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+%% ``The contents of this file are subject to the Erlang Public License,
+%% Version 1.1, (the "License"); you may not use this file except in
+%% compliance with the License. You should have received a copy of the
+%% Erlang Public License along with this software. If not, it can be
+%% retrieved via the world wide web at http://www.erlang.org/.
+%%
+%% Software distributed under the License is distributed on an "AS IS"
+%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+%% the License for the specific language governing rights and limitations
+%% under the License.
+%%
+%% The Initial Developer of the Original Code is Ericsson Utvecklings AB.
+%% Portions created by Ericsson are Copyright 1999, Ericsson Utvecklings
+%% AB. All Rights Reserved.''
+%%
+%% $Id$
+%%
+-module(bup).
+-export([
+ change_node_name/5,
+ view/2,
+ test/0,
+ test/1
+ ]).
+
+-export([
+ count/1,
+ display/1
+ ]).
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% Management of backups, a few demos
+
+%0
+change_node_name(Mod, From, To, Source, Target) ->
+ Switch =
+ fun(Node) when Node == From -> To;
+ (Node) when Node == To -> throw({error, already_exists});
+ (Node) -> Node
+ end,
+ Convert =
+ fun({schema, db_nodes, Nodes}, Acc) ->
+ {[{schema, db_nodes, lists:map(Switch,Nodes)}], Acc};
+ ({schema, version, Version}, Acc) ->
+ {[{schema, version, Version}], Acc};
+ ({schema, cookie, Cookie}, Acc) ->
+ {[{schema, cookie, Cookie}], Acc};
+ ({schema, Tab, CreateList}, Acc) ->
+ Keys = [ram_copies, disc_copies, disc_only_copies],
+ OptSwitch =
+ fun({Key, Val}) ->
+ case lists:member(Key, Keys) of
+ true -> {Key, lists:map(Switch, Val)};
+ false-> {Key, Val}
+ end
+ end,
+ {[{schema, Tab, lists:map(OptSwitch, CreateList)}], Acc};
+ (Other, Acc) ->
+ {[Other], Acc}
+ end,
+ mnesia:traverse_backup(Source, Mod, Target, Mod, Convert, switched).
+
+view(Source, Mod) ->
+ View = fun(Item, Acc) ->
+ io:format("~p.~n",[Item]),
+ {[Item], Acc + 1}
+ end,
+ mnesia:traverse_backup(Source, Mod, dummy, read_only, View, 0).
+%0
+
+-record(bup_rec, {key, val}).
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% Test change of node name
+%%
+%% Assume db_nodes to be current node and on all other nodes but one
+%% Create new schema, start Mnesia on all db_nodes
+%% Create a table of disc_copies type which is replicated to all db_nodes
+%% Perform a backup and change current node to unused node in backup
+%% Start Mnesia on all nodes according to the new set of db_nodes
+test() ->
+ test(nodes()).
+
+test(Nodes)->
+ AllNodes = (Nodes -- [node()]) ++ [node()],
+ case length(AllNodes) of
+ Length when Length > 1 ->
+ OldBup = "old.BUP",
+ NewBup = "new.BUP",
+ Res = (catch test2(AllNodes, OldBup, NewBup)),
+ case Res of
+ {'EXIT', Reason} ->
+ file:delete(OldBup),
+ file:delete(NewBup),
+ {error, Reason};
+ ok ->
+ ok = count(NewBup),
+ file:delete(OldBup),
+ file:delete(NewBup),
+ ok
+ end;
+ _ ->
+ {error,{"Must run on at least one other node",AllNodes}}
+ end.
+
+test2(AllNodes, OldBup, NewBup) ->
+ ThisNode = node(),
+ OtherNode = hd(AllNodes -- [ThisNode]),
+ OldNodes = AllNodes -- [OtherNode],
+ NewNodes = AllNodes -- [ThisNode],
+ Mod = mnesia_backup, % Assume local files
+ file:delete(OldBup),
+ file:delete(NewBup),
+
+ %% Create old backup
+ rpc:multicall(AllNodes, mnesia, lkill, []),
+ ok = mnesia:delete_schema(AllNodes),
+ ok = mnesia:create_schema(OldNodes),
+ rpc:multicall(OldNodes, mnesia, start, []),
+ rpc:multicall(OldNodes, mnesia, wait_for_tables, [[schema], infinity]),
+
+ CreateList = [{disc_copies, OldNodes},
+ {attributes, record_info(fields, bup_rec)}],
+ {atomic, ok} = mnesia:create_table(bup_rec, CreateList),
+ rpc:multicall(OldNodes, mnesia, wait_for_tables, [[bup_rec], infinity]),
+ OldRecs = [#bup_rec{key = I, val = I * I} || I <- lists:seq(1, 10)],
+ lists:foreach(fun(R) -> ok = mnesia:dirty_write(R) end,OldRecs),
+ ok = mnesia:backup(OldBup, Mod),
+ ok = mnesia:dirty_write(#bup_rec{key = 4711, val = 4711}),
+ rpc:multicall(OldNodes, mnesia, stop, []),
+ {ok,_} = view(OldBup, Mod),
+
+ %% Change node name
+ {ok,_} = change_node_name(Mod, ThisNode, OtherNode, OldBup, NewBup),
+ ok = rpc:call(OtherNode, mnesia, install_fallback, [NewBup, Mod]),
+ {_NewStartRes,[]} = rpc:multicall(NewNodes, mnesia, start, []),
+ rpc:call(OtherNode, mnesia, wait_for_tables, [[bup_rec], infinity]),
+ Wild = rpc:call(OtherNode, mnesia, table_info, [bup_rec, wild_pattern]),
+ NewRecs = rpc:call(OtherNode, mnesia, dirty_match_object, [Wild]),
+ rpc:multicall(NewNodes, mnesia, stop, []),
+ {ok,_} = view(NewBup, Mod),
+
+ %% Sanity test
+ case {lists:sort(OldRecs), lists:sort(NewRecs)} of
+ {Same, Same} -> ok
+ end.
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+-record(state, {counter_tab, size_tab, acc_size = 0, n_records = 0}).
+
+
+%% Iterates over a backup file and shows some statistics
+%% The identity of ets table containing the counters is not removed
+count(BupFile) ->
+ CounterTab = ets:new(?MODULE, [set, public]),
+ SizeTab = ets:new(?MODULE, [set, public]),
+ Mod = mnesia:system_info(backup_module),
+ State = #state{counter_tab = CounterTab, size_tab = SizeTab},
+ case mnesia:traverse_backup(BupFile, Mod, dummy, read_only, fun incr/2, State) of
+ {ok, State2} ->
+ Res = display(State2),
+ ets:delete(CounterTab),
+ ets:delete(SizeTab),
+ Res;
+ {error, Reason} ->
+ ets:delete(CounterTab),
+ ets:delete(SizeTab),
+ {error, Reason}
+ end.
+
+incr(Rec, State) ->
+ Tab = element(1, Rec),
+ Key = element(2, Rec),
+ Oid = {Tab, Key},
+ incr_counter(State#state.counter_tab, Oid),
+ Size = size(term_to_binary(Rec)),
+ max_size(State#state.size_tab, Tab, Key, Size),
+ AccSize = State#state.acc_size,
+ N = State#state.n_records,
+ State2 = State#state{acc_size = AccSize + Size, n_records = N + 1},
+ {[Rec], State2}.
+
+incr_counter(T, Counter) ->
+ case catch ets:update_counter(T, Counter, 1) of
+ {'EXIT', _} ->
+ ets:insert(T, {Counter, 1});
+ _ ->
+ ignore
+ end.
+
+max_size(T, Tab, Key, Size) ->
+ case catch ets:lookup_element(T, Tab, 2) of
+ {'EXIT', _} ->
+ ets:insert(T, {Tab, Size, Key});
+ OldSize when OldSize < Size ->
+ ets:insert(T, {Tab, Size, Key});
+ _ ->
+ ignore
+ end.
+
+%% Displays the statistics found in the ets table
+display(State) ->
+ CounterTab = State#state.counter_tab,
+ Tabs = [T || {{_, T}, _} <- match_tab(CounterTab, schema)],
+ io:format("~w tables with totally: ~w records, ~w keys, ~w bytes~n",
+ [length(Tabs),
+ State#state.n_records,
+ ets:info(CounterTab, size),
+ State#state.acc_size]),
+ display(State, lists:sort(Tabs)).
+
+display(State, [Tab | Tabs]) ->
+ Counters = match_tab(State#state.counter_tab, Tab),
+ io:format("~-10w records in table ~w~n", [length(Counters), Tab]),
+ Fun = fun({_Oid, Val}) when Val < 5 ->
+ ignore;
+ ({Oid, Val}) ->
+ io:format("~-10w *** records with key ~w~n", [Val, Oid])
+ end,
+ lists:foreach(Fun, Counters),
+ display_size(State#state.size_tab, Tab),
+ display(State, Tabs);
+display(_CounterTab, []) ->
+ ok.
+
+match_tab(T, Tab) ->
+ ets:match_object(T, {{Tab, '_'}, '_'}).
+
+display_size(T, Tab) ->
+ case catch ets:lookup(T, Tab) of
+ [] ->
+ ignore;
+ [{_, Size, Key}] when Size > 1000 ->
+ io:format("~-10w --- bytes occupied by largest record ~w~n",
+ [Size, {Tab, Key}]);
+ [{_, _, _}] ->
+ ignore
+ end.
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