, [KV|Acc], TotalCopied + 1}}
+        end
+    end,
+
+    {ok, _, {Bt3, Uncopied, _Total}} = couch_btree:foldl(View#view.btree, Fun,
+        {EmptyView#view.btree, [], 0}),
+    {ok, NewBt} = couch_btree:add(Bt3, lists:reverse(Uncopied)),
+    EmptyView#view{btree = NewBt}.
+
-- 
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