mod_mam_mnesia: Use transactions when writing

Let mod_mam_mnesia use transactions when storing or deleting messages.

If old messages of a user are to be removed, delete the user's archive
and rewrite it from scratch, as that seems to be much faster than
removing individual records with delete_object/1.

Closes #1065.

diff --git a/src/mod_mam_mnesia.erl b/src/mod_mam_mnesia.erl
index 007ef5ebabd189232e8c0ef9fc04f26fe52f523e..1e1f20c9ada6ad92e0cb54c109cd9758f1921bee 100644 (file)
--- a/src/mod_mam_mnesia.erl
+++ b/src/mod_mam_mnesia.erl
@@ -16,6 +16,7 @@
 
 -include_lib("stdlib/include/ms_transform.hrl").
 -include("jlib.hrl").
+-include("logger.hrl").
 -include("mod_mam.hrl").
 
 -define(BIN_GREATER_THAN(A, B),
@@ -49,16 +50,34 @@ remove_room(_LServer, LName, LHost) ->
     remove_user(LName, LHost).
 
 delete_old_messages(global, TimeStamp, Type) ->
-    MS = ets:fun2ms(fun(#archive_msg{timestamp = MsgTS,
-                                    type = MsgType} = Msg)
-                         when MsgTS < TimeStamp,
-                              MsgType == Type orelse Type == all ->
-                           Msg
-                   end),
-    OldMsgs = mnesia:dirty_select(archive_msg, MS),
-    lists:foreach(fun(Rec) ->
-                         ok = mnesia:dirty_delete_object(Rec)
-                 end, OldMsgs).
+    delete_old_user_messages(mnesia:dirty_first(archive_msg), TimeStamp, Type).
+
+delete_old_user_messages('$end_of_table', _TimeStamp, _Type) ->
+    ok;
+delete_old_user_messages(User, TimeStamp, Type) ->
+    F = fun() ->
+               Msgs = mnesia:read(archive_msg, User),
+               Keep = lists:filter(
+                        fun(#archive_msg{timestamp = MsgTS,
+                                         type = MsgType}) ->
+                                MsgTS >= TimeStamp orelse (Type /= all andalso
+                                                           Type /= MsgType)
+                        end, Msgs),
+               if length(Keep) < length(Msgs) ->
+                       mnesia:delete({archive_msg, User}),
+                       lists:foreach(fun(Msg) -> mnesia:write(Msg) end, Keep);
+                  true ->
+                       ok
+               end
+       end,
+    case mnesia:transaction(F) of
+       {atomic, ok} ->
+           delete_old_user_messages(mnesia:dirty_next(archive_msg, User),
+                                    TimeStamp, Type);
+       {aborted, Err} ->
+           ?ERROR_MSG("Cannot delete old MAM messages: ~s", [Err]),
+           Err
+    end.
 
 extended_fields() ->
     [].
@@ -67,18 +86,22 @@ store(Pkt, _, {LUser, LServer}, Type, Peer, Nick, _Dir) ->
     LPeer = {PUser, PServer, _} = jid:tolower(Peer),
     TS = p1_time_compat:timestamp(),
     ID = jlib:integer_to_binary(now_to_usec(TS)),
-    case mnesia:dirty_write(
-          #archive_msg{us = {LUser, LServer},
-                       id = ID,
-                       timestamp = TS,
-                       peer = LPeer,
-                       bare_peer = {PUser, PServer, <<>>},
-                       type = Type,
-                       nick = Nick,
-                       packet = Pkt}) of
-       ok ->
+    F = fun() ->
+               mnesia:write(#archive_msg{us = {LUser, LServer},
+                                         id = ID,
+                                         timestamp = TS,
+                                         peer = LPeer,
+                                         bare_peer = {PUser, PServer, <<>>},
+                                         type = Type,
+                                         nick = Nick,
+                                         packet = Pkt})
+       end,
+    case mnesia:transaction(F) of
+       {atomic, ok} ->
            {ok, ID};
-       Err ->
+       {aborted, Err} ->
+           ?ERROR_MSG("Cannot add message to MAM archive of ~s@~s: ~s",
+                      [LUser, LServer, Err]),
            Err
     end.