Clean mod_mam.erl from DB specific code

4 files changed, 561 insertions, 477 deletions

diff --git a/src/mod_mam.erl b/src/mod_mam.erl
index 862adee99..098ee8967 100644
--- a/src/mod_mam.erl
+++ b/src/mod_mam.erl
@@ -35,41 +35,37 @@
 
 -export([user_send_packet/4, user_receive_packet/5,
 	 process_iq_v0_2/3, process_iq_v0_3/3, disco_sm_features/5,
-	 remove_user/2, remove_user/3, mod_opt_type/1, muc_process_iq/4,
+	 remove_user/2, remove_room/3, mod_opt_type/1, muc_process_iq/4,
 	 muc_filter_message/5, message_is_archived/5, delete_old_messages/2,
-	 get_commands_spec/0]).
+	 get_commands_spec/0, msg_to_el/4]).
 
--include_lib("stdlib/include/ms_transform.hrl").
 -include("jlib.hrl").
 -include("logger.hrl").
 -include("mod_muc_room.hrl").
 -include("ejabberd_commands.hrl").
+-include("mod_mam.hrl").
 
 -define(DEF_PAGE_SIZE, 50).
 -define(MAX_PAGE_SIZE, 250).
 
--define(BIN_GREATER_THAN(A, B),
-	((A > B andalso byte_size(A) == byte_size(B))
-	 orelse byte_size(A) > byte_size(B))).
--define(BIN_LESS_THAN(A, B),
-	((A < B andalso byte_size(A) == byte_size(B))
-	 orelse byte_size(A) < byte_size(B))).
-
--record(archive_msg,
-	{us = {<<"">>, <<"">>}                :: {binary(), binary()} | '$2',
-	 id = <<>>                            :: binary() | '_',
-	 timestamp = p1_time_compat:timestamp() :: erlang:timestamp() | '_' | '$1',
-	 peer = {<<"">>, <<"">>, <<"">>}      :: ljid() | '_' | '$3' | undefined,
-	 bare_peer = {<<"">>, <<"">>, <<"">>} :: ljid() | '_' | '$3',
-	 packet = #xmlel{}                    :: xmlel() | '_',
-	 nick = <<"">>                        :: binary(),
-	 type = chat                          :: chat | groupchat}).
-
--record(archive_prefs,
-	{us = {<<"">>, <<"">>} :: {binary(), binary()},
-	 default = never       :: never | always | roster,
-	 always = []           :: [ljid()],
-	 never = []            :: [ljid()]}).
+-callback init(binary(), gen_mod:opts()) -> any().
+-callback remove_user(binary(), binary()) -> any().
+-callback remove_room(binary(), binary(), binary()) -> any().
+-callback delete_old_messages(binary() | global,
+			      erlang:timestamp(),
+			      all | chat | groupchat) -> any().
+-callback extended_fields() -> [xmlel()].
+-callback store(xmlel(), binary(), {binary(), binary()}, chat | groupchat,
+		jid(), binary(), recv | send) -> {ok, binary()} | any().
+-callback write_prefs(binary(), binary(), #archive_prefs{}, binary()) -> ok | any().
+-callback get_prefs(binary(), binary()) -> {ok, #archive_prefs{}} | error.
+-callback select(binary(), jid(), jid(),
+		 none | erlang:timestamp(),
+		 none | erlang:timestamp(),
+		 none | ljid() | {text, binary()},
+		 none | #rsm_in{},
+		 chat | groupchat) ->
+    {[{binary(), non_neg_integer(), xmlel()}], boolean(), non_neg_integer()}.
 
 %%%===================================================================
 %%% API
@@ -77,9 +73,9 @@
 start(Host, Opts) ->
     IQDisc = gen_mod:get_opt(iqdisc, Opts, fun gen_iq_handler:check_type/1,
 			     one_queue),
-    DBType = gen_mod:db_type(Host, Opts),
-    init_db(DBType, Host),
-    init_cache(DBType, Opts),
+    Mod = gen_mod:db_mod(Host, Opts, ?MODULE),
+    Mod:init(Host, Opts),
+    init_cache(Opts),
     gen_iq_handler:add_iq_handler(ejabberd_local, Host,
 				  ?NS_MAM_TMP, ?MODULE, process_iq_v0_2, IQDisc),
     gen_iq_handler:add_iq_handler(ejabberd_sm, Host,
@@ -120,18 +116,7 @@ start(Host, Opts) ->
     ejabberd_commands:register_commands(get_commands_spec()),
     ok.
 
-init_db(mnesia, _Host) ->
-    mnesia:create_table(archive_msg,
-			[{disc_only_copies, [node()]},
-			 {type, bag},
-			 {attributes, record_info(fields, archive_msg)}]),
-    mnesia:create_table(archive_prefs,
-			[{disc_only_copies, [node()]},
-			 {attributes, record_info(fields, archive_prefs)}]);
-init_db(_, _) ->
-    ok.
-
-init_cache(_DBType, Opts) ->
+init_cache(Opts) ->
     MaxSize = gen_mod:get_opt(cache_size, Opts,
 			      fun(I) when is_integer(I), I>0 -> I end,
 			      1000),
@@ -179,24 +164,14 @@ stop(Host) ->
 remove_user(User, Server) ->
     LUser = jid:nodeprep(User),
     LServer = jid:nameprep(Server),
-    remove_user(LUser, LServer,
-		gen_mod:db_type(LServer, ?MODULE)).
+    Mod = gen_mod:db_mod(LServer, ?MODULE),
+    Mod:remove_user(LUser, LServer).
 
-remove_user(LUser, LServer, mnesia) ->
-    US = {LUser, LServer},
-    F = fun () ->
-		mnesia:delete({archive_msg, US}),
-		mnesia:delete({archive_prefs, US})
-	end,
-    mnesia:transaction(F);
-remove_user(LUser, LServer, odbc) ->
-    SUser = ejabberd_odbc:escape(LUser),
-    ejabberd_odbc:sql_query(
-      LServer,
-      [<<"delete from archive where username='">>, SUser, <<"';">>]),
-    ejabberd_odbc:sql_query(
-      LServer,
-      [<<"delete from archive_prefs where username='">>, SUser, <<"';">>]).
+remove_room(LServer, Name, Host) ->
+    LName = jid:nodeprep(Name),
+    LHost = jid:nameprep(Host),
+    Mod = gen_mod:db_mod(LServer, ?MODULE),
+    Mod:remove_room(LServer, LName, LHost).
 
 user_receive_packet(Pkt, C2SState, JID, Peer, To) ->
     LUser = JID#jid.luser,
@@ -343,10 +318,10 @@ message_is_archived(false, C2SState, Peer,
 	      if_enabled ->
 		  get_prefs(LUser, LServer);
 	      on_request ->
-		  DBType = gen_mod:db_type(LServer, ?MODULE),
+		  Mod = gen_mod:db_mod(LServer, ?MODULE),
 		  cache_tab:lookup(archive_prefs, {LUser, LServer},
 				   fun() ->
-					   get_prefs(LUser, LServer, DBType)
+					   Mod:get_prefs(LUser, LServer)
 				   end);
 	      never ->
 		  error
@@ -365,21 +340,19 @@ delete_old_messages(TypeBin, Days) when TypeBin == <<"chat">>;
     Diff = Days * 24 * 60 * 60 * 1000000,
     TimeStamp = usec_to_now(p1_time_compat:system_time(micro_seconds) - Diff),
     Type = jlib:binary_to_atom(TypeBin),
-    {Results, _} =
-	lists:foldl(fun(Host, {Results, MnesiaDone}) ->
-			    case {gen_mod:db_type(Host, ?MODULE), MnesiaDone} of
-				{mnesia, true} ->
-				    {Results, true};
-				{mnesia, false} ->
-				    Res = delete_old_messages(TimeStamp, Type,
-							      global, mnesia),
-				    {[Res|Results], true};
-				{DBType, _} ->
-				    Res = delete_old_messages(TimeStamp, Type,
-							      Host, DBType),
-				    {[Res|Results], MnesiaDone}
-			    end
-		    end, {[], false}, ?MYHOSTS),
+    DBTypes = lists:usort(
+		lists:map(
+		  fun(Host) ->
+			  case gen_mod:db_type(Host, ?MODULE) of
+			      odbc -> {odbc, Host};
+			      Other -> {Other, global}
+			  end
+		  end, ?MYHOSTS)),
+    Results = lists:map(
+		fun({DBType, ServerHost}) ->
+			Mod = gen_mod:db_mod(DBType, ?MODULE),
+			Mod:delete_old_messages(ServerHost, TimeStamp, Type)
+		end, DBTypes),
     case lists:filter(fun(Res) -> Res /= ok end, Results) of
 	[] -> ok;
 	[NotOk|_] -> NotOk
@@ -387,21 +360,6 @@ delete_old_messages(TypeBin, Days) when TypeBin == <<"chat">>;
 delete_old_messages(_TypeBin, _Days) ->
     unsupported_type.
 
-delete_old_messages(TimeStamp, Type, global, mnesia) ->
-    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_messages(_TimeStamp, _Type, _Host, _DBType) ->
-    %% TODO
-    not_implemented.
-
 %%%===================================================================
 %%% Internal functions
 %%%===================================================================
@@ -427,15 +385,9 @@ process_iq(LServer, #iq{sub_el = #xmlel{attrs = Attrs}} = IQ) ->
 		    #xmlel{name = <<"field">>,
 			   attrs = [{<<"type">>, <<"text-single">>},
 				    {<<"var">>, <<"end">>}]}],
-    Fields = case gen_mod:db_type(LServer, ?MODULE) of
-		 odbc ->
-		     WithText = #xmlel{name = <<"field">>,
-				       attrs = [{<<"type">>, <<"text-single">>},
-						{<<"var">>, <<"withtext">>}]},
-		     [WithText|CommonFields];
-		 _ ->
-		     CommonFields
-	     end,
+    Mod = gen_mod:db_mod(LServer, ?MODULE),
+    ExtendedFields = Mod:extended_fields(),
+    Fields = ExtendedFields ++ CommonFields,
     Form = #xmlel{name = <<"x">>,
 		  attrs = [{<<"xmlns">>, ?NS_XDATA}, {<<"type">>, <<"form">>}],
 		  children = Fields},
@@ -715,8 +667,8 @@ store_msg(C2SState, Pkt, LUser, LServer, Peer, Dir) ->
     case should_archive_peer(C2SState, Prefs, Peer) of
 	true ->
 	    US = {LUser, LServer},
-	    store(Pkt, LServer, US, chat, Peer, <<"">>, Dir,
-		  gen_mod:db_type(LServer, ?MODULE));
+	    Mod = gen_mod:db_mod(LServer, ?MODULE),
+	    Mod:store(Pkt, LServer, US, chat, Peer, <<"">>, Dir);
 	false ->
 	    pass
     end.
@@ -726,101 +678,26 @@ store_muc(MUCState, Pkt, RoomJID, Peer, Nick) ->
 	true ->
 	    LServer = MUCState#state.server_host,
 	    {U, S, _} = jid:tolower(RoomJID),
-	    store(Pkt, LServer, {U, S}, groupchat, Peer, Nick, recv,
-		  gen_mod:db_type(LServer, ?MODULE));
+	    Mod = gen_mod:db_mod(LServer, ?MODULE),
+	    Mod:store(Pkt, LServer, {U, S}, groupchat, Peer, Nick, recv);
 	false ->
 	    pass
     end.
 
-store(Pkt, _, {LUser, LServer}, Type, Peer, Nick, _Dir, mnesia) ->
-    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 ->
-	    {ok, ID};
-	Err ->
-	    Err
-    end;
-store(Pkt, LServer, {LUser, LHost}, Type, Peer, Nick, _Dir, odbc) ->
-    TSinteger = p1_time_compat:system_time(micro_seconds),
-    ID = TS = jlib:integer_to_binary(TSinteger),
-    SUser = case Type of
-		chat -> LUser;
-		groupchat -> jid:to_string({LUser, LHost, <<>>})
-	    end,
-    BarePeer = jid:to_string(
-		 jid:tolower(
-		   jid:remove_resource(Peer))),
-    LPeer = jid:to_string(
-	      jid:tolower(Peer)),
-    XML = fxml:element_to_binary(Pkt),
-    Body = fxml:get_subtag_cdata(Pkt, <<"body">>),
-    case ejabberd_odbc:sql_query(
-	    LServer,
-	    [<<"insert into archive (username, timestamp, "
-		    "peer, bare_peer, xml, txt, kind, nick) values (">>,
-		<<"'">>, ejabberd_odbc:escape(SUser), <<"', ">>,
-		<<"'">>, TS, <<"', ">>,
-		<<"'">>, ejabberd_odbc:escape(LPeer), <<"', ">>,
-		<<"'">>, ejabberd_odbc:escape(BarePeer), <<"', ">>,
-		<<"'">>, ejabberd_odbc:escape(XML), <<"', ">>,
-		<<"'">>, ejabberd_odbc:escape(Body), <<"', ">>,
-		<<"'">>, jlib:atom_to_binary(Type), <<"', ">>,
-		<<"'">>, ejabberd_odbc:escape(Nick), <<"');">>]) of
-	{updated, _} ->
-	    {ok, ID};
-	Err ->
-	    Err
-    end.
-
 write_prefs(LUser, LServer, Host, Default, Always, Never) ->
-    DBType = case gen_mod:db_type(Host, ?MODULE) of
-		 odbc -> {odbc, Host};
-		 DB -> DB
-	     end,
     Prefs = #archive_prefs{us = {LUser, LServer},
 			   default = Default,
 			   always = Always,
 			   never = Never},
+    Mod = gen_mod:db_mod(Host, ?MODULE),
     cache_tab:dirty_insert(
       archive_prefs, {LUser, LServer}, Prefs,
-      fun() ->  write_prefs(LUser, LServer, Prefs, DBType) end).
-
-write_prefs(_LUser, _LServer, Prefs, mnesia) ->
-    mnesia:dirty_write(Prefs);
-write_prefs(LUser, _LServer, #archive_prefs{default = Default,
-					   never = Never,
-					   always = Always},
-	    {odbc, Host}) ->
-    SUser = ejabberd_odbc:escape(LUser),
-    SDefault = erlang:atom_to_binary(Default, utf8),
-    SAlways = ejabberd_odbc:encode_term(Always),
-    SNever = ejabberd_odbc:encode_term(Never),
-    case update(Host, <<"archive_prefs">>,
-		[<<"username">>, <<"def">>, <<"always">>, <<"never">>],
-		[SUser, SDefault, SAlways, SNever],
-		[<<"username='">>, SUser, <<"'">>]) of
-	{updated, _} ->
-	    ok;
-	Err ->
-	    Err
-    end.
+      fun() ->  Mod:write_prefs(LUser, LServer, Prefs, Host) end).
 
 get_prefs(LUser, LServer) ->
-    DBType = gen_mod:db_type(LServer, ?MODULE),
+    Mod = gen_mod:db_mod(LServer, ?MODULE),
     Res = cache_tab:lookup(archive_prefs, {LUser, LServer},
-			   fun() -> get_prefs(LUser, LServer,
-					      DBType)
-			   end),
+			   fun() -> Mod:get_prefs(LUser, LServer) end),
     case Res of
 	{ok, Prefs} ->
 	    Prefs;
@@ -842,31 +719,6 @@ get_prefs(LUser, LServer) ->
 	    end
     end.
 
-get_prefs(LUser, LServer, mnesia) ->
-    case mnesia:dirty_read(archive_prefs, {LUser, LServer}) of
-	[Prefs] ->
-	    {ok, Prefs};
-	_ ->
-	    error
-    end;
-get_prefs(LUser, LServer, odbc) ->
-    case ejabberd_odbc:sql_query(
-	   LServer,
-	   [<<"select def, always, never from archive_prefs ">>,
-	    <<"where username='">>,
-	    ejabberd_odbc:escape(LUser), <<"';">>]) of
-	{selected, _, [[SDefault, SAlways, SNever]]} ->
-	    Default = erlang:binary_to_existing_atom(SDefault, utf8),
-	    Always = ejabberd_odbc:decode_term(SAlways),
-	    Never = ejabberd_odbc:decode_term(SNever),
-	    {ok, #archive_prefs{us = {LUser, LServer},
-		    default = Default,
-		    always = Always,
-		    never = Never}};
-	_ ->
-	    error
-    end.
-
 prefs_el(Default, Always, Never, NS) ->
     Default1 = jlib:atom_to_binary(Default),
     JFun = fun(L) ->
@@ -890,11 +742,10 @@ maybe_activate_mam(LUser, LServer) ->
 					 false),
     case ActivateOpt of
 	true ->
+	    Mod = gen_mod:db_mod(LServer, ?MODULE),
 	    Res = cache_tab:lookup(archive_prefs, {LUser, LServer},
 				   fun() ->
-					   get_prefs(LUser, LServer,
-						     gen_mod:db_type(LServer,
-								     ?MODULE))
+					   Mod:get_prefs(LUser, LServer)
 				   end),
 	    case Res of
 		{ok, _Prefs} ->
@@ -912,31 +763,22 @@ maybe_activate_mam(LUser, LServer) ->
     end.
 
 select_and_send(LServer, From, To, Start, End, With, RSM, IQ, MsgType) ->
-    DBType = case gen_mod:db_type(LServer, ?MODULE) of
-		 odbc -> {odbc, LServer};
-		 DB -> DB
-	     end,
-    select_and_send(LServer, From, To, Start, End, With, RSM, IQ,
-		    MsgType, DBType).
-
-select_and_send(LServer, From, To, Start, End, With, RSM, IQ, MsgType, DBType) ->
     {Msgs, IsComplete, Count} = select_and_start(LServer, From, To, Start, End,
-						 With, RSM, MsgType, DBType),
+						 With, RSM, MsgType),
     SortedMsgs = lists:keysort(2, Msgs),
     send(From, To, SortedMsgs, RSM, Count, IsComplete, IQ).
 
-select_and_start(LServer, From, To, Start, End, With, RSM, MsgType, DBType) ->
+select_and_start(LServer, From, To, Start, End, With, RSM, MsgType) ->
     case MsgType of
 	chat ->
-	    select(LServer, From, From, Start, End, With, RSM, MsgType, DBType);
+	    select(LServer, From, From, Start, End, With, RSM, MsgType);
 	{groupchat, _Role, _MUCState} ->
-	    select(LServer, From, To, Start, End, With, RSM, MsgType, DBType)
+	    select(LServer, From, To, Start, End, With, RSM, MsgType)
     end.
 
 select(_LServer, JidRequestor, JidArchive, Start, End, _With, RSM,
        {groupchat, _Role, #state{config = #config{mam = false},
-				 history = History}} = MsgType,
-       _DBType) ->
+				 history = History}} = MsgType) ->
     #lqueue{len = L, queue = Q} = History,
     {Msgs0, _} =
 	lists:mapfoldl(
@@ -970,81 +812,9 @@ select(_LServer, JidRequestor, JidArchive, Start, End, _With, RSM,
 	_ ->
 	    {Msgs, true, L}
     end;
-select(_LServer, JidRequestor,
-       #jid{luser = LUser, lserver = LServer} = JidArchive,
-       Start, End, With, RSM, MsgType, mnesia) ->
-    MS = make_matchspec(LUser, LServer, Start, End, With),
-    Msgs = mnesia:dirty_select(archive_msg, MS),
-    SortedMsgs = lists:keysort(#archive_msg.timestamp, Msgs),
-    {FilteredMsgs, IsComplete} = filter_by_rsm(SortedMsgs, RSM),
-    Count = length(Msgs),
-    {lists:map(
-       fun(Msg) ->
-	       {Msg#archive_msg.id,
-		jlib:binary_to_integer(Msg#archive_msg.id),
-		msg_to_el(Msg, MsgType, JidRequestor, JidArchive)}
-       end, FilteredMsgs), IsComplete, Count};
-select(LServer, JidRequestor, #jid{luser = LUser} = JidArchive,
-       Start, End, With, RSM, MsgType, {odbc, Host}) ->
-    User = case MsgType of
-	       chat -> LUser;
-	       {groupchat, _Role, _MUCState} -> jid:to_string(JidArchive)
-	   end,
-    {Query, CountQuery} = make_sql_query(User, LServer,
-					 Start, End, With, RSM),
-    % TODO from XEP-0313 v0.2: "To conserve resources, a server MAY place a
-    % reasonable limit on how many stanzas may be pushed to a client in one
-    % request. If a query returns a number of stanzas greater than this limit
-    % and the client did not specify a limit using RSM then the server should
-    % return a policy-violation error to the client." We currently don't do this
-    % for v0.2 requests, but we do limit #rsm_in.max for v0.3 and newer.
-    case {ejabberd_odbc:sql_query(Host, Query),
-	  ejabberd_odbc:sql_query(Host, CountQuery)} of
-	{{selected, _, Res}, {selected, _, [[Count]]}} ->
-	    {Max, Direction} = case RSM of
-				   #rsm_in{max = M, direction = D} -> {M, D};
-				   _ -> {undefined, undefined}
-			       end,
-	    {Res1, IsComplete} =
-		if Max >= 0 andalso Max /= undefined andalso length(Res) > Max ->
-			if Direction == before ->
-				{lists:nthtail(1, Res), false};
-			   true ->
-				{lists:sublist(Res, Max), false}
-			end;
-		   true ->
-			{Res, true}
-		end,
-	    {lists:flatmap(
-	       fun([TS, XML, PeerBin, Kind, Nick]) ->
-		       try
-			   #xmlel{} = El = fxml_stream:parse_element(XML),
-			   Now = usec_to_now(jlib:binary_to_integer(TS)),
-			   PeerJid = jid:tolower(jid:from_string(PeerBin)),
-			   T = case Kind of
-				   <<"">> -> chat;
-				   null -> chat;
-				   _ -> jlib:binary_to_atom(Kind)
-			       end,
-			   [{TS, jlib:binary_to_integer(TS),
-			     msg_to_el(#archive_msg{timestamp = Now,
-						    packet = El,
-						    type = T,
-						    nick = Nick,
-						    peer = PeerJid},
-				       MsgType, JidRequestor, JidArchive)}]
-		       catch _:Err ->
-			       ?ERROR_MSG("failed to parse data from SQL: ~p. "
-					  "The data was: "
-					  "timestamp = ~s, xml = ~s, "
-					  "peer = ~s, kind = ~s, nick = ~s",
-					  [Err, TS, XML, PeerBin, Kind, Nick]),
-			       []
-		       end
-	       end, Res1), IsComplete, jlib:binary_to_integer(Count)};
-	_ ->
-	    {[], false, 0}
-    end.
+select(LServer, From, From, Start, End, With, RSM, MsgType) ->
+    Mod = gen_mod:db_mod(LServer, ?MODULE),
+    Mod:select(LServer, From, From, Start, End, With, RSM, MsgType).
 
 msg_to_el(#archive_msg{timestamp = TS, packet = Pkt1, nick = Nick, peer = Peer},
 	  MsgType, JidRequestor, #jid{lserver = LServer} = JidArchive) ->
@@ -1160,7 +930,6 @@ send(From, To, Msgs, RSM, Count, IsComplete, #iq{sub_el = SubEl} = IQ) ->
 	    ignore
     end.
 
-
 make_rsm_out([], _, Count, Attrs, NS) ->
     Tag = if NS == ?NS_MAM_TMP -> <<"query">>;
 	     true -> <<"fin">>
@@ -1177,32 +946,6 @@ make_rsm_out([{FirstID, _, _}|_] = Msgs, _, Count, Attrs, NS) ->
 			 #rsm_out{first = FirstID, count = Count,
 				  last = LastID})}].
 
-filter_by_rsm(Msgs, none) ->
-    {Msgs, true};
-filter_by_rsm(_Msgs, #rsm_in{max = Max}) when Max < 0 ->
-    {[], true};
-filter_by_rsm(Msgs, #rsm_in{max = Max, direction = Direction, id = ID}) ->
-    NewMsgs = case Direction of
-		  aft when ID /= <<"">> ->
-		      lists:filter(
-			fun(#archive_msg{id = I}) ->
-				?BIN_GREATER_THAN(I, ID)
-			end, Msgs);
-		  before when ID /= <<"">> ->
-		      lists:foldl(
-			fun(#archive_msg{id = I} = Msg, Acc)
-				when ?BIN_LESS_THAN(I, ID) ->
-				[Msg|Acc];
-			   (_, Acc) ->
-				Acc
-			end, [], Msgs);
-		  before when ID == <<"">> ->
-		      lists:reverse(Msgs);
-		  _ ->
-		      Msgs
-	      end,
-    filter_by_max(NewMsgs, Max).
-
 filter_by_max(Msgs, undefined) ->
     {Msgs, true};
 filter_by_max(Msgs, Len) when is_integer(Len), Len >= 0 ->
@@ -1231,126 +974,6 @@ match_rsm(Now, #rsm_in{id = ID, direction = before}) when ID /= <<"">> ->
 match_rsm(_Now, _) ->
     true.
 
-make_matchspec(LUser, LServer, Start, End, {_, _, <<>>} = With) ->
-    ets:fun2ms(
-      fun(#archive_msg{timestamp = TS,
-		       us = US,
-		       bare_peer = BPeer} = Msg)
-	    when Start =< TS, End >= TS,
-		 US == {LUser, LServer},
-		 BPeer == With ->
-	      Msg
-      end);
-make_matchspec(LUser, LServer, Start, End, {_, _, _} = With) ->
-    ets:fun2ms(
-      fun(#archive_msg{timestamp = TS,
-		       us = US,
-		       peer = Peer} = Msg)
-	    when Start =< TS, End >= TS,
-		 US == {LUser, LServer},
-		 Peer == With ->
-	      Msg
-      end);
-make_matchspec(LUser, LServer, Start, End, none) ->
-    ets:fun2ms(
-      fun(#archive_msg{timestamp = TS,
-		       us = US,
-		       peer = Peer} = Msg)
-	    when Start =< TS, End >= TS,
-		 US == {LUser, LServer} ->
-	      Msg
-      end).
-
-make_sql_query(User, LServer, Start, End, With, RSM) ->
-    {Max, Direction, ID} = case RSM of
-	#rsm_in{} ->
-	    {RSM#rsm_in.max,
-		RSM#rsm_in.direction,
-		RSM#rsm_in.id};
-	none ->
-	    {none, none, <<>>}
-    end,
-    ODBCType = ejabberd_config:get_option(
-		 {odbc_type, LServer},
-		 ejabberd_odbc:opt_type(odbc_type)),
-    LimitClause = if is_integer(Max), Max >= 0, ODBCType /= mssql ->
-			  [<<" limit ">>, jlib:integer_to_binary(Max+1)];
-		     true ->
-			  []
-		  end,
-    TopClause = if is_integer(Max), Max >= 0, ODBCType == mssql ->
-			  [<<" TOP ">>, jlib:integer_to_binary(Max+1)];
-		     true ->
-			  []
-		  end,
-    WithClause = case With of
-		     {text, <<>>} ->
-			 [];
-		     {text, Txt} ->
-			 [<<" and match (txt) against ('">>,
-			  ejabberd_odbc:escape(Txt), <<"')">>];
-		     {_, _, <<>>} ->
-			 [<<" and bare_peer='">>,
-			  ejabberd_odbc:escape(jid:to_string(With)),
-			  <<"'">>];
-		     {_, _, _} ->
-			 [<<" and peer='">>,
-			  ejabberd_odbc:escape(jid:to_string(With)),
-			  <<"'">>];
-		     none ->
-			 []
-		 end,
-    PageClause = case catch jlib:binary_to_integer(ID) of
-		     I when is_integer(I), I >= 0 ->
-			 case Direction of
-			     before ->
-				 [<<" AND timestamp < ">>, ID];
-			     aft ->
-				 [<<" AND timestamp > ">>, ID];
-			     _ ->
-				 []
-			 end;
-		     _ ->
-			 []
-		 end,
-    StartClause = case Start of
-		      {_, _, _} ->
-			  [<<" and timestamp >= ">>,
-			   jlib:integer_to_binary(now_to_usec(Start))];
-		      _ ->
-			  []
-		  end,
-    EndClause = case End of
-		    {_, _, _} ->
-			[<<" and timestamp <= ">>,
-			 jlib:integer_to_binary(now_to_usec(End))];
-		    _ ->
-			[]
-		end,
-    SUser = ejabberd_odbc:escape(User),
-
-    Query = [<<"SELECT ">>, TopClause, <<" timestamp, xml, peer, kind, nick"
-	      " FROM archive WHERE username='">>,
-	     SUser, <<"'">>, WithClause, StartClause, EndClause,
-	     PageClause],
-
-    QueryPage =
-	case Direction of
-	    before ->
-		% ID can be empty because of
-		% XEP-0059: Result Set Management
-		% 2.5 Requesting the Last Page in a Result Set
-		[<<"SELECT timestamp, xml, peer, kind, nick FROM (">>, Query,
-		 <<" ORDER BY timestamp DESC ">>,
-		 LimitClause, <<") AS t ORDER BY timestamp ASC;">>];
-	    _ ->
-		[Query, <<" ORDER BY timestamp ASC ">>,
-		 LimitClause, <<";">>]
-	end,
-    {QueryPage,
-     [<<"SELECT COUNT(*) FROM archive WHERE username='">>,
-      SUser, <<"'">>, WithClause, StartClause, EndClause, <<";">>]}.
-
 now_to_usec({MSec, Sec, USec}) ->
     (MSec*1000000 + Sec)*1000000 + USec.
 
@@ -1376,28 +999,6 @@ get_jids(Els) ->
 	      []
       end, Els).
 
-update(LServer, Table, Fields, Vals, Where) ->
-    UPairs = lists:zipwith(fun (A, B) ->
-				   <<A/binary, "='", B/binary, "'">>
-			   end,
-			   Fields, Vals),
-    case ejabberd_odbc:sql_query(LServer,
-				 [<<"update ">>, Table, <<" set ">>,
-				  join(UPairs, <<", ">>), <<" where ">>, Where,
-				  <<";">>])
-	of
-	{updated, 1} -> {updated, 1};
-	_ ->
-	    ejabberd_odbc:sql_query(LServer,
-				    [<<"insert into ">>, Table, <<"(">>,
-				     join(Fields, <<", ">>), <<") values ('">>,
-				     join(Vals, <<"', '">>), <<"');">>])
-    end.
-
-%% Almost a copy of string:join/2.
-join([], _Sep) -> [];
-join([H | T], Sep) -> [H, [[Sep, X] || X <- T]].
-
 get_commands_spec() ->
     [#ejabberd_commands{name = delete_old_mam_messages, tags = [purge],
 			desc = "Delete MAM messages older than DAYS",
@@ -1416,7 +1017,11 @@ mod_opt_type(cache_life_time) ->
     fun (I) when is_integer(I), I > 0 -> I end;
 mod_opt_type(cache_size) ->
     fun (I) when is_integer(I), I > 0 -> I end;
-mod_opt_type(db_type) -> fun gen_mod:v_db/1;
+mod_opt_type(db_type) ->
+    fun(odbc) -> odbc;
+       (internal) -> mnesia;
+       (mnesia) -> mnesia
+    end;
 mod_opt_type(default) ->
     fun (always) -> always;
 	(never) -> never;
diff --git a/src/mod_mam_mnesia.erl b/src/mod_mam_mnesia.erl
new file mode 100644
index 000000000..007ef5eba
--- /dev/null
+++ b/src/mod_mam_mnesia.erl
@@ -0,0 +1,178 @@
+%%%-------------------------------------------------------------------
+%%% @author Evgeny Khramtsov <ekhramtsov@process-one.net>
+%%% @copyright (C) 2016, Evgeny Khramtsov
+%%% @doc
+%%%
+%%% @end
+%%% Created : 15 Apr 2016 by Evgeny Khramtsov <ekhramtsov@process-one.net>
+%%%-------------------------------------------------------------------
+-module(mod_mam_mnesia).
+
+-behaviour(mod_mam).
+
+%% API
+-export([init/2, remove_user/2, remove_room/3, delete_old_messages/3,
+	 extended_fields/0, store/7, write_prefs/4, get_prefs/2, select/8]).
+
+-include_lib("stdlib/include/ms_transform.hrl").
+-include("jlib.hrl").
+-include("mod_mam.hrl").
+
+-define(BIN_GREATER_THAN(A, B),
+	((A > B andalso byte_size(A) == byte_size(B))
+	 orelse byte_size(A) > byte_size(B))).
+-define(BIN_LESS_THAN(A, B),
+	((A < B andalso byte_size(A) == byte_size(B))
+	 orelse byte_size(A) < byte_size(B))).
+
+%%%===================================================================
+%%% API
+%%%===================================================================
+init(_Host, _Opts) ->
+    mnesia:create_table(archive_msg,
+			[{disc_only_copies, [node()]},
+			 {type, bag},
+			 {attributes, record_info(fields, archive_msg)}]),
+    mnesia:create_table(archive_prefs,
+			[{disc_only_copies, [node()]},
+			 {attributes, record_info(fields, archive_prefs)}]).
+
+remove_user(LUser, LServer) ->
+    US = {LUser, LServer},
+    F = fun () ->
+		mnesia:delete({archive_msg, US}),
+		mnesia:delete({archive_prefs, US})
+	end,
+    mnesia:transaction(F).
+
+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).
+
+extended_fields() ->
+    [].
+
+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 ->
+	    {ok, ID};
+	Err ->
+	    Err
+    end.
+
+write_prefs(_LUser, _LServer, Prefs, _ServerHost) ->
+    mnesia:dirty_write(Prefs).
+
+get_prefs(LUser, LServer) ->
+    case mnesia:dirty_read(archive_prefs, {LUser, LServer}) of
+	[Prefs] ->
+	    {ok, Prefs};
+	_ ->
+	    error
+    end.
+
+select(_LServer, JidRequestor,
+       #jid{luser = LUser, lserver = LServer} = JidArchive,
+       Start, End, With, RSM, MsgType) ->
+    MS = make_matchspec(LUser, LServer, Start, End, With),
+    Msgs = mnesia:dirty_select(archive_msg, MS),
+    SortedMsgs = lists:keysort(#archive_msg.timestamp, Msgs),
+    {FilteredMsgs, IsComplete} = filter_by_rsm(SortedMsgs, RSM),
+    Count = length(Msgs),
+    {lists:map(
+       fun(Msg) ->
+	       {Msg#archive_msg.id,
+		jlib:binary_to_integer(Msg#archive_msg.id),
+		mod_mam:msg_to_el(Msg, MsgType, JidRequestor, JidArchive)}
+       end, FilteredMsgs), IsComplete, Count}.
+
+%%%===================================================================
+%%% Internal functions
+%%%===================================================================
+now_to_usec({MSec, Sec, USec}) ->
+    (MSec*1000000 + Sec)*1000000 + USec.
+
+make_matchspec(LUser, LServer, Start, End, {_, _, <<>>} = With) ->
+    ets:fun2ms(
+      fun(#archive_msg{timestamp = TS,
+		       us = US,
+		       bare_peer = BPeer} = Msg)
+	    when Start =< TS, End >= TS,
+		 US == {LUser, LServer},
+		 BPeer == With ->
+	      Msg
+      end);
+make_matchspec(LUser, LServer, Start, End, {_, _, _} = With) ->
+    ets:fun2ms(
+      fun(#archive_msg{timestamp = TS,
+		       us = US,
+		       peer = Peer} = Msg)
+	    when Start =< TS, End >= TS,
+		 US == {LUser, LServer},
+		 Peer == With ->
+	      Msg
+      end);
+make_matchspec(LUser, LServer, Start, End, none) ->
+    ets:fun2ms(
+      fun(#archive_msg{timestamp = TS,
+		       us = US,
+		       peer = Peer} = Msg)
+	    when Start =< TS, End >= TS,
+		 US == {LUser, LServer} ->
+	      Msg
+      end).
+
+filter_by_rsm(Msgs, none) ->
+    {Msgs, true};
+filter_by_rsm(_Msgs, #rsm_in{max = Max}) when Max < 0 ->
+    {[], true};
+filter_by_rsm(Msgs, #rsm_in{max = Max, direction = Direction, id = ID}) ->
+    NewMsgs = case Direction of
+		  aft when ID /= <<"">> ->
+		      lists:filter(
+			fun(#archive_msg{id = I}) ->
+				?BIN_GREATER_THAN(I, ID)
+			end, Msgs);
+		  before when ID /= <<"">> ->
+		      lists:foldl(
+			fun(#archive_msg{id = I} = Msg, Acc)
+				when ?BIN_LESS_THAN(I, ID) ->
+				[Msg|Acc];
+			   (_, Acc) ->
+				Acc
+			end, [], Msgs);
+		  before when ID == <<"">> ->
+		      lists:reverse(Msgs);
+		  _ ->
+		      Msgs
+	      end,
+    filter_by_max(NewMsgs, Max).
+
+filter_by_max(Msgs, undefined) ->
+    {Msgs, true};
+filter_by_max(Msgs, Len) when is_integer(Len), Len >= 0 ->
+    {lists:sublist(Msgs, Len), length(Msgs) =< Len};
+filter_by_max(_Msgs, _Junk) ->
+    {[], true}.
diff --git a/src/mod_mam_sql.erl b/src/mod_mam_sql.erl
new file mode 100644
index 000000000..1f24de317
--- /dev/null
+++ b/src/mod_mam_sql.erl
@@ -0,0 +1,309 @@
+%%%-------------------------------------------------------------------
+%%% @author Evgeny Khramtsov <ekhramtsov@process-one.net>
+%%% @copyright (C) 2016, Evgeny Khramtsov
+%%% @doc
+%%%
+%%% @end
+%%% Created : 15 Apr 2016 by Evgeny Khramtsov <ekhramtsov@process-one.net>
+%%%-------------------------------------------------------------------
+-module(mod_mam_sql).
+
+-behaviour(mod_mam).
+
+%% API
+-export([init/2, remove_user/2, remove_room/3, delete_old_messages/3,
+	 extended_fields/0, store/7, write_prefs/4, get_prefs/2, select/8]).
+
+-include_lib("stdlib/include/ms_transform.hrl").
+-include("jlib.hrl").
+-include("mod_mam.hrl").
+-include("logger.hrl").
+
+%%%===================================================================
+%%% API
+%%%===================================================================
+init(_Host, _Opts) ->
+    ok.
+
+remove_user(LUser, LServer) ->
+    SUser = ejabberd_odbc:escape(LUser),
+    ejabberd_odbc:sql_query(
+      LServer,
+      [<<"delete from archive where username='">>, SUser, <<"';">>]),
+    ejabberd_odbc:sql_query(
+      LServer,
+      [<<"delete from archive_prefs where username='">>, SUser, <<"';">>]).
+
+remove_room(LServer, LName, LHost) ->
+    LUser = jid:to_string({LName, LHost, <<>>}),
+    remove_user(LUser, LServer).
+
+delete_old_messages(ServerHost, TimeStamp, Type) ->
+    TypeClause = if Type == all -> <<"">>;
+		    true -> [<<" and kind='">>, jlib:atom_to_binary(Type), <<"'">>]
+		 end,
+    TS = integer_to_binary(now_to_usec(TimeStamp)),
+    ejabberd_odbc:sql_query(
+      ServerHost, [<<"delete from archive where timestamp<">>,
+		   TS, TypeClause, <<";">>]),
+    ok.
+
+extended_fields() ->
+    [#xmlel{name = <<"field">>,
+	    attrs = [{<<"type">>, <<"text-single">>},
+		     {<<"var">>, <<"withtext">>}]}].
+
+store(Pkt, LServer, {LUser, LHost}, Type, Peer, Nick, _Dir) ->
+    TSinteger = p1_time_compat:system_time(micro_seconds),
+    ID = TS = jlib:integer_to_binary(TSinteger),
+    SUser = case Type of
+		chat -> LUser;
+		groupchat -> jid:to_string({LUser, LHost, <<>>})
+	    end,
+    BarePeer = jid:to_string(
+		 jid:tolower(
+		   jid:remove_resource(Peer))),
+    LPeer = jid:to_string(
+	      jid:tolower(Peer)),
+    XML = fxml:element_to_binary(Pkt),
+    Body = fxml:get_subtag_cdata(Pkt, <<"body">>),
+    case ejabberd_odbc:sql_query(
+	    LServer,
+	    [<<"insert into archive (username, timestamp, "
+		    "peer, bare_peer, xml, txt, kind, nick) values (">>,
+		<<"'">>, ejabberd_odbc:escape(SUser), <<"', ">>,
+		<<"'">>, TS, <<"', ">>,
+		<<"'">>, ejabberd_odbc:escape(LPeer), <<"', ">>,
+		<<"'">>, ejabberd_odbc:escape(BarePeer), <<"', ">>,
+		<<"'">>, ejabberd_odbc:escape(XML), <<"', ">>,
+		<<"'">>, ejabberd_odbc:escape(Body), <<"', ">>,
+		<<"'">>, jlib:atom_to_binary(Type), <<"', ">>,
+		<<"'">>, ejabberd_odbc:escape(Nick), <<"');">>]) of
+	{updated, _} ->
+	    {ok, ID};
+	Err ->
+	    Err
+    end.
+
+write_prefs(LUser, _LServer, #archive_prefs{default = Default,
+					   never = Never,
+					   always = Always},
+	    ServerHost) ->
+    SUser = ejabberd_odbc:escape(LUser),
+    SDefault = erlang:atom_to_binary(Default, utf8),
+    SAlways = ejabberd_odbc:encode_term(Always),
+    SNever = ejabberd_odbc:encode_term(Never),
+    case update(ServerHost, <<"archive_prefs">>,
+		[<<"username">>, <<"def">>, <<"always">>, <<"never">>],
+		[SUser, SDefault, SAlways, SNever],
+		[<<"username='">>, SUser, <<"'">>]) of
+	{updated, _} ->
+	    ok;
+	Err ->
+	    Err
+    end.
+
+get_prefs(LUser, LServer) ->
+    case ejabberd_odbc:sql_query(
+	   LServer,
+	   [<<"select def, always, never from archive_prefs ">>,
+	    <<"where username='">>,
+	    ejabberd_odbc:escape(LUser), <<"';">>]) of
+	{selected, _, [[SDefault, SAlways, SNever]]} ->
+	    Default = erlang:binary_to_existing_atom(SDefault, utf8),
+	    Always = ejabberd_odbc:decode_term(SAlways),
+	    Never = ejabberd_odbc:decode_term(SNever),
+	    {ok, #archive_prefs{us = {LUser, LServer},
+		    default = Default,
+		    always = Always,
+		    never = Never}};
+	_ ->
+	    error
+    end.
+
+select(LServer, JidRequestor, #jid{luser = LUser} = JidArchive,
+       Start, End, With, RSM, MsgType) ->
+    User = case MsgType of
+	       chat -> LUser;
+	       {groupchat, _Role, _MUCState} -> jid:to_string(JidArchive)
+	   end,
+    {Query, CountQuery} = make_sql_query(User, LServer,
+					 Start, End, With, RSM),
+    % TODO from XEP-0313 v0.2: "To conserve resources, a server MAY place a
+    % reasonable limit on how many stanzas may be pushed to a client in one
+    % request. If a query returns a number of stanzas greater than this limit
+    % and the client did not specify a limit using RSM then the server should
+    % return a policy-violation error to the client." We currently don't do this
+    % for v0.2 requests, but we do limit #rsm_in.max for v0.3 and newer.
+    case {ejabberd_odbc:sql_query(LServer, Query),
+	  ejabberd_odbc:sql_query(LServer, CountQuery)} of
+	{{selected, _, Res}, {selected, _, [[Count]]}} ->
+	    {Max, Direction} = case RSM of
+				   #rsm_in{max = M, direction = D} -> {M, D};
+				   _ -> {undefined, undefined}
+			       end,
+	    {Res1, IsComplete} =
+		if Max >= 0 andalso Max /= undefined andalso length(Res) > Max ->
+			if Direction == before ->
+				{lists:nthtail(1, Res), false};
+			   true ->
+				{lists:sublist(Res, Max), false}
+			end;
+		   true ->
+			{Res, true}
+		end,
+	    {lists:flatmap(
+	       fun([TS, XML, PeerBin, Kind, Nick]) ->
+		       try
+			   #xmlel{} = El = fxml_stream:parse_element(XML),
+			   Now = usec_to_now(jlib:binary_to_integer(TS)),
+			   PeerJid = jid:tolower(jid:from_string(PeerBin)),
+			   T = case Kind of
+				   <<"">> -> chat;
+				   null -> chat;
+				   _ -> jlib:binary_to_atom(Kind)
+			       end,
+			   [{TS, jlib:binary_to_integer(TS),
+			     mod_mam:msg_to_el(#archive_msg{timestamp = Now,
+							    packet = El,
+							    type = T,
+							    nick = Nick,
+							    peer = PeerJid},
+					       MsgType, JidRequestor, JidArchive)}]
+		       catch _:Err ->
+			       ?ERROR_MSG("failed to parse data from SQL: ~p. "
+					  "The data was: "
+					  "timestamp = ~s, xml = ~s, "
+					  "peer = ~s, kind = ~s, nick = ~s",
+					  [Err, TS, XML, PeerBin, Kind, Nick]),
+			       []
+		       end
+	       end, Res1), IsComplete, jlib:binary_to_integer(Count)};
+	_ ->
+	    {[], false, 0}
+    end.
+
+%%%===================================================================
+%%% Internal functions
+%%%===================================================================
+now_to_usec({MSec, Sec, USec}) ->
+    (MSec*1000000 + Sec)*1000000 + USec.
+
+usec_to_now(Int) ->
+    Secs = Int div 1000000,
+    USec = Int rem 1000000,
+    MSec = Secs div 1000000,
+    Sec = Secs rem 1000000,
+    {MSec, Sec, USec}.
+
+make_sql_query(User, LServer, Start, End, With, RSM) ->
+    {Max, Direction, ID} = case RSM of
+	#rsm_in{} ->
+	    {RSM#rsm_in.max,
+		RSM#rsm_in.direction,
+		RSM#rsm_in.id};
+	none ->
+	    {none, none, <<>>}
+    end,
+    ODBCType = ejabberd_config:get_option(
+		 {odbc_type, LServer},
+		 ejabberd_odbc:opt_type(odbc_type)),
+    LimitClause = if is_integer(Max), Max >= 0, ODBCType /= mssql ->
+			  [<<" limit ">>, jlib:integer_to_binary(Max+1)];
+		     true ->
+			  []
+		  end,
+    TopClause = if is_integer(Max), Max >= 0, ODBCType == mssql ->
+			  [<<" TOP ">>, jlib:integer_to_binary(Max+1)];
+		     true ->
+			  []
+		  end,
+    WithClause = case With of
+		     {text, <<>>} ->
+			 [];
+		     {text, Txt} ->
+			 [<<" and match (txt) against ('">>,
+			  ejabberd_odbc:escape(Txt), <<"')">>];
+		     {_, _, <<>>} ->
+			 [<<" and bare_peer='">>,
+			  ejabberd_odbc:escape(jid:to_string(With)),
+			  <<"'">>];
+		     {_, _, _} ->
+			 [<<" and peer='">>,
+			  ejabberd_odbc:escape(jid:to_string(With)),
+			  <<"'">>];
+		     none ->
+			 []
+		 end,
+    PageClause = case catch jlib:binary_to_integer(ID) of
+		     I when is_integer(I), I >= 0 ->
+			 case Direction of
+			     before ->
+				 [<<" AND timestamp < ">>, ID];
+			     aft ->
+				 [<<" AND timestamp > ">>, ID];
+			     _ ->
+				 []
+			 end;
+		     _ ->
+			 []
+		 end,
+    StartClause = case Start of
+		      {_, _, _} ->
+			  [<<" and timestamp >= ">>,
+			   jlib:integer_to_binary(now_to_usec(Start))];
+		      _ ->
+			  []
+		  end,
+    EndClause = case End of
+		    {_, _, _} ->
+			[<<" and timestamp <= ">>,
+			 jlib:integer_to_binary(now_to_usec(End))];
+		    _ ->
+			[]
+		end,
+    SUser = ejabberd_odbc:escape(User),
+
+    Query = [<<"SELECT ">>, TopClause, <<" timestamp, xml, peer, kind, nick"
+	      " FROM archive WHERE username='">>,
+	     SUser, <<"'">>, WithClause, StartClause, EndClause,
+	     PageClause],
+
+    QueryPage =
+	case Direction of
+	    before ->
+		% ID can be empty because of
+		% XEP-0059: Result Set Management
+		% 2.5 Requesting the Last Page in a Result Set
+		[<<"SELECT timestamp, xml, peer, kind, nick FROM (">>, Query,
+		 <<" ORDER BY timestamp DESC ">>,
+		 LimitClause, <<") AS t ORDER BY timestamp ASC;">>];
+	    _ ->
+		[Query, <<" ORDER BY timestamp ASC ">>,
+		 LimitClause, <<";">>]
+	end,
+    {QueryPage,
+     [<<"SELECT COUNT(*) FROM archive WHERE username='">>,
+      SUser, <<"'">>, WithClause, StartClause, EndClause, <<";">>]}.
+
+update(LServer, Table, Fields, Vals, Where) ->
+    UPairs = lists:zipwith(fun (A, B) ->
+				   <<A/binary, "='", B/binary, "'">>
+			   end,
+			   Fields, Vals),
+    case ejabberd_odbc:sql_query(LServer,
+				 [<<"update ">>, Table, <<" set ">>,
+				  join(UPairs, <<", ">>), <<" where ">>, Where,
+				  <<";">>])
+	of
+	{updated, 1} -> {updated, 1};
+	_ ->
+	    ejabberd_odbc:sql_query(LServer,
+				    [<<"insert into ">>, Table, <<"(">>,
+				     join(Fields, <<", ">>), <<") values ('">>,
+				     join(Vals, <<"', '">>), <<"');">>])
+    end.
+
+%% Almost a copy of string:join/2.
+join([], _Sep) -> [];
+join([H | T], Sep) -> [H, [[Sep, X] || X <- T]].
diff --git a/src/mod_muc.erl b/src/mod_muc.erl
index 95631e25c..6aa186318 100644
--- a/src/mod_muc.erl
+++ b/src/mod_muc.erl
@@ -154,15 +154,7 @@ forget_room(ServerHost, Host, Name) ->
 remove_room_mam(LServer, Host, Name) ->
     case gen_mod:is_loaded(LServer, mod_mam) of
 	true ->
-	    U = jid:nodeprep(Name),
-	    S = jid:nameprep(Host),
-	    DBType = gen_mod:db_type(LServer, mod_mam),
-	    if DBType == odbc ->
-		    mod_mam:remove_user(jid:to_string({U, S, <<>>}),
-					LServer, DBType);
-	       true ->
-		    mod_mam:remove_user(U, S, DBType)
-	    end;
+	    mod_mam:remove_room(LServer, Name, Host);
 	false ->
 	    ok
     end.