1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
|
%% ``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.
|
