Added concurrent open db limit and a LRU cache for closing old databases when limit reached (configurable via MaxDbsOpen var in couch.ini). Refactored db update code in couch_db.erl into couch_db_updater.erl.

git-svn-id: https://svn.apache.org/repos/asf/incubator/couchdb/trunk@682560 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 56 insertions, 43 deletions

diff --git a/src/couchdb/couch_view.erl b/src/couchdb/couch_view.erl
index 53cc4cda..a29a809c 100644
--- a/src/couchdb/couch_view.erl
+++ b/src/couchdb/couch_view.erl
@@ -57,22 +57,22 @@ get_updater(DbName, GroupId) ->
     Pid.
     
 get_updated_group(Pid) ->
-	Mref = erlang:monitor(process, Pid),
+    Mref = erlang:monitor(process, Pid),
     receive
-	{'DOWN', Mref, _, _, Reason} ->
-	    throw(Reason)
+    {'DOWN', Mref, _, _, Reason} ->
+        throw(Reason)
     after 0 ->
-	    Pid ! {self(), get_updated},
-	    receive
-    	{Pid, Response} ->
-    	    erlang:demonitor(Mref),
-    	    receive
-        		{'DOWN', Mref, _, _, _} -> ok
-        	    after 0 -> ok
-    	    end,
-    	    Response;
-    	{'DOWN', Mref, _, _, Reason} ->
-    	    throw(Reason)
+        Pid ! {self(), get_updated},
+        receive
+        {Pid, Response} ->
+            erlang:demonitor(Mref),
+            receive
+                {'DOWN', Mref, _, _, _} -> ok
+                after 0 -> ok
+            end,
+            Response;
+        {'DOWN', Mref, _, _, Reason} ->
+            throw(Reason)
         end
     end.
 
@@ -216,10 +216,7 @@ init(RootDir) ->
     {ok, #server{root_dir=RootDir}}.
 
 terminate(_Reason, _) ->
-    catch ets:delete(couch_views_by_name),
-    catch ets:delete(couch_views_by_updater),
-    catch ets:delete(couch_views_by_db),
-    catch ets:delete(couch_views_temp_fd_by_db).
+    ok.
 
 
 handle_call({start_temp_updater, DbName, Lang, MapSrc, RedSrc}, _From, #server{root_dir=Root}=Server) ->
@@ -317,7 +314,7 @@ code_change(_OldVsn, State, _Extra) ->
 
 start_temp_update_loop(DbName, Fd, Lang, MapSrc, RedSrc) ->
     NotifyPids = get_notify_pids(1000),
-    case couch_server:open(DbName) of
+    case couch_db:open(DbName, []) of
     {ok, Db} ->
         View = #view{map_names=["_temp"],
             id_num=0,
@@ -331,16 +328,20 @@ start_temp_update_loop(DbName, Fd, Lang, MapSrc, RedSrc) ->
             def_lang=Lang,
             id_btree=nil},
         Group2 = init_group(Db, Fd, Group,nil),
-        temp_update_loop(Group2, NotifyPids);
+        couch_db:monitor(Db),
+        couch_db:close(Db),
+        temp_update_loop(DbName, Group2, NotifyPids);
     Else ->
         exit(Else)
     end.
 
-temp_update_loop(Group, NotifyPids) ->
-    {ok, Group2} = update_group(Group),
+temp_update_loop(DbName, Group, NotifyPids) ->
+    {ok, Db} = couch_db:open(DbName, []),
+    {ok, Group2} = update_group(Group#group{db=Db}),
+    couch_db:close(Db),
     [Pid ! {self(), {ok, Group2}} || Pid <- NotifyPids],
     garbage_collect(),
-    temp_update_loop(Group2, get_notify_pids(10000)).
+    temp_update_loop(DbName, Group2, get_notify_pids(10000)).
 
 
 reset_group(#group{views=Views}=Group) ->
@@ -355,21 +356,21 @@ start_update_loop(RootDir, DbName, GroupId) ->
     
 start_update_loop(RootDir, DbName, GroupId, NotifyPids) ->
     {Db, Group} =
-    case (catch couch_server:open(DbName)) of
+    case (catch couch_db:open(DbName, [])) of
     {ok, Db0} ->
         case (catch couch_db:open_doc(Db0, GroupId)) of
         {ok, Doc} ->
             {Db0, design_doc_to_view_group(Doc)};
- 		Else ->
- 		    delete_index_file(RootDir, DbName, GroupId),
- 		    exit(Else)
- 		end;
- 	Else ->
- 	    delete_index_file(RootDir, DbName, GroupId),
- 	    exit(Else)
- 	end,
- 	FileName = RootDir ++ "/." ++ DbName ++ GroupId ++".view",
- 	Group2 =
+        Else ->
+            delete_index_file(RootDir, DbName, GroupId),
+            exit(Else)
+        end;
+    Else ->
+        delete_index_file(RootDir, DbName, GroupId),
+        exit(Else)
+    end,
+    FileName = RootDir ++ "/." ++ DbName ++ GroupId ++".view",
+    Group2 =
     case couch_file:open(FileName) of
     {ok, Fd} ->
         Sig = Group#group.sig,
@@ -386,7 +387,8 @@ start_update_loop(RootDir, DbName, GroupId, NotifyPids) ->
         Error    -> throw(Error)
         end
     end,
-    
+    couch_db:monitor(Db),
+    couch_db:close(Db),
     update_loop(RootDir, DbName, GroupId, Group2, NotifyPids).
 
 reset_file(Db, Fd, DbName, #group{sig=Sig,name=Name} = Group) ->
@@ -396,14 +398,22 @@ reset_file(Db, Fd, DbName, #group{sig=Sig,name=Name} = Group) ->
     init_group(Db, Fd, reset_group(Group), nil).
 
 update_loop(RootDir, DbName, GroupId, #group{sig=Sig,fd=Fd}=Group, NotifyPids) ->
-    try update_group(Group) of
-    {ok, Group2} ->    
+    {ok, Db}= couch_db:open(DbName, []),
+    Result =
+    try
+        update_group(Group#group{db=Db})
+    catch
+        throw: restart -> restart
+    after
+        couch_db:close(Db)
+    end,
+    case Result of
+    {ok, Group2} ->
         HeaderData = {Sig, get_index_header_data(Group2)},
         ok = couch_file:write_header(Fd, <<$r, $c, $k, 0>>, HeaderData),
         [Pid ! {self(), {ok, Group2}} || Pid <- NotifyPids],
         garbage_collect(),
-        update_loop(RootDir, DbName, GroupId, Group2, get_notify_pids(100000))
-    catch
+        update_loop(RootDir, DbName, GroupId, Group2, get_notify_pids(100000));
     restart ->
         couch_file:close(Group#group.fd),
         start_update_loop(RootDir, DbName, GroupId, NotifyPids ++ get_notify_pids())
@@ -414,20 +424,23 @@ get_notify_pids(Wait) ->
     receive
     {Pid, get_updated} ->
         [Pid | get_notify_pids()];
+    {'DOWN', _MonitorRef, _Type, _Pid, _Info} ->
+        ?LOG_DEBUG("View monitor received parent db shutdown notification. Shutting down instance.", []),
+        exit(normal);
     Else ->
         ?LOG_ERROR("Unexpected message in view updater: ~p", [Else]),
         exit({error, Else})
     after Wait ->
         exit(wait_timeout)
-	end.
+    end.
 % then keep getting all available and return.
 get_notify_pids() ->
     receive
     {Pid, get_updated} ->
         [Pid | get_notify_pids()]
-	after 0 ->
-	    []
-	end.
+    after 0 ->
+        []
+    end.
     
 update_group(#group{db=Db,current_seq=CurrentSeq, views=Views}=Group) ->
     ViewEmptyKVs = [{View, []} || View <- Views],