From 486c354ba0dc930ef564198b61a5c60d471bc97a Mon Sep 17 00:00:00 2001
From: Kevin Lynx <kevinlynx@gmail.com>
Date: Fri, 2 Aug 2013 22:19:31 +0800
Subject: [PATCH] change sphinx torrent loading using an existing cursor

---
 src/sphinx_builder/sphinx_builder_sup.erl |  2 +-
 src/sphinx_builder/sphinx_torrent.erl     | 47 +++++++++++++++++------
 2 files changed, 36 insertions(+), 13 deletions(-)

diff --git a/src/sphinx_builder/sphinx_builder_sup.erl b/src/sphinx_builder/sphinx_builder_sup.erl
index 8e3bb0b..969c7d8 100644
--- a/src/sphinx_builder/sphinx_builder_sup.erl
+++ b/src/sphinx_builder/sphinx_builder_sup.erl
@@ -46,7 +46,7 @@ init([IP, Port, Count]) ->
 	config:start_link("sphinx_builder.config", fun() -> config_default() end),
 	Builder = {sphinx_builder, {sphinx_builder, start_link, [IP, Port, Count]}, permanent, 1000, worker, [sphinx_builder]},
 	Indexer = {sphinx_xml, {sphinx_xml, start_link, []}, permanent, 1000, worker, [sphinx_xml]},
-	Logger = {vlog, {vlog, start_link, ["log/sphinx_build.log", 1]}, permanent, 1000, worker, [vlog]},
+	Logger = {vlog, {vlog, start_link, ["log/sphinx_build.log", 0]}, permanent, 1000, worker, [vlog]},
 	Children = [Logger, Builder, Indexer],
     {ok, {Spec, Children}}.
 
diff --git a/src/sphinx_builder/sphinx_torrent.erl b/src/sphinx_builder/sphinx_torrent.erl
index 4c8f368..4e4d098 100644
--- a/src/sphinx_builder/sphinx_torrent.erl
+++ b/src/sphinx_builder/sphinx_torrent.erl
@@ -13,11 +13,12 @@
          terminate/2,
          code_change/3]).
 -export([start_link/3, get/0, try_times/0]).
+-export([do_load_torrents/2]). % disable warning only
 -define(DBNAME, torrents).
 -define(COLLNAME, hashes).
 -define(POOLNAME, db_pool).
 -define(WAIT_TIME, 30*1000).
--record(state, {offset = 0, max, try_times = 0, tors = []}).
+-record(state, {offset = 0, max, try_times = 0, tors = [], cursor}).
 
 start_link(IP, Port, Offset) ->
 	gen_server:start_link({local, srv_name()}, ?MODULE, [IP, Port, Offset], []).
@@ -38,12 +39,15 @@ init([IP, Port, Offset]) ->
 	{ok, #state{offset = Offset, max = Max}, 0}.
 
 handle_cast(load, State) ->
-	#state{offset = Skip, max = Max, tors = Tors} = State,
+	#state{cursor = Cursor, offset = Skip, max = Max, tors = Tors} = State,
 	Request = Max * 2 div 3,
 	?T(?FMT("request next ~p torrents", [Request])),
-	LoadTors = do_load_torrents(Skip, Request),
+	LoadTors = load_next_batch(Cursor, Request),
 	case length(LoadTors) of
-		0 -> timer:send_after(?WAIT_TIME, try_load);
+		0 -> 
+			?T(?FMT("no torrents in cursor ~p", [Cursor])),
+			mongo_cursor:close(Cursor),
+			timer:send_after(?WAIT_TIME, try_load);
 		_ -> ok
 	end,
 	?T(?FMT("load ~p torrents", [length(LoadTors)])),
@@ -56,14 +60,13 @@ handle_cast(stop, State) ->
 handle_info(try_load, State) ->
 	#state{offset = Skip, max = Max, try_times = Try} = State,
 	?T(?FMT("try load ~p torrents from ~p", [Max, Skip])),
-	LoadTors = do_load_torrents(Skip, Max),
-	LoadCnt = length(LoadTors),
-	NewTry = case LoadCnt > 0 of
-		true -> 0;
-		false -> timer:send_after(?WAIT_TIME, try_load), Try + 1
-	end,
-	?T(?FMT("load ~p torrents, try times ~p", [LoadCnt, NewTry])),
-	{noreply, State#state{offset = Skip + LoadCnt, tors = LoadTors, try_times = NewTry}};
+	case load_cursor_batch(Skip, Max) of
+		{} -> 
+			timer:send_after(?WAIT_TIME, try_load),
+			{noreply, State#state{try_times = Try + 1}};
+		{Cursor, R} ->
+			{noreply, State#state{try_times = 0, offset = Skip + length(R), tors = R, cursor = Cursor}}
+	end;
 
 handle_info(timeout, State) ->
 	self() ! try_load,
@@ -97,6 +100,26 @@ try_load_next(Tors, Max) when length(Tors) == Max div 3 ->
 try_load_next(_, _) ->
 	ok.
 
+load_cursor(Skip, Size) ->
+	Conn = mongo_pool:get(?POOLNAME),
+	mongo:do(safe, master, Conn, ?DBNAME, fun() ->
+		mongo:find(?COLLNAME, {}, {}, Skip, Size)
+	end).
+
+load_cursor_batch(Skip, Size) ->
+	Cursor = load_cursor(Skip, Size),
+	case load_next_batch(Cursor, Size) of
+		[] ->
+			mongo_cursor:close(Cursor), {};
+		R ->
+			{Cursor, R}
+	end.
+
+% will cause `get_more'
+load_next_batch(Cursor, Size) ->
+	mongo_cursor:take(Cursor, Size).
+
+% will cause lots of queries
 do_load_torrents(Skip, Size) ->
 	Conn = mongo_pool:get(?POOLNAME),
 	mongo:do(safe, master, Conn, ?DBNAME, fun() ->