aboutsummaryrefslogblamecommitdiffstats
path: root/lib/mnesia/src/mnesia_controller.erl
blob: 836510a80d7b7b6c0c4859d6b7d7874c580ee3b7 (plain) (tree)
1
2
3
4
5
6
7
8
9
10
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238

                   
  
                                                        
  




                                                                      
  



                                                                         
  





































                                                                   
                         



                                       

                                               













                                            
                                 






















                                  
                         

           

                                     
















































































































































































                                                                                  
                        
                                                                        
 

                                                                                   

                                                       
                                                                    
 














































































































































                                                                                   



                                           



                                                
                                                                          
















                                                                               
                                      






                                                    
                                             












                                                                    
                                                                     







                                                         


                   
                                          
                                               

                                                                  






                                                                     







                                                              




                                                           

                                                                         




                                                                      















































































































































































                                                                                            

                                                                     











































































































































































































































                                                                                        
                                      





























































                                                                             
                                                     


                                                                    

                                                              



























































                                                             

                                              
























                                                                                               






























































































































































































































































































































































































































































































































































































































                                                                                          

                               








                                                                    

                                                







                                                                           















                                                          






























































































































































                                                                                             













                                                                      






































































































































































































































































































































                                                                                             
%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 1996-2011. All Rights Reserved.
%%
%% 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 online 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.
%%
%% %CopyrightEnd%
%%

%%
%% The mnesia_init process loads tables from local disc or from
%% another nodes. It also coordinates updates of the info about
%% where we can read and write tables.
%%
%% Tables may need to be loaded initially at startup of the local
%% node or when other nodes announces that they already have loaded
%% tables that we also want.
%%
%% Initially we set the load request queue to those tables that we
%% safely can load locally, i.e. tables where we have the last
%% consistent replica and we have received mnesia_down from all
%% other nodes holding the table. Then we let the mnesia_init
%% process enter its normal working state.
%%
%% When we need to load a table we append a request to the load
%% request queue. All other requests are regarded as high priority
%% and are processed immediately (e.g. update table whereabouts).
%% We processes the load request queue as a "background" job..

-module(mnesia_controller).

-behaviour(gen_server).

%% Mnesia internal stuff
-export([
	 start/0,
	 i_have_tab/1,
	 info/0,
	 get_info/1,
	 get_workers/1,
	 force_load_table/1,
	 async_dump_log/1,
	 sync_dump_log/1,
	 connect_nodes/1,
         connect_nodes/2,
	 wait_for_schema_commit_lock/0,
	 release_schema_commit_lock/0,
	 create_table/1,
	 get_disc_copy/1,
	 get_remote_cstructs/0,  % new function
	 get_cstructs/0,         % old function
	 sync_and_block_table_whereabouts/4,
	 sync_del_table_copy_whereabouts/2,
	 block_table/1,
	 unblock_table/1,
	 block_controller/0,
	 unblock_controller/0,
	 unannounce_add_table_copy/2,
	 master_nodes_updated/2,
	 mnesia_down/1,
	 add_active_replica/2,
	 add_active_replica/3,
	 add_active_replica/4,
	 update/1,
	 change_table_access_mode/1,
	 change_table_majority/1,
	 del_active_replica/2,
	 wait_for_tables/2,
	 get_network_copy/2,
	 merge_schema/0,
	 start_remote_sender/4,
	 schedule_late_disc_load/2
	]).

%% gen_server callbacks
-export([init/1,
	 handle_call/3,
	 handle_cast/2,
	 handle_info/2,
	 terminate/2,
	 code_change/3]).

%% Module internal stuff
-export([call/1,
	 cast/1,
	 dump_and_reply/2,
	 load_and_reply/2,
	 send_and_reply/2,
	 wait_for_tables_init/2,
	 connect_nodes2/3
	]).

-compile({no_auto_import,[error/2]}).

-import(mnesia_lib, [set/2, add/2]).
-import(mnesia_lib, [fatal/2, error/2, verbose/2, dbg_out/2]).

-include("mnesia.hrl").

-define(SERVER_NAME, ?MODULE).  

-record(state, {supervisor,
		schema_is_merged = false,
		early_msgs = [],
		loader_pid = [],     %% Was Pid is now [{Pid,Work}|..] 
		loader_queue,        %% Was list is now gb_tree
		sender_pid = [],     %% Was a pid or undef is now [{Pid,Work}|..] 
		sender_queue =  [],
		late_loader_queue,   %% Was list is now gb_tree
		dumper_pid,          %% Dumper or schema commit pid
		dumper_queue = [],   %% Dumper or schema commit queue
		others = [],         %% Processes that needs the copier_done msg
		dump_log_timer_ref,
		is_stopping = false
	       }).
%% Backwards Comp. Sender_pid is now a list of senders..
get_senders(#state{sender_pid = Pids}) when is_list(Pids) -> Pids.    
%% Backwards Comp. loader_pid is now a list of loaders..
get_loaders(#state{loader_pid = Pids}) when is_list(Pids) -> Pids.    
max_loaders() ->
    case ?catch_val(no_table_loaders) of
	{'EXIT', _} -> 
	    mnesia_lib:set(no_table_loaders,1),
	    1;
	Val -> Val
    end.

-record(schema_commit_lock, {owner}).
-record(block_controller, {owner}).

-record(dump_log, {initiated_by,
		   opt_reply_to
		  }).

-record(net_load, {table,
		   reason,
		   opt_reply_to,
		   cstruct = unknown
		  }).

-record(send_table, {table,
		     receiver_pid,
		     remote_storage
		    }).

-record(disc_load, {table, 
		    reason,
		    opt_reply_to
		   }).

-record(late_load, {table,
		    reason,
		    opt_reply_to,
		    loaders
		   }).

-record(loader_done, {worker_pid,
		      is_loaded,
		      table_name,
		      needs_announce,
		      needs_sync,
		      needs_reply,
		      reply_to,
		      reply}).

-record(sender_done, {worker_pid,
		      worker_res,
		      table_name
		     }).

-record(dumper_done, {worker_pid,
		      worker_res
		     }).

val(Var) ->
    case ?catch_val(Var) of
	{'EXIT', Reason} -> mnesia_lib:other_val(Var, Reason); 
	Value -> Value
    end.

start() ->
    gen_server:start_link({local, ?SERVER_NAME}, ?MODULE, [self()],
			  [{timeout, infinity}
			   %% ,{debug, [trace]}
			  ]).

sync_dump_log(InitBy) ->
    call({sync_dump_log, InitBy}).

async_dump_log(InitBy) ->
    ?SERVER_NAME ! {async_dump_log, InitBy}.
    
%% Wait for tables to be active
%% If needed, we will wait for Mnesia to start
%% If Mnesia stops, we will wait for Mnesia to restart
%% We will wait even if the list of tables is empty
%%
wait_for_tables(Tabs, Timeout) when is_list(Tabs), Timeout == infinity ->
    do_wait_for_tables(Tabs, Timeout);
wait_for_tables(Tabs, Timeout) when is_list(Tabs),
                                    is_integer(Timeout), Timeout >= 0 ->
    do_wait_for_tables(Tabs, Timeout);
wait_for_tables(Tabs, Timeout) ->
    {error, {badarg, Tabs, Timeout}}.

do_wait_for_tables(Tabs, 0) ->
    reply_wait(Tabs);
do_wait_for_tables(Tabs, Timeout) ->
    Pid = spawn_link(?MODULE, wait_for_tables_init, [self(), Tabs]),
    receive
	{?SERVER_NAME, Pid, Res} ->
	    Res;
	{'EXIT', Pid, _} ->
	    reply_wait(Tabs)
    after Timeout ->
	    unlink(Pid),
	    exit(Pid, timeout),
	    reply_wait(Tabs)
    end.
	
reply_wait(Tabs) ->
    case catch mnesia_lib:active_tables() of
	{'EXIT', _} ->
	    {error, {node_not_running, node()}};
	Active when is_list(Active) ->
	    case Tabs -- Active of
		[] ->
		    ok;
		BadTabs ->
		    {timeout, BadTabs}
	    end
    end.

wait_for_tables_init(From, Tabs) ->
    process_flag(trap_exit, true),
    Res = wait_for_init(From, Tabs, whereis(?SERVER_NAME)),
    From ! {?SERVER_NAME, self(), Res},
    unlink(From),
    exit(normal).

wait_for_init(From, Tabs, Init) ->
    case catch link(Init) of
	{'EXIT', _} ->
	    %% Mnesia is not started
	    {error, {node_not_running, node()}};
	true when is_pid(Init) ->
	    cast({sync_tabs, Tabs, self()}),
	    rec_tabs(Tabs, Tabs, From, Init)
    end.

sync_reply(Waiter, Tab) ->
    Waiter ! {?SERVER_NAME, {tab_synced, Tab}}.

rec_tabs([Tab | Tabs], AllTabs, From, Init) ->
    receive
	{?SERVER_NAME, {tab_synced, Tab}} ->
	    rec_tabs(Tabs, AllTabs, From, Init);

	{'EXIT', From, _} ->
	    %% This will trigger an exit signal
	    %% to mnesia_init
	    exit(wait_for_tables_timeout);
	
	{'EXIT', Init, _} ->
	    %% Oops, mnesia_init stopped,
	    exit(mnesia_stopped)
    end;
rec_tabs([], _, _, Init) ->
    unlink(Init),
    ok.

get_remote_cstructs() ->
    get_cstructs().  %% Sigh not forward compatible always check version

%% Old function kept for backwards compatibility; converts cstructs before sending.
get_cstructs() ->
    {cstructs, Cstructs, Running} = call(get_cstructs),
    Node = node(group_leader()),
    {cstructs, mnesia_schema:normalize_cs(Cstructs, Node), Running}.

update(Fun) ->
    call({update,Fun}).


mnesia_down(Node) ->
    case cast({mnesia_down, Node}) of
	{error, _} -> mnesia_monitor:mnesia_down(?SERVER_NAME, Node);
	_Pid ->  ok
    end.
wait_for_schema_commit_lock() ->
    link(whereis(?SERVER_NAME)),
    unsafe_call(wait_for_schema_commit_lock).

block_controller() ->
    call(block_controller).

unblock_controller() ->
    cast(unblock_controller).

release_schema_commit_lock() ->
    cast({release_schema_commit_lock, self()}),
    unlink(whereis(?SERVER_NAME)).

%% Special for preparation of add table copy
get_network_copy(Tab, Cs) ->
%   We can't let the controller queue this one
%   because that may cause a deadlock between schema_operations
%   and initial tableloadings which both takes schema locks.
%   But we have to get copier_done msgs when the other side 
%   goes down.
    call({add_other, self()}),
    Reason = {dumper,add_table_copy},
    Work = #net_load{table = Tab,reason = Reason,cstruct = Cs},
    %% I'll need this cause it's linked trough the subscriber
    %% might be solved by using monitor in subscr instead.
    process_flag(trap_exit, true),
    Load = load_table_fun(Work),
    Res = (catch Load()),
    process_flag(trap_exit, false),
    call({del_other, self()}),
    case Res of
 	#loader_done{is_loaded = true} ->
 	    Tab = Res#loader_done.table_name,
 	    case Res#loader_done.needs_announce of
 		true ->
 		    i_have_tab(Tab);
 		false ->
 		    ignore
 	    end,
 	    Res#loader_done.reply;
 	#loader_done{} -> 
 	    Res#loader_done.reply;
 	Else ->
 	    {not_loaded, Else}
    end.

%% This functions is invoked from the dumper
%% 
%% There are two cases here:
%% startup ->
%%   no need for sync, since mnesia_controller not started yet
%% schema_trans ->
%%   already synced with mnesia_controller since the dumper
%%   is syncronously started from mnesia_controller

create_table(Tab) ->
    {loaded, ok} = mnesia_loader:disc_load_table(Tab, {dumper,create_table}).

get_disc_copy(Tab) ->
    disc_load_table(Tab, {dumper,change_table_copy_type}, undefined).

%% Returns ok instead of yes
force_load_table(Tab) when is_atom(Tab), Tab /= schema ->
    case ?catch_val({Tab, storage_type}) of
	ram_copies ->
	    do_force_load_table(Tab);
	disc_copies ->
	    do_force_load_table(Tab);
	disc_only_copies ->
	    do_force_load_table(Tab);
	unknown ->
	    set({Tab, load_by_force}, true),
	    cast({force_load_updated, Tab}),
	    wait_for_tables([Tab], infinity);
	{'EXIT', _} ->
	    {error, {no_exists, Tab}}
    end;
force_load_table(Tab) ->
    {error, {bad_type, Tab}}.
    
do_force_load_table(Tab) ->
    Loaded = ?catch_val({Tab, load_reason}),
    case Loaded of
	unknown -> 
	    set({Tab, load_by_force}, true),
	    mnesia_late_loader:async_late_disc_load(node(), [Tab], forced_by_user),
	    wait_for_tables([Tab], infinity);
	{'EXIT', _} ->
	    set({Tab, load_by_force}, true),
	    mnesia_late_loader:async_late_disc_load(node(), [Tab], forced_by_user),
	    wait_for_tables([Tab], infinity);
	_ ->
	    ok
    end.    
master_nodes_updated(schema, _Masters) ->
    ignore;
master_nodes_updated(Tab, Masters) ->
    cast({master_nodes_updated, Tab, Masters}).

schedule_late_disc_load(Tabs, Reason) ->
    MsgTag = late_disc_load,
    try_schedule_late_disc_load(Tabs, Reason, MsgTag).

try_schedule_late_disc_load(Tabs, _Reason, MsgTag)
  when Tabs == [], MsgTag /= schema_is_merged ->
    ignore;
try_schedule_late_disc_load(Tabs, Reason, MsgTag) ->
    GetIntents =
	fun() ->
		Item = mnesia_late_disc_load,
		Nodes = val({current, db_nodes}),
		mnesia:lock({global, Item, Nodes}, write),
		case multicall(Nodes -- [node()], disc_load_intents) of
		    {Replies, []} ->
			call({MsgTag, Tabs, Reason, Replies}),
			done;
		    {_, BadNodes} ->
			%% Some nodes did not respond, lets try again
			{retry, BadNodes}
		end
	end,
    case mnesia:transaction(GetIntents) of
	{atomic, done} ->
	    done;
	{atomic, {retry, BadNodes}} ->
	    verbose("Retry late_load_tables because bad nodes: ~p~n",
		    [BadNodes]),
	    try_schedule_late_disc_load(Tabs, Reason, MsgTag);
	{aborted, AbortReason} ->
	    fatal("Cannot late_load_tables~p: ~p~n",
		  [[Tabs, Reason, MsgTag], AbortReason])
    end.

connect_nodes(Ns) ->
    connect_nodes(Ns, fun default_merge/1).

connect_nodes(Ns, UserFun) ->
    case mnesia:system_info(is_running) of 
	no ->
	    {error, {node_not_running, node()}};
	yes ->	  	   
	    Pid = spawn_link(?MODULE,connect_nodes2,[self(),Ns, UserFun]),
	    receive 
		{?MODULE, Pid, Res, New} -> 
		    case Res of
			ok -> 
			    mnesia_lib:add_list(extra_db_nodes, New),
			    {ok, New};
			{aborted, {throw, Str}} when is_list(Str) ->
			    %%mnesia_recover:disconnect_nodes(New),
			    {error, {merge_schema_failed, lists:flatten(Str)}};
			Else ->
			    {error, Else}
		    end;	    
		{'EXIT', Pid, Reason} -> 
		    {error, Reason}
	    end
    end.

connect_nodes2(Father, Ns, UserFun) ->
    Current = val({current, db_nodes}),
    abcast([node()|Ns], {merging_schema, node()}),
    {NewC, OldC} = mnesia_recover:connect_nodes(Ns),
    Connected = NewC ++OldC,
    New1 = mnesia_lib:intersect(Ns, Connected),
    New = New1 -- Current,    
    process_flag(trap_exit, true),
    Res = try_merge_schema(New, [], UserFun),
    Msg = {schema_is_merged, [], late_merge, []},
    multicall([node()|Ns], Msg),
    After = val({current, db_nodes}),    
    Father ! {?MODULE, self(), Res, mnesia_lib:intersect(Ns,After)},
    unlink(Father),
    ok.
    
%% Merge the local schema with the schema on other nodes.
%% But first we must let all processes that want to force
%% load tables wait until the schema merge is done.

merge_schema() ->
    AllNodes = mnesia_lib:all_nodes(),
    case try_merge_schema(AllNodes, [node()], fun default_merge/1) of
	ok -> 
	    schema_is_merged();
	{aborted, {throw, Str}} when is_list(Str) ->
	    fatal("Failed to merge schema: ~s~n", [Str]);
	Else ->
	    fatal("Failed to merge schema: ~p~n", [Else])
    end.

default_merge(F) ->
    F([]).

try_merge_schema(Nodes, Told0, UserFun) ->
    case mnesia_schema:merge_schema(UserFun) of
	{atomic, not_merged} ->
	    %% No more nodes that we need to merge the schema with
	    %% Ensure we have told everybody that we are running
	    case val({current,db_nodes}) -- mnesia_lib:uniq(Told0) of
		[] ->  ok;
		Tell ->
		    im_running(Tell, [node()]),
		    ok
	    end;
	{atomic, {merged, OldFriends, NewFriends}} ->
	    %% Check if new nodes has been added to the schema
	    Diff = mnesia_lib:all_nodes() -- [node() | Nodes],
	    mnesia_recover:connect_nodes(Diff),

	    %% Tell everybody to adopt orphan tables
	    im_running(OldFriends, NewFriends),
	    im_running(NewFriends, OldFriends),
	    Told = case lists:member(node(), NewFriends) of
		       true -> Told0 ++ OldFriends;
		       false -> Told0 ++ NewFriends
		   end,
	    try_merge_schema(Nodes, Told, UserFun);
	{atomic, {"Cannot get cstructs", Node, Reason}} ->
	    dbg_out("Cannot get cstructs, Node ~p ~p~n", [Node, Reason]),
	    timer:sleep(300), % Avoid a endless loop look alike
	    try_merge_schema(Nodes, Told0, UserFun);
	{aborted, {shutdown, _}} ->  %% One of the nodes is going down
	    timer:sleep(300), % Avoid a endless loop look alike
	    try_merge_schema(Nodes, Told0, UserFun);
	Other ->
	    Other
    end.

im_running(OldFriends, NewFriends) ->
    abcast(OldFriends, {im_running, node(), NewFriends}).

schema_is_merged() ->
    MsgTag = schema_is_merged,
    SafeLoads = initial_safe_loads(),
    
    %% At this point we do not know anything about
    %% which tables that the other nodes already
    %% has loaded and therefore we let the normal
    %% processing of the loader_queue take care
    %% of it, since we at that time point will
    %% know the whereabouts. We rely on the fact
    %% that all nodes tells each other directly
    %% when they have loaded a table and are
    %% willing to share it.
    
    try_schedule_late_disc_load(SafeLoads, initial, MsgTag).


cast(Msg) ->
    case whereis(?SERVER_NAME) of
	undefined ->{error, {node_not_running, node()}};
	Pid ->  gen_server:cast(Pid, Msg)
    end.

abcast(Nodes, Msg) ->
    gen_server:abcast(Nodes, ?SERVER_NAME, Msg).

unsafe_call(Msg) ->
    case whereis(?SERVER_NAME) of
	undefined -> {error, {node_not_running, node()}};
	Pid -> gen_server:call(Pid, Msg, infinity)
    end.

call(Msg) ->
    case whereis(?SERVER_NAME) of
	undefined ->
	    {error, {node_not_running, node()}};
	Pid ->
	    link(Pid),
	    Res = gen_server:call(Pid, Msg, infinity),
	    unlink(Pid),

	    %% We get an exit signal if server dies
            receive
                {'EXIT', Pid, _Reason} ->
                    {error, {node_not_running, node()}}
            after 0 ->
                    Res
            end
    end.

remote_call(Node, Func, Args) ->
    case catch gen_server:call({?MODULE, Node}, {Func, Args, self()}, infinity) of
	{'EXIT', Error} ->
	    {error, Error};
	Else ->
	    Else
    end.
    
multicall(Nodes, Msg) ->
    {Good, Bad} = gen_server:multi_call(Nodes, ?MODULE, Msg, infinity),
    PatchedGood = [Reply || {_Node, Reply} <- Good],
    {PatchedGood, Bad}.  %% Make the replies look like rpc:multicalls..
%%    rpc:multicall(Nodes, ?MODULE, call, [Msg]).

%%%----------------------------------------------------------------------
%%% Callback functions from gen_server
%%%----------------------------------------------------------------------

%%----------------------------------------------------------------------
%% Func: init/1
%% Returns: {ok, State}          |
%%          {ok, State, Timeout} |
%%          {stop, Reason}
%%----------------------------------------------------------------------
init([Parent]) ->
    process_flag(trap_exit, true),
    mnesia_lib:verbose("~p starting: ~p~n", [?SERVER_NAME, self()]),

    %% Handshake and initialize transaction recovery
    %% for new nodes detected in the schema
    All = mnesia_lib:all_nodes(),
    Diff = All -- [node() | val(original_nodes)],
    mnesia_lib:unset(original_nodes),
    mnesia_recover:connect_nodes(Diff),

    Interval = mnesia_monitor:get_env(dump_log_time_threshold),
    Msg = {async_dump_log, time_threshold},
    {ok, Ref} = timer:send_interval(Interval, Msg),
    mnesia_dumper:start_regulator(),
    
    Empty = gb_trees:empty(),
    {ok, #state{supervisor = Parent, dump_log_timer_ref = Ref, 
		loader_queue = Empty,
		late_loader_queue = Empty}}.

%%----------------------------------------------------------------------
%% Func: handle_call/3
%% Returns: {reply, Reply, State}          |
%%          {reply, Reply, State, Timeout} |
%%          {noreply, State}               |
%%          {noreply, State, Timeout}      |
%%          {stop, Reason, Reply, State}   | (terminate/2 is called)
%%          {stop, Reason, Reply, State}     (terminate/2 is called)
%%----------------------------------------------------------------------

handle_call({sync_dump_log, InitBy}, From, State) ->
    Worker = #dump_log{initiated_by = InitBy,
		       opt_reply_to = From
		      },
    State2 = add_worker(Worker, State),
    noreply(State2);

handle_call(wait_for_schema_commit_lock, From, State) ->
    Worker = #schema_commit_lock{owner = From},
    State2 = add_worker(Worker, State),
    noreply(State2);

handle_call(block_controller, From, State) ->
    Worker = #block_controller{owner = From},
    State2 = add_worker(Worker, State),
    noreply(State2);

handle_call({update,Fun}, From, State) ->
    Res = (catch Fun()),
    reply(From, Res), 
    noreply(State);

handle_call(get_cstructs, From, State) ->
    Tabs = val({schema, tables}),
    Cstructs = [val({T, cstruct}) || T <- Tabs],
    Running = val({current, db_nodes}),
    reply(From, {cstructs, Cstructs, Running}), 
    noreply(State);

handle_call({schema_is_merged, [], late_merge, []}, From, 
	    State = #state{schema_is_merged = Merged}) ->
    case Merged of
	{false, Node} when Node == node(From) ->
	    Msgs = State#state.early_msgs,
	    State1 = State#state{early_msgs = [], schema_is_merged = true},
	    handle_early_msgs(lists:reverse(Msgs), State1);
	_ ->
	    %% Ooops this came to early, before we have merged :-)
	    %% or it came to late or from a node we don't care about
	    reply(From, ignore),
	    noreply(State)
    end;

handle_call({schema_is_merged, TabsR, Reason, RemoteLoaders}, From, State) ->
    State2 = late_disc_load(TabsR, Reason, RemoteLoaders, From, State),

    %% Handle early messages
    Msgs = State2#state.early_msgs,
    State3 = State2#state{early_msgs = [], schema_is_merged = true},
    handle_early_msgs(lists:reverse(Msgs), State3);

handle_call(disc_load_intents,From,State = #state{loader_queue=LQ,late_loader_queue=LLQ}) ->
    LQTabs  = gb_trees:keys(LQ),
    LLQTabs = gb_trees:keys(LLQ),
    ActiveTabs = lists:sort(mnesia_lib:local_active_tables()),
    reply(From, {ok, node(), ordsets:union([LQTabs,LLQTabs,ActiveTabs])}),
    noreply(State);

handle_call({update_where_to_write, [add, Tab, AddNode], _From}, _Dummy, State) ->
    Current = val({current, db_nodes}),
    Res = 
	case lists:member(AddNode, Current) and 
	    (State#state.schema_is_merged == true) of
	    true ->
		mnesia_lib:add_lsort({Tab, where_to_write}, AddNode),
		update_where_to_wlock(Tab);
	    false ->
		ignore
	end,
    {reply, Res, State};

handle_call({add_active_replica, [Tab, ToNode, RemoteS, AccessMode], From},
	    ReplyTo, State) ->
    KnownNode = lists:member(ToNode, val({current, db_nodes})),
    Merged = State#state.schema_is_merged,
    if
	KnownNode == false ->
	    reply(ReplyTo, ignore),
	    noreply(State);
	Merged == true ->
	    Res = case ?catch_val({Tab, cstruct}) of
		      {'EXIT', _} ->  %% Tab deleted
			  deleted;
		      _ ->
			  add_active_replica(Tab, ToNode, RemoteS, AccessMode)
		  end,
	    reply(ReplyTo, Res),
	    noreply(State);
	true -> %% Schema is not merged
	    Msg = {add_active_replica, [Tab, ToNode, RemoteS, AccessMode], From},
	    Msgs = State#state.early_msgs,
	    reply(ReplyTo, ignore),   %% Reply ignore and add data after schema merge
	    noreply(State#state{early_msgs = [{call, Msg, undefined} | Msgs]})
    end;

handle_call({unannounce_add_table_copy, [Tab, Node], From}, ReplyTo, State) ->    
    KnownNode = lists:member(node(From), val({current, db_nodes})),
    Merged = State#state.schema_is_merged,
    if
	KnownNode == false ->
	    reply(ReplyTo, ignore),
	    noreply(State);
	Merged == true ->
	    Res = unannounce_add_table_copy(Tab, Node),
	    reply(ReplyTo, Res),
	    noreply(State);
	true -> %% Schema is not merged
	    Msg = {unannounce_add_table_copy, [Tab, Node], From},
	    Msgs = State#state.early_msgs,
	    reply(ReplyTo, ignore),   %% Reply ignore and add data after schema merge
	    %% Set ReplyTO to undefined so we don't reply twice
	    noreply(State#state{early_msgs = [{call, Msg, undefined} | Msgs]})
    end;

handle_call({net_load, Tab, Cs}, From, State) ->
    State2 = 
	case State#state.schema_is_merged of
	    true -> 	    
		Worker = #net_load{table = Tab,
				   opt_reply_to = From,
				   reason = {dumper,add_table_copy},
				   cstruct = Cs
				  },
		add_worker(Worker, State);
	    false -> 
		reply(From, {not_loaded, schema_not_merged}),
		State
	end,
    noreply(State2);

handle_call(Msg, From, State) when State#state.schema_is_merged /= true ->
    %% Buffer early messages
    Msgs = State#state.early_msgs,
    noreply(State#state{early_msgs = [{call, Msg, From} | Msgs]});

handle_call({late_disc_load, Tabs, Reason, RemoteLoaders}, From, State) ->
    State2 = late_disc_load(Tabs, Reason, RemoteLoaders, From, State),
    noreply(State2);

handle_call({unblock_table, Tab}, _Dummy, State) ->
    Var = {Tab, where_to_commit},
    case val(Var) of
	{blocked, List} ->
	    set(Var, List); % where_to_commit
	_ ->
	    ignore
    end,
    {reply, ok, State};

handle_call({block_table, [Tab], From}, _Dummy, State) ->
    case lists:member(node(From), val({current, db_nodes})) of
	true ->
	    block_table(Tab);
	false ->
	    ignore
    end,
    {reply, ok, State};

handle_call({check_w2r, _Node, Tab}, _From, State) ->
    {reply, val({Tab, where_to_read}), State};

handle_call({add_other, Who}, _From, State = #state{others=Others0}) ->
    Others = [Who|Others0],
    {reply, ok, State#state{others=Others}};
handle_call({del_other, Who}, _From, State = #state{others=Others0}) ->
    Others = lists:delete(Who, Others0),
    {reply, ok, State#state{others=Others}};
	    
handle_call(Msg, _From, State) ->
    error("~p got unexpected call: ~p~n", [?SERVER_NAME, Msg]),
    noreply(State).

late_disc_load(TabsR, Reason, RemoteLoaders, From, 
	       State = #state{loader_queue = LQ, late_loader_queue = LLQ}) ->
    verbose("Intend to load tables: ~p~n", [TabsR]),
    ?eval_debug_fun({?MODULE, late_disc_load},
		    [{tabs, TabsR}, 
		     {reason, Reason},
		     {loaders, RemoteLoaders}]),

    reply(From, queued),
    %% RemoteLoaders is a list of {ok, Node, Tabs} tuples

    %% Remove deleted tabs and queued/loaded
    LocalTabs = gb_sets:from_ordset(lists:sort(mnesia_lib:val({schema,local_tables}))),
    Filter = fun(TabInfo0, Acc) -> 
		     TabInfo = {Tab,_} = 
			 case TabInfo0 of 
			     {_,_} -> TabInfo0;
			     TabN -> {TabN,Reason}
			 end,
		     case gb_sets:is_member(Tab, LocalTabs) of
			 true -> 
			     case ?catch_val({Tab, where_to_read}) == node() of
				 true -> Acc;
				 false ->
				     case gb_trees:is_defined(Tab,LQ) of
					 true ->  Acc;
					 false -> [TabInfo | Acc]
				     end
			     end;
			 false -> Acc
		     end
	     end,
    
    Tabs = lists:foldl(Filter, [], TabsR),
    
    Nodes = val({current, db_nodes}),
    LateQueue = late_loaders(Tabs, RemoteLoaders, Nodes, LLQ),
    State#state{late_loader_queue = LateQueue}. 

late_loaders([{Tab, Reason} | Tabs], RemoteLoaders, Nodes, LLQ) ->
    case gb_trees:is_defined(Tab, LLQ) of
	false ->
	    LoadNodes = late_load_filter(RemoteLoaders, Tab, Nodes, []),
	    case LoadNodes of
		[] ->  cast({disc_load, Tab, Reason}); % Ugly cast
		_ ->   ignore
	    end,
	    LateLoad = #late_load{table=Tab,loaders=LoadNodes,reason=Reason},
	    late_loaders(Tabs, RemoteLoaders, Nodes, gb_trees:insert(Tab,LateLoad,LLQ));
	true ->
	    late_loaders(Tabs, RemoteLoaders, Nodes, LLQ)	     
    end;
late_loaders([], _RemoteLoaders, _Nodes, LLQ) ->
    LLQ.

late_load_filter([{error, _} | RemoteLoaders], Tab, Nodes, Acc) ->
    late_load_filter(RemoteLoaders, Tab, Nodes, Acc);
late_load_filter([{badrpc, _} | RemoteLoaders], Tab, Nodes, Acc) ->
    late_load_filter(RemoteLoaders, Tab, Nodes, Acc);
late_load_filter([RL | RemoteLoaders], Tab, Nodes, Acc) ->
    {ok, Node, Intents} = RL,
    Access = val({Tab, access_mode}),
    LocalC = val({Tab, local_content}),
    StillActive = lists:member(Node, Nodes),
    RemoteIntent = lists:member(Tab, Intents),
    if
	Access == read_write,
	LocalC == false,
	StillActive == true,
	RemoteIntent == true ->
	    Masters = mnesia_recover:get_master_nodes(Tab),
	    case lists:member(Node, Masters) of
		true ->
		    %% The other node is master node for
		    %% the table, accept his load intent
		    late_load_filter(RemoteLoaders, Tab, Nodes, [Node | Acc]);
		false when Masters == [] ->
		    %% The table has no master nodes
		    %% accept his load intent
		    late_load_filter(RemoteLoaders, Tab, Nodes, [Node | Acc]);
		false ->
		    %% Some one else is master node for
		    %% the table, ignore his load intent
		    late_load_filter(RemoteLoaders, Tab, Nodes, Acc)
	    end;
	true ->
	    late_load_filter(RemoteLoaders, Tab, Nodes, Acc)
    end;
late_load_filter([], _Tab, _Nodes, Acc) ->
    Acc.
    
%%----------------------------------------------------------------------
%% Func: handle_cast/2
%% Returns: {noreply, State}          |
%%          {noreply, State, Timeout} |
%%          {stop, Reason, State}            (terminate/2 is called)
%%----------------------------------------------------------------------

handle_cast({release_schema_commit_lock, _Owner}, State) ->
    if
	State#state.is_stopping == true ->
	    {stop, shutdown, State};
	true -> 
	    case State#state.dumper_queue of
		[#schema_commit_lock{}|Rest] ->
		    [_Worker | Rest] = State#state.dumper_queue,
		    State2 = State#state{dumper_pid = undefined,
					 dumper_queue = Rest},
		    State3 = opt_start_worker(State2),
		    noreply(State3);
		_ ->
		    noreply(State)
	    end
    end;

handle_cast(unblock_controller, State) ->
    if
	State#state.is_stopping == true ->
	    {stop, shutdown, State};
	is_record(hd(State#state.dumper_queue), block_controller) ->
	    [_Worker | Rest] = State#state.dumper_queue,
	    State2 = State#state{dumper_pid = undefined,
				 dumper_queue = Rest},
	    State3 = opt_start_worker(State2),	    
	    noreply(State3)
    end;

handle_cast({mnesia_down, Node}, State) ->
    maybe_log_mnesia_down(Node),
    mnesia_lib:del({current, db_nodes}, Node),
    mnesia_lib:unset({node_up, Node}),
    mnesia_checkpoint:tm_mnesia_down(Node),
    Alltabs = val({schema, tables}),
    reconfigure_tables(Node, Alltabs),
    %% Done from (external point of view)
    mnesia_monitor:mnesia_down(?SERVER_NAME, Node),

    %% Fix if we are late_merging against the node that went down
    case State#state.schema_is_merged of
	{false, Node} -> 
	    spawn(?MODULE, call, [{schema_is_merged, [], late_merge, []}]);
	_ ->
	    ignore
    end,
    
    %% Fix internal stuff
    LateQ = remove_loaders(Alltabs, Node, State#state.late_loader_queue),
    
    case get_senders(State) ++ get_loaders(State) of
	[] -> ignore;
	Senders -> 
	    lists:foreach(fun({Pid,_}) -> Pid ! {copier_done, Node} end,
			  Senders)
    end,
    lists:foreach(fun(Pid) -> Pid ! {copier_done,Node} end, 
		  State#state.others),
    
    Remove = fun(ST) ->
		     node(ST#send_table.receiver_pid) /= Node
	     end,
    NewSenders = lists:filter(Remove, State#state.sender_queue),
    Early = remove_early_messages(State#state.early_msgs, Node),
    noreply(State#state{sender_queue = NewSenders, 
			early_msgs = Early, 
			late_loader_queue = LateQ
		       });

handle_cast({merging_schema, Node}, State) ->
    case State#state.schema_is_merged of
	false ->
	    %% This comes from dynamic connect_nodes which are made
	    %% after mnesia:start() and the schema_merge.
	    ImANewKidInTheBlock = 
		(val({schema, storage_type}) == ram_copies) 
		andalso (mnesia_lib:val({schema, local_tables}) == [schema]),
	    case ImANewKidInTheBlock of
		true ->  %% I'm newly started ram_node..
		    noreply(State#state{schema_is_merged = {false, Node}});
		false ->
		    noreply(State)
	    end;
	_ -> %% Already merging schema.
	    noreply(State)
    end;

handle_cast(Msg, State) when State#state.schema_is_merged /= true ->
    %% Buffer early messages
    Msgs = State#state.early_msgs,
    noreply(State#state{early_msgs = [{cast, Msg} | Msgs]});

%% This must be done after schema_is_merged otherwise adopt_orphan
%% might trigger a table load from wrong nodes as a result of that we don't 
%% know which tables we can load safly first.
handle_cast({im_running, Node, NewFriends}, State) ->
    LocalTabs = mnesia_lib:local_active_tables() -- [schema],
    RemoveLocalOnly = fun(Tab) -> not val({Tab, local_content}) end,
    Tabs = lists:filter(RemoveLocalOnly, LocalTabs),
    Nodes = mnesia_lib:union([Node],val({current, db_nodes})),
    Ns = mnesia_lib:intersect(NewFriends, Nodes),
    abcast(Ns, {adopt_orphans, node(), Tabs}),
    noreply(State);

handle_cast({disc_load, Tab, Reason}, State) ->
    Worker = #disc_load{table = Tab, reason = Reason},
    State2 = add_worker(Worker, State),
    noreply(State2);

handle_cast(Worker = #send_table{}, State) ->
    State2 = add_worker(Worker, State),
    noreply(State2);

handle_cast({sync_tabs, Tabs, From}, State) ->
    %% user initiated wait_for_tables
    handle_sync_tabs(Tabs, From),
    noreply(State);

handle_cast({i_have_tab, Tab, Node}, State) ->
    case lists:member(Node, val({current, db_nodes})) of
	true -> 
	    State2 = node_has_tabs([Tab], Node, State),
	    noreply(State2);
	false ->
	    noreply(State)
    end;

handle_cast({force_load_updated, Tab}, State) ->
    case val({Tab, active_replicas}) of
	[] ->
	    %% No valid replicas
	    noreply(State);
	[SomeNode | _] ->
	    State2 = node_has_tabs([Tab], SomeNode, State),
	    noreply(State2)
    end;
    
handle_cast({master_nodes_updated, Tab, Masters}, State) ->
    Active = val({Tab, active_replicas}),
    Valid = 
	case val({Tab, load_by_force}) of
	    true ->
		Active;
	    false ->
		if
		    Masters == [] ->
			Active;
		    true ->
			mnesia_lib:intersect(Masters, Active)
		end
	end,
    case Valid of
	[] ->
	    %% No valid replicas
	    noreply(State);
	[SomeNode | _] ->
	    State2 = node_has_tabs([Tab], SomeNode, State),
	    noreply(State2)
    end;
    
handle_cast({adopt_orphans, Node, Tabs}, State) ->
    State2 = node_has_tabs(Tabs, Node, State),
    
    case ?catch_val({node_up,Node}) of
	true -> ignore;
	_ ->
	    %% Register the other node as up and running
	    set({node_up, Node}, true),
	    mnesia_recover:log_mnesia_up(Node),
	    verbose("Logging mnesia_up ~w~n",[Node]),
	    mnesia_lib:report_system_event({mnesia_up, Node}),
	    %% Load orphan tables
	    LocalTabs = val({schema, local_tables}) -- [schema],
	    Nodes = val({current, db_nodes}),
	    {LocalOrphans, RemoteMasters} =
		orphan_tables(LocalTabs, Node, Nodes, [], []),
	    Reason = {adopt_orphan, node()},
	    mnesia_late_loader:async_late_disc_load(node(), LocalOrphans, Reason),

	    Fun =
		fun(N) ->
			RemoteOrphans =
			    [Tab || {Tab, Ns} <- RemoteMasters,
				    lists:member(N, Ns)],
			mnesia_late_loader:maybe_async_late_disc_load(N, RemoteOrphans, Reason)
		end,
	    lists:foreach(Fun, Nodes)
    end,
    noreply(State2);

handle_cast(Msg, State) ->
    error("~p got unexpected cast: ~p~n", [?SERVER_NAME, Msg]),
    noreply(State).

handle_sync_tabs([Tab | Tabs], From) ->    
    case val({Tab, where_to_read}) of
	nowhere ->
	    case get({sync_tab, Tab}) of
		undefined ->
		    put({sync_tab, Tab}, [From]);
		Pids ->
		    put({sync_tab, Tab}, [From | Pids])
	    end;
	_ ->
	    sync_reply(From, Tab)
    end,
    handle_sync_tabs(Tabs, From);
handle_sync_tabs([], _From) ->
    ok.

%%----------------------------------------------------------------------
%% Func: handle_info/2
%% Returns: {noreply, State}          |
%%          {noreply, State, Timeout} |
%%          {stop, Reason, State}            (terminate/2 is called)
%%----------------------------------------------------------------------

handle_info({async_dump_log, InitBy}, State) ->
    Worker = #dump_log{initiated_by = InitBy},
    State2 = add_worker(Worker, State),
    noreply(State2);

handle_info(#dumper_done{worker_pid=Pid, worker_res=Res}, State) ->
    if
	State#state.is_stopping == true ->
	    {stop, shutdown, State};
	Res == dumped, Pid == State#state.dumper_pid ->
	    [Worker | Rest] = State#state.dumper_queue,
	    reply(Worker#dump_log.opt_reply_to, Res),
	    State2 = State#state{dumper_pid = undefined,
				 dumper_queue = Rest},
	    State3 = opt_start_worker(State2),
	    noreply(State3);
	true ->
	    fatal("Dumper failed: ~p~n state: ~p~n", [Res, State]),
	    {stop, fatal, State}
    end;

handle_info(Done = #loader_done{worker_pid=WPid, table_name=Tab}, State0) ->    
    LateQueue0 = State0#state.late_loader_queue,
    State1 = State0#state{loader_pid = lists:keydelete(WPid,1,get_loaders(State0))},

    State2 =
	case Done#loader_done.is_loaded of
	    true ->
		%% Optional table announcement
		if 
		    Done#loader_done.needs_announce == true,
		    Done#loader_done.needs_reply == true ->
			i_have_tab(Tab),
			%% Should be {dumper,add_table_copy} only
			reply(Done#loader_done.reply_to,
			      Done#loader_done.reply);
		    Done#loader_done.needs_reply == true ->
			%% Should be {dumper,add_table_copy} only
			reply(Done#loader_done.reply_to,
			      Done#loader_done.reply);
		    Done#loader_done.needs_announce == true, Tab == schema ->
			i_have_tab(Tab);
		    Done#loader_done.needs_announce == true ->
			i_have_tab(Tab),
			%% Local node needs to perform user_sync_tab/1
			Ns = val({current, db_nodes}),
			abcast(Ns, {i_have_tab, Tab, node()});
		    Tab == schema ->
			ignore;
		    true ->
			%% Local node needs to perform user_sync_tab/1
			Ns = val({current, db_nodes}),
			AlreadyKnows = val({Tab, active_replicas}),
			abcast(Ns -- AlreadyKnows, {i_have_tab, Tab, node()})
		end,
		%% Optional user sync
		case Done#loader_done.needs_sync of
		    true -> user_sync_tab(Tab);
		    false -> ignore
		end,
		State1#state{late_loader_queue=gb_trees:delete_any(Tab, LateQueue0)};
	    false ->
		%% Either the node went down or table was not
		%% loaded remotly yet 
		case Done#loader_done.needs_reply of
		    true ->
			reply(Done#loader_done.reply_to,
			      Done#loader_done.reply);
		    false ->
			ignore
		end,
		case ?catch_val({Tab, active_replicas}) of
		    [_|_] -> % still available elsewhere
			{value,{_,Worker}} = lists:keysearch(WPid,1,get_loaders(State0)),
			add_loader(Tab,Worker,State1);
		    _ ->
			State1
		end
	end,
    State3 = opt_start_worker(State2),
    noreply(State3);

handle_info(#sender_done{worker_pid=Pid, worker_res=Res}, State)  ->
    Senders = get_senders(State),
    {value, {Pid,_Worker}} = lists:keysearch(Pid, 1, Senders),
    if
	Res == ok ->	    
	    State2 = State#state{sender_pid = lists:keydelete(Pid, 1, Senders)},
	    State3 = opt_start_worker(State2),
	    noreply(State3);
	true ->
	    %% No need to send any message to the table receiver
	    %% since it will soon get a mnesia_down anyway
	    fatal("Sender failed: ~p~n state: ~p~n", [Res, State]),
	    {stop, fatal, State}
    end;

handle_info({'EXIT', Pid, R}, State) when Pid == State#state.supervisor ->
    catch set(mnesia_status, stopping),
    case State#state.dumper_pid of
	undefined ->
	    dbg_out("~p was ~p~n", [?SERVER_NAME, R]),
	    {stop, shutdown, State};
	_ ->
	    noreply(State#state{is_stopping = true})
    end;

handle_info({'EXIT', Pid, R}, State) when Pid == State#state.dumper_pid ->
    case State#state.dumper_queue of
	[#schema_commit_lock{}|Workers] -> %% Schema trans crashed or was killed
	    dbg_out("WARNING: Dumper ~p exited ~p~n", [Pid, R]),
	    State2 = State#state{dumper_queue = Workers, dumper_pid = undefined},
	    State3 = opt_start_worker(State2),
	    noreply(State3);
	_Other ->
	    fatal("Dumper or schema commit crashed: ~p~n state: ~p~n", [R, State]),
	    {stop, fatal, State}
    end;

handle_info(Msg = {'EXIT', Pid, R}, State) when R /= wait_for_tables_timeout ->
    case lists:keymember(Pid, 1, get_senders(State)) of
	true ->
	    %% No need to send any message to the table receiver
	    %% since it will soon get a mnesia_down anyway
	    fatal("Sender crashed: ~p~n state: ~p~n", [{Pid,R}, State]),
	    {stop, fatal, State};
	false ->
	    case lists:keymember(Pid, 1, get_loaders(State)) of
		true -> 
		    fatal("Loader crashed: ~p~n state: ~p~n", [R, State]),
		    {stop, fatal, State};
		false ->
		    error("~p got unexpected info: ~p~n", [?SERVER_NAME, Msg]),
		    noreply(State)
	    end
    end;

handle_info({From, get_state}, State) ->
    From ! {?SERVER_NAME, State},
    noreply(State);

%% No real need for buffering
handle_info(Msg, State) when State#state.schema_is_merged /= true ->
    %% Buffer early messages
    Msgs = State#state.early_msgs,
    noreply(State#state{early_msgs = [{info, Msg} | Msgs]});

handle_info({'EXIT', Pid, wait_for_tables_timeout}, State) ->
    sync_tab_timeout(Pid, get()),
    noreply(State);

handle_info(Msg, State) ->
    error("~p got unexpected info: ~p~n", [?SERVER_NAME, Msg]),
    noreply(State).

sync_tab_timeout(Pid, [{{sync_tab, Tab}, Pids} | Tail]) ->
    case lists:delete(Pid, Pids) of
	[] ->
	    erase({sync_tab, Tab});
	Pids2 ->
	    put({sync_tab, Tab}, Pids2)
    end,
    sync_tab_timeout(Pid, Tail);
sync_tab_timeout(Pid, [_ | Tail]) ->
    sync_tab_timeout(Pid, Tail);
sync_tab_timeout(_Pid, []) ->
    ok.

%% Pick the load record that has the highest load order
%% Returns {BestLoad, RemainingQueue} or {none, []} if queue is empty
pick_next(Queue) ->
    List = gb_trees:values(Queue),
    case pick_next(List, none, none) of
	none -> {none, gb_trees:empty()};
	{Tab, Worker} -> {Worker, gb_trees:delete(Tab,Queue)}
    end.

pick_next([Head = #net_load{table=Tab}| Tail], Load, Order) ->
    select_best(Head, Tail, ?catch_val({Tab, load_order}), Load, Order);
pick_next([Head = #disc_load{table=Tab}| Tail], Load, Order) ->
    select_best(Head, Tail, ?catch_val({Tab, load_order}), Load, Order);
pick_next([], none, _Order) ->
    none;
pick_next([], Load, _Order) ->
    {element(2,Load), Load}.

select_best(_Head, Tail, {'EXIT', _WHAT}, Load, Order) ->
    %% Table have been deleted drop it.
    pick_next(Tail, Load, Order);
select_best(Load, Tail, Order, none, none) ->
    pick_next(Tail, Load, Order);
select_best(Load, Tail, Order, _OldLoad, OldOrder) when Order > OldOrder ->
    pick_next(Tail, Load, Order);
select_best(_Load, Tail, _Order, OldLoad, OldOrder) ->
    pick_next(Tail, OldLoad, OldOrder).

%%----------------------------------------------------------------------
%% Func: terminate/2
%% Purpose: Shutdown the server
%% Returns: any (ignored by gen_server)
%%----------------------------------------------------------------------
terminate(Reason, State) ->
    mnesia_monitor:terminate_proc(?SERVER_NAME, Reason, State).

%%----------------------------------------------------------------------
%% Func: code_change/3
%% Purpose: Upgrade process when its code is to be changed
%% Returns: {ok, NewState}
%%----------------------------------------------------------------------
code_change(_OldVsn, State0, _Extra) ->
    %% Loader Queue
    State1 = case State0#state.loader_pid of
		 Pids when is_list(Pids) -> State0;
		 undefined -> State0#state{loader_pid = [],loader_queue=gb_trees:empty()};
		 Pid when is_pid(Pid) -> 
		     [Loader|Rest] = State0#state.loader_queue,
		     LQ0 = [{element(2,Rec),Rec} || Rec <- Rest],
		     LQ1 = lists:sort(LQ0),
		     LQ  = gb_trees:from_orddict(LQ1),
		     State0#state{loader_pid=[{Pid,Loader}], loader_queue=LQ}
	     end,
    %% LateLoaderQueue
    State = if is_list(State1#state.late_loader_queue) -> 
		    LLQ0 = State1#state.late_loader_queue,
		    LLQ1 = lists:sort([{element(2,Rec),Rec} || Rec <- LLQ0]),
		    LLQ  = gb_trees:from_orddict(LLQ1),
		    State1#state{late_loader_queue=LLQ};
	       true ->
		    State1
	    end,
    {ok, State}.
 
%%%----------------------------------------------------------------------
%%% Internal functions
%%%----------------------------------------------------------------------

maybe_log_mnesia_down(N) ->
    %% We use mnesia_down when deciding which tables to load locally,
    %% so if we are not running (i.e haven't decided which tables
    %% to load locally), don't log mnesia_down yet.
    case mnesia_lib:is_running() of
	yes -> 
	    verbose("Logging mnesia_down ~w~n", [N]),
	    mnesia_recover:log_mnesia_down(N),
	    ok;
	_ ->	    	    
	    Filter = fun(Tab) ->
			     inactive_copy_holders(Tab, N)
		     end,
	    HalfLoadedTabs = lists:any(Filter, val({schema, local_tables}) -- [schema]),
	    if 
		HalfLoadedTabs == true ->
		    verbose("Logging mnesia_down ~w~n", [N]),
		    mnesia_recover:log_mnesia_down(N),
		    ok;		
		true ->
		    %% Unfortunately we have not loaded some common
		    %% tables yet, so we cannot rely on the nodedown
		    log_later   %% BUGBUG handle this case!!!
	    end
    end.

inactive_copy_holders(Tab, Node) ->
    Cs = val({Tab, cstruct}),
    case mnesia_lib:cs_to_storage_type(Node, Cs) of
	unknown ->
	    false;
	_Storage ->
	    mnesia_lib:not_active_here(Tab)
    end.

orphan_tables([Tab | Tabs], Node, Ns, Local, Remote) ->
    Cs = val({Tab, cstruct}),
    CopyHolders = mnesia_lib:copy_holders(Cs),
    RamCopyHolders = Cs#cstruct.ram_copies,
    DiscCopyHolders = CopyHolders -- RamCopyHolders,
    DiscNodes = val({schema, disc_copies}),
    LocalContent = Cs#cstruct.local_content,
    RamCopyHoldersOnDiscNodes = mnesia_lib:intersect(RamCopyHolders, DiscNodes),
    Active = val({Tab, active_replicas}),
    BeingCreated = (?catch_val({Tab, create_table}) == true),
    Read = val({Tab, where_to_read}),
    case lists:member(Node, DiscCopyHolders) of
	_ when BeingCreated == true -> 
	    orphan_tables(Tabs, Node, Ns, Local, Remote);
	_ when Read == node() -> %% Allready loaded
	    orphan_tables(Tabs, Node, Ns, Local, Remote);
	true when Active == [] ->
	    case DiscCopyHolders -- Ns of
		[] ->
		    %% We're last up and the other nodes have not
		    %% loaded the table. Lets load it if we are
		    %% the smallest node.
		    case lists:min(DiscCopyHolders) of
			Min when Min == node() ->
			    case mnesia_recover:get_master_nodes(Tab) of
				[] ->
				    L = [Tab | Local],
				    orphan_tables(Tabs, Node, Ns, L, Remote);
				Masters ->
				    R = [{Tab, Masters} | Remote],
				    orphan_tables(Tabs, Node, Ns, Local, R)
			    end;
			_ ->
			    orphan_tables(Tabs, Node, Ns, Local, Remote)
		    end;
		_ ->
		    orphan_tables(Tabs, Node, Ns, Local, Remote)
	    end;
	false when Active == [], DiscCopyHolders == [], RamCopyHoldersOnDiscNodes == [] ->
	    %% Special case when all replicas resides on disc less nodes
	    orphan_tables(Tabs, Node, Ns, [Tab | Local], Remote);
	_ when LocalContent == true ->
	    orphan_tables(Tabs, Node, Ns, [Tab | Local], Remote);
	_ ->
	    orphan_tables(Tabs, Node, Ns, Local, Remote)
    end;
orphan_tables([], _, _, LocalOrphans, RemoteMasters) ->
    {LocalOrphans, RemoteMasters}.

node_has_tabs([Tab | Tabs], Node, State) when Node /= node() ->
    State2 = 
	case catch update_whereabouts(Tab, Node, State) of
	    State1 = #state{} -> State1;
	    {'EXIT', R} ->  %% Tab was just deleted?
		case ?catch_val({Tab, cstruct}) of
		    {'EXIT', _} -> State; % yes
		    _ ->  erlang:error(R) 
		end
	end,
    node_has_tabs(Tabs, Node, State2);
node_has_tabs([Tab | Tabs], Node, State) ->
    user_sync_tab(Tab),
    node_has_tabs(Tabs, Node, State);
node_has_tabs([], _Node, State) ->
    State.

update_whereabouts(Tab, Node, State) ->
    Storage = val({Tab, storage_type}),
    Read = val({Tab, where_to_read}),
    LocalC = val({Tab, local_content}),
    BeingCreated = (?catch_val({Tab, create_table}) == true),
    Masters = mnesia_recover:get_master_nodes(Tab),
    ByForce = val({Tab, load_by_force}),
    GoGetIt =
	if
	    ByForce == true ->
		true;
	    Masters == [] ->
		true;
	    true ->
		lists:member(Node, Masters)
	end,
    
    dbg_out("Table ~w is loaded on ~w. s=~w, r=~w, lc=~w, f=~w, m=~w~n",
	    [Tab, Node, Storage, Read, LocalC, ByForce, GoGetIt]),
    if
	LocalC == true ->
	    %% Local contents, don't care about other node
	    State;
	BeingCreated == true ->	    
	    %% The table is currently being created
	    %% It will be handled elsewhere
	    State;
	Storage == unknown, Read == nowhere ->
	    %% No own copy, time to read remotely
	    %% if the other node is a good node
	    add_active_replica(Tab, Node),
	    case GoGetIt of
		true ->
		    set({Tab, where_to_read}, Node),
		    user_sync_tab(Tab),
		    State;
		false ->
		    State
	    end;
	Storage == unknown ->
	    %% No own copy, continue to read remotely	    
	    add_active_replica(Tab, Node),	    
	    NodeST = mnesia_lib:storage_type_at_node(Node, Tab),
	    ReadST = mnesia_lib:storage_type_at_node(Read, Tab),
	    if   %% Avoid reading from disc_only_copies
		NodeST == disc_only_copies ->
		    ignore;
		ReadST == disc_only_copies ->
		    mnesia_lib:set_remote_where_to_read(Tab);
		true ->
		    ignore
	    end,
	    user_sync_tab(Tab),
	    State;
	Read == nowhere ->
	    %% Own copy, go and get a copy of the table
	    %% if the other node is master or if there
	    %% are no master at all
	    add_active_replica(Tab, Node),
	    case GoGetIt of
		true ->
		    Worker = #net_load{table = Tab,
				       reason = {active_remote, Node}},
		    add_worker(Worker, State);
		false ->
		    State
	    end;
	true ->
	    %% We already have an own copy
	    add_active_replica(Tab, Node),
	    user_sync_tab(Tab),
	    State
    end.

initial_safe_loads() ->
    case val({schema, storage_type}) of
	ram_copies ->
	    Downs = [],
	    Tabs = val({schema, local_tables}) -- [schema],
	    LastC = fun(T) -> last_consistent_replica(T, Downs) end,
	    lists:zf(LastC, Tabs);
	
	disc_copies ->
	    Downs = mnesia_recover:get_mnesia_downs(),
	    dbg_out("mnesia_downs = ~p~n", [Downs]),
		
	    Tabs = val({schema, local_tables}) -- [schema],
	    LastC = fun(T) -> last_consistent_replica(T, Downs) end,
	    lists:zf(LastC, Tabs)
    end.
    
last_consistent_replica(Tab, Downs) ->
    Cs = val({Tab, cstruct}),
    Storage = mnesia_lib:cs_to_storage_type(node(), Cs),
    Ram = Cs#cstruct.ram_copies,
    Disc = Cs#cstruct.disc_copies,
    DiscOnly = Cs#cstruct.disc_only_copies,
    BetterCopies0 = mnesia_lib:remote_copy_holders(Cs) -- Downs,
    BetterCopies = BetterCopies0 -- Ram,
    AccessMode = Cs#cstruct.access_mode,
    Copies = mnesia_lib:copy_holders(Cs),
    Masters = mnesia_recover:get_master_nodes(Tab),
    LocalMaster0 = lists:member(node(), Masters),
    LocalContent = Cs#cstruct.local_content,
    RemoteMaster =
	if
	    Masters == [] -> false;
	    true -> not LocalMaster0
	end,
    LocalMaster =
	if
	    Masters == [] -> false;
	    true -> LocalMaster0
	end,
    if
	Copies == [node()]  ->
	    %% Only one copy holder and it is local.
	    %% It may also be a local contents table
	    {true, {Tab, local_only}};
	LocalContent == true ->
	    {true, {Tab, local_content}};
	LocalMaster == true ->
	    %% We have a local master
	    {true, {Tab, local_master}};
	RemoteMaster == true ->
	    %% Wait for remote master copy
	    false;
	Storage == ram_copies ->
	    if
		Disc == [], DiscOnly == [] ->
		    %% Nobody has copy on disc
		    {true, {Tab, ram_only}};
		true ->
		    %% Some other node has copy on disc
		    false
	    end;
	AccessMode == read_only ->
	    %% No one has been able to update the table,
	    %% i.e. all disc resident copies are equal
	    {true, {Tab, read_only}};
	BetterCopies /= [], Masters /= [node()] ->
	    %% There are better copies on other nodes
	    %% and we do not have the only master copy
	    false;
	true ->
	    {true, {Tab, initial}}
    end.

reconfigure_tables(N, [Tab |Tail]) ->
    del_active_replica(Tab, N),
    case val({Tab, where_to_read}) of
	N ->  mnesia_lib:set_remote_where_to_read(Tab);
	_ ->  ignore
    end,
    reconfigure_tables(N, Tail);
reconfigure_tables(_, []) ->
    ok.

remove_loaders([Tab| Tabs], N, Loaders) ->
    LateQ = drop_loaders(Tab, N, Loaders),
    remove_loaders(Tabs, N, LateQ);
remove_loaders([],_, LateQ) -> LateQ.

remove_early_messages([], _Node) ->
    [];
remove_early_messages([{call, {add_active_replica, [_, Node, _, _], _}, _}|R], Node) ->
    remove_early_messages(R, Node); %% Does a reply before queuing
remove_early_messages([{call, {block_table, _, From}, ReplyTo}|R], Node) 
  when node(From) == Node ->
    reply(ReplyTo, ok),  %% Remove gen:server waits..
    remove_early_messages(R, Node);
remove_early_messages([{cast, {i_have_tab, _Tab, Node}}|R], Node) ->
    remove_early_messages(R, Node);
remove_early_messages([{cast, {adopt_orphans, Node, _Tabs}}|R], Node) ->
    remove_early_messages(R, Node);
remove_early_messages([M|R],Node) ->
    [M|remove_early_messages(R,Node)].

%% Drop loader from late load queue and possibly trigger a disc_load
drop_loaders(Tab, Node, LLQ) ->
    case gb_trees:lookup(Tab,LLQ) of
	none ->
	    LLQ;
	{value, H} ->
	    %% Check if it is time to issue a disc_load request
	    case H#late_load.loaders of
		[Node] ->
		    Reason = {H#late_load.reason, last_loader_down, Node},
		    cast({disc_load, Tab, Reason});  % Ugly cast
		_ ->
		    ignore
	    end,
	    %% Drop the node from the list of loaders
	    H2 = H#late_load{loaders = H#late_load.loaders -- [Node]},
	    gb_trees:update(Tab, H2, LLQ)
    end.

add_active_replica(Tab, Node) ->
    add_active_replica(Tab, Node, val({Tab, cstruct})).

add_active_replica(Tab, Node, Cs = #cstruct{}) ->
    Storage = mnesia_lib:schema_cs_to_storage_type(Node, Cs),
    AccessMode = Cs#cstruct.access_mode,
    add_active_replica(Tab, Node, Storage, AccessMode).

%% Block table primitives

block_table(Tab) ->
    Var = {Tab, where_to_commit},
    Old = val(Var),
    New = {blocked, Old},
    set(Var, New). % where_to_commit

unblock_table(Tab) ->
    call({unblock_table, Tab}).

is_tab_blocked(W2C) when is_list(W2C) ->
    {false, W2C};
is_tab_blocked({blocked, W2C}) when is_list(W2C) ->
    {true, W2C}.

mark_blocked_tab(true, Value) -> 
    {blocked, Value};
mark_blocked_tab(false, Value) -> 
    Value.

%%

add_active_replica(Tab, Node, Storage, AccessMode) ->
    Var = {Tab, where_to_commit},
    {Blocked, Old} = is_tab_blocked(val(Var)),
    Del = lists:keydelete(Node, 1, Old),
    case AccessMode of
	read_write ->
	    New = lists:sort([{Node, Storage} | Del]),
	    set(Var, mark_blocked_tab(Blocked, New)), % where_to_commit
	    mnesia_lib:add_lsort({Tab, where_to_write}, Node);
	read_only ->
	    set(Var, mark_blocked_tab(Blocked, Del)),
	    mnesia_lib:del({Tab, where_to_write}, Node)
    end,

    update_where_to_wlock(Tab),
    add({Tab, active_replicas}, Node).

del_active_replica(Tab, Node) ->
    Var = {Tab, where_to_commit},
    {Blocked, Old} = is_tab_blocked(val(Var)),
    Del = lists:keydelete(Node, 1, Old),
    New = lists:sort(Del),
    set(Var, mark_blocked_tab(Blocked, New)),      % where_to_commit
    mnesia_lib:del({Tab, active_replicas}, Node),
    mnesia_lib:del({Tab, where_to_write}, Node),
    update_where_to_wlock(Tab).

change_table_access_mode(Cs) ->
    W = fun() -> 
		Tab = Cs#cstruct.name,
		lists:foreach(fun(N) -> add_active_replica(Tab, N, Cs) end,
			      val({Tab, active_replicas}))
	end,
    update(W).

change_table_majority(Cs) ->
    W = fun() ->
		Tab = Cs#cstruct.name,
		set({Tab, majority}, Cs#cstruct.majority),
		update_where_to_wlock(Tab)
	end,
    update(W).

update_where_to_wlock(Tab) ->
    WNodes = val({Tab, where_to_write}),
    Majority = case catch val({Tab, majority}) of
		   true -> true;
		   _    -> false
	       end,
    set({Tab, where_to_wlock}, {WNodes, Majority}).

%% node To now has tab loaded, but this must be undone
%% This code is rpc:call'ed from the tab_copier process
%% when it has *not* released it's table lock
unannounce_add_table_copy(Tab, To) ->
    catch del_active_replica(Tab, To),
    case catch val({Tab , where_to_read}) of
	To -> 
	    mnesia_lib:set_remote_where_to_read(Tab);
	_ ->
	    ignore
    end.

user_sync_tab(Tab) ->
    case val(debug) of
	trace ->
	    mnesia_subscr:subscribe(whereis(mnesia_event), {table, Tab});
	_ ->
	    ignore
    end,
	
    case erase({sync_tab, Tab}) of
	undefined ->
	    ok;
	Pids ->
	    lists:foreach(fun(Pid) -> sync_reply(Pid, Tab) end, Pids)
    end.

i_have_tab(Tab) ->
    case val({Tab, local_content}) of
	true ->
	    mnesia_lib:set_local_content_whereabouts(Tab);
	false ->
	    set({Tab, where_to_read}, node())
    end,
    add_active_replica(Tab, node()).

sync_and_block_table_whereabouts(Tab, ToNode, RemoteS, AccessMode) when Tab /= schema ->
    Current = val({current, db_nodes}),
    Ns = 
	case lists:member(ToNode, Current) of
	    true -> Current -- [ToNode];
	    false -> Current
	end,   
    remote_call(ToNode, block_table, [Tab]),
    [remote_call(Node, add_active_replica, [Tab, ToNode, RemoteS, AccessMode]) ||
	Node <- [ToNode | Ns]],
    ok.

sync_del_table_copy_whereabouts(Tab, ToNode) when Tab /= schema ->
    Current = val({current, db_nodes}),
    Ns =
	case lists:member(ToNode, Current) of
	    true -> Current;
	    false -> [ToNode | Current]
	end,
    Args = [Tab, ToNode],
    [remote_call(Node, unannounce_add_table_copy, Args) || Node <- Ns],
    ok.

get_info(Timeout) ->
    case whereis(?SERVER_NAME) of
	undefined ->
	    {timeout, Timeout};
	Pid ->
	    Pid ! {self(), get_state},
	    receive
		{?SERVER_NAME, State = #state{loader_queue=LQ,late_loader_queue=LLQ}} ->
		    {info,State#state{loader_queue=gb_trees:to_list(LQ),
				      late_loader_queue=gb_trees:to_list(LLQ)}}
	    after Timeout ->
		    {timeout, Timeout}
	    end
    end.

get_workers(Timeout) ->
    case whereis(?SERVER_NAME) of
	undefined ->
	    {timeout, Timeout};
	Pid ->
	    Pid ! {self(), get_state},
	    receive
		{?SERVER_NAME, State = #state{}} ->
		    {workers, get_loaders(State), get_senders(State), State#state.dumper_pid}
	    after Timeout ->
		    {timeout, Timeout}
	    end
    end.
    
info() ->
    Tabs = mnesia_lib:local_active_tables(),
    io:format( "---> Active tables <--- ~n", []),
    info(Tabs).

info([Tab | Tail]) ->
    case val({Tab, storage_type}) of
	disc_only_copies ->
	    info_format(Tab, 
			dets:info(Tab, size), 
			dets:info(Tab, file_size),
			"bytes on disc");
	_ ->
	    info_format(Tab, 
			?ets_info(Tab, size),
			?ets_info(Tab, memory),
			"words of mem")
    end,
    info(Tail);
info([]) -> ok.


info_format(Tab, Size, Mem, Media) ->
    StrT = mnesia_lib:pad_name(atom_to_list(Tab), 15, []),
    StrS = mnesia_lib:pad_name(integer_to_list(Size), 8, []),
    StrM = mnesia_lib:pad_name(integer_to_list(Mem), 8, []),
    io:format("~s: with ~s records occupying ~s ~s~n",
	      [StrT, StrS, StrM, Media]).

%% Handle early arrived messages
handle_early_msgs([Msg | Msgs], State) ->
    %% The messages are in reverse order
    case handle_early_msg(Msg, State) of
%%         {stop, Reason, Reply, State2} ->  % Will not happen according to dialyzer
%% 	    {stop, Reason, Reply, State2};
        {stop, Reason, State2} ->
	    {stop, Reason, State2};
	{noreply, State2} ->
	    handle_early_msgs(Msgs, State2);
 	{reply, Reply, State2} ->
	    {call, _Call, From} = Msg,
	    reply(From, Reply),
 	    handle_early_msgs(Msgs, State2)
    end;
handle_early_msgs([], State) ->
    noreply(State).

handle_early_msg({call, Msg, From}, State) ->
    handle_call(Msg, From, State);
handle_early_msg({cast, Msg}, State) ->
    handle_cast(Msg, State);
handle_early_msg({info, Msg}, State) ->
    handle_info(Msg, State).
    
noreply(State) ->
    {noreply, State}.

reply(undefined, Reply) ->
    Reply;
reply(ReplyTo, Reply) ->
    gen_server:reply(ReplyTo, Reply),
    Reply.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Worker management

%% Returns new State
add_worker(Worker = #dump_log{}, State) ->
    InitBy = Worker#dump_log.initiated_by,
    Queue = State#state.dumper_queue,
    Status =
        case lists:keymember(InitBy, #dump_log.initiated_by, Queue) of
            true when Worker#dump_log.opt_reply_to == undefined ->
                %% The same threshold has been exceeded again,
                %% before we have had the possibility to
                %% process the older one.
                DetectedBy = {dump_log, InitBy},
                Event = {mnesia_overload, DetectedBy},
                mnesia_lib:report_system_event(Event),
                true;
            _ ->
                false
        end,
    mnesia_recover:log_dump_overload(Status),
    Queue2 = Queue ++ [Worker],
    State2 = State#state{dumper_queue = Queue2},
    opt_start_worker(State2);
add_worker(Worker = #schema_commit_lock{}, State) ->
    Queue = State#state.dumper_queue,
    Queue2 = Queue ++ [Worker],
    State2 = State#state{dumper_queue = Queue2},
    opt_start_worker(State2);
add_worker(Worker = #net_load{}, State) ->
    opt_start_worker(add_loader(Worker#net_load.table,Worker,State));
add_worker(Worker = #send_table{}, State) ->
    Queue = State#state.sender_queue,
    State2 = State#state{sender_queue = Queue ++ [Worker]},
    opt_start_worker(State2);
add_worker(Worker = #disc_load{}, State) ->
    opt_start_worker(add_loader(Worker#disc_load.table,Worker,State));
% Block controller should be used for upgrading mnesia.
add_worker(Worker = #block_controller{}, State) -> 
    Queue = State#state.dumper_queue,
    Queue2 = [Worker | Queue],
    State2 = State#state{dumper_queue = Queue2},
    opt_start_worker(State2).

add_loader(Tab,Worker,State = #state{loader_queue=LQ0}) ->
    case gb_trees:is_defined(Tab, LQ0) of
	true -> State;
	false -> 
	    LQ=gb_trees:insert(Tab, Worker, LQ0),
	    State#state{loader_queue=LQ}
    end.

%% Optionally start a worker
%% 
%% Dumpers and loaders may run simultaneously
%% but neither of them may run during schema commit.
%% Loaders may not start if a schema commit is enqueued.
opt_start_worker(State) when State#state.is_stopping == true ->
    State;
opt_start_worker(State) ->
    %% Prioritize dumper and schema commit
    %% by checking them first
    case State#state.dumper_queue of
	[Worker | _Rest] when State#state.dumper_pid == undefined ->
	    %% Great, a worker in queue and neither
	    %% a schema transaction is being
	    %% committed and nor a dumper is running
		    
	    %% Start worker but keep him in the queue
	    if
		is_record(Worker, schema_commit_lock) ->
		    ReplyTo = Worker#schema_commit_lock.owner,
		    reply(ReplyTo, granted),
		    {Owner, _Tag} = ReplyTo,
		    opt_start_loader(State#state{dumper_pid = Owner});
		
		is_record(Worker, dump_log) ->
		    Pid = spawn_link(?MODULE, dump_and_reply, [self(), Worker]),
		    State2 = State#state{dumper_pid = Pid},

		    %% If the worker was a dumper we may
		    %% possibly be able to start a loader
		    %% or sender
		    State3 = opt_start_sender(State2),
		    opt_start_loader(State3);
		
		is_record(Worker, block_controller) ->
		    case {get_senders(State), get_loaders(State)} of
			{[], []} ->
			    ReplyTo = Worker#block_controller.owner,
			    reply(ReplyTo, granted),
			    {Owner, _Tag} = ReplyTo,
			    State#state{dumper_pid = Owner};
			_ ->
			    State
		    end
	    end;
	_ ->
	    %% Bad luck, try with a loader or sender instead 
	    State2 = opt_start_sender(State),
	    opt_start_loader(State2)
    end.

opt_start_sender(State) ->
    case State#state.sender_queue of
	[]->   State; 	    %% No need
	SenderQ -> 
	    {NewS,Kept} = opt_start_sender2(SenderQ, get_senders(State), 
					    [], get_loaders(State)),
	    State#state{sender_pid = NewS, sender_queue = Kept}
    end.

opt_start_sender2([], Pids,Kept, _) -> {Pids,Kept};
opt_start_sender2([Sender|R], Pids, Kept, LoaderQ) ->
    Tab = Sender#send_table.table,
    Active = val({Tab, active_replicas}),
    IgotIt = lists:member(node(), Active),    
    IsLoading = lists:any(fun({_Pid,Loader}) -> 
				  Tab == element(#net_load.table, Loader)
			  end, LoaderQ),
    if 
	IgotIt, IsLoading  ->
	    %% I'm currently finishing loading the table let him wait
	    opt_start_sender2(R,Pids, [Sender|Kept], LoaderQ);
	IgotIt ->
	    %% Start worker but keep him in the queue
	    Pid = spawn_link(?MODULE, send_and_reply,[self(), Sender]),
	    opt_start_sender2(R,[{Pid,Sender}|Pids],Kept,LoaderQ);
	true ->
	    verbose("Send table failed ~p not active on this node ~n", [Tab]),
	    Sender#send_table.receiver_pid ! {copier_done, node()},
	    opt_start_sender2(R,Pids, Kept, LoaderQ)
    end.

opt_start_loader(State = #state{loader_queue = LoaderQ}) ->
    Current = get_loaders(State),
    Max = max_loaders(),
    case gb_trees:is_empty(LoaderQ) of
	true -> 
	    State;
	_ when length(Current) >= Max -> 
	    State;
	false -> 
	    SchemaQueue = State#state.dumper_queue,
	    case lists:keymember(schema_commit_lock, 1, SchemaQueue) of
		false ->
		    case pick_next(LoaderQ) of
			{none,Rest} ->
			    State#state{loader_queue=Rest};
			{Worker,Rest} ->
			    case already_loading(Worker, get_loaders(State)) of
				true ->
				    opt_start_loader(State#state{loader_queue = Rest});
				false ->
				    %% Start worker but keep him in the queue
				    Pid = load_and_reply(self(), Worker),
				    State#state{loader_pid=[{Pid,Worker}|get_loaders(State)],
						loader_queue = Rest}
			    end
		    end;
		true ->
		    %% Bad luck, we must wait for the schema commit
		    State
	    end
    end.

already_loading(#net_load{table=Tab},Loaders) ->
    already_loading2(Tab,Loaders);
already_loading(#disc_load{table=Tab},Loaders) ->
    already_loading2(Tab,Loaders).

already_loading2(Tab, [{_,#net_load{table=Tab}}|_]) -> true;
already_loading2(Tab, [{_,#disc_load{table=Tab}}|_]) -> true;
already_loading2(Tab, [_|Rest]) -> already_loading2(Tab,Rest);     
already_loading2(_,[]) -> false.

start_remote_sender(Node, Tab, Receiver, Storage) ->
    Msg = #send_table{table = Tab,
		      receiver_pid = Receiver,
		      remote_storage = Storage},
    gen_server:cast({?SERVER_NAME, Node}, Msg).

dump_and_reply(ReplyTo, Worker) ->
    %% No trap_exit, die intentionally instead
    Res = mnesia_dumper:opt_dump_log(Worker#dump_log.initiated_by),
    ReplyTo ! #dumper_done{worker_pid = self(),
			   worker_res = Res},
    unlink(ReplyTo),
    exit(normal).

send_and_reply(ReplyTo, Worker) ->
    %% No trap_exit, die intentionally instead
    Res = mnesia_loader:send_table(Worker#send_table.receiver_pid,
				   Worker#send_table.table,
				   Worker#send_table.remote_storage),
    ReplyTo ! #sender_done{worker_pid = self(),
			   worker_res = Res},
    unlink(ReplyTo),
    exit(normal).

load_and_reply(ReplyTo, Worker) ->
    Load = load_table_fun(Worker),
    SendAndReply = 
	fun() -> 
		process_flag(trap_exit, true),
		Done = Load(),
		ReplyTo ! Done#loader_done{worker_pid = self()},
		unlink(ReplyTo),
		exit(normal)
	end,
    spawn_link(SendAndReply).

%% Now it is time to load the table
%% but first we must check if it still is neccessary
load_table_fun(#net_load{cstruct=Cs, table=Tab, reason=Reason, opt_reply_to=ReplyTo}) ->
    LocalC = val({Tab, local_content}),
    AccessMode = val({Tab, access_mode}),
    ReadNode = val({Tab, where_to_read}),
    Active = filter_active(Tab),
    Done = #loader_done{is_loaded = true,
			table_name = Tab,
			needs_announce = false,
			needs_sync = false,
			needs_reply = (ReplyTo /= undefined),
			reply_to = ReplyTo,
			reply = {loaded, ok}
		       },
    if
	ReadNode == node() ->
	    %% Already loaded locally
	    fun() -> Done end;
	LocalC == true ->
	    fun() ->
		    Res = mnesia_loader:disc_load_table(Tab, load_local_content),
		    Done#loader_done{reply = Res, needs_announce = true, needs_sync = true}
	    end;
	AccessMode == read_only, Reason /= {dumper,add_table_copy} ->
	    fun() -> disc_load_table(Tab, Reason, ReplyTo) end;
	true ->
	    fun() ->
		    %% Either we cannot read the table yet
		    %% or someone is moving a replica between
		    %% two nodes
		    Res = mnesia_loader:net_load_table(Tab, Reason, Active, Cs),
		    case Res of
			{loaded, ok} ->
			    Done#loader_done{needs_sync = true,
					     reply = Res};
			{not_loaded, _} ->
			    Done#loader_done{is_loaded = false,
					     reply = Res}
		    end
	    end
    end;
load_table_fun(#disc_load{table=Tab, reason=Reason, opt_reply_to=ReplyTo}) ->
    ReadNode = val({Tab, where_to_read}),
    Active = filter_active(Tab),
    Done = #loader_done{is_loaded = true,
			table_name = Tab,
			needs_announce = false,
			needs_sync = false,
			needs_reply = false
		       },
    if
	Active == [], ReadNode == nowhere ->
	    %% Not loaded anywhere, lets load it from disc
	    fun() -> disc_load_table(Tab, Reason, ReplyTo) end;
	ReadNode == nowhere ->
	    %% Already loaded on other node, lets get it
	    Cs = val({Tab, cstruct}),
	    fun() -> 
		    case mnesia_loader:net_load_table(Tab, Reason, Active, Cs) of
			{loaded, ok} ->
			    Done#loader_done{needs_sync = true};
			{not_loaded, storage_unknown} ->
			    Done#loader_done{is_loaded = false};
			{not_loaded, ErrReason} ->
			    Done#loader_done{is_loaded = false,
					     reply = {not_loaded,ErrReason}}
		    end
	    end;
	true ->
	    %% Already readable, do not worry be happy
	    fun() -> Done end
    end.

disc_load_table(Tab, Reason, ReplyTo) ->
    Done = #loader_done{is_loaded = true,
			table_name = Tab,
			needs_announce = false,
			needs_sync = false,
			needs_reply = ReplyTo /= undefined,
			reply_to = ReplyTo,
			reply = {loaded, ok}
		       },
    Res = mnesia_loader:disc_load_table(Tab, Reason),
    if
	Res == {loaded, ok} ->
	    Done#loader_done{needs_announce = true,
			     needs_sync = true,
			     reply = Res};
	ReplyTo /= undefined ->
	    Done#loader_done{is_loaded = false,
			     reply = Res};
	true ->
	    fatal("Cannot load table ~p from disc: ~p~n", [Tab, Res])
    end.

filter_active(Tab) ->
    ByForce = val({Tab, load_by_force}),
    Active  = val({Tab, active_replicas}),
    Masters = mnesia_recover:get_master_nodes(Tab),
    Ns = do_filter_active(ByForce, Active, Masters),
    %% Reorder the so that we load from fastest first 
    LS = ?catch_val({Tab, storage_type}),
    DOC = val({Tab, disc_only_copies}),
    {Good,Worse} = 
	case LS of
	    disc_only_copies ->
		G = mnesia_lib:intersect(Ns, DOC),
		{G,Ns--G};
	    _ ->
		G = Ns -- DOC,
		{G,Ns--G}
	end,
    %% Pick a random node of the fastest
    Len = length(Good),
    if 
	Len > 0 ->
	    R = erlang:phash(node(), Len+1),
	    random(R-1,Good,Worse);
	true  ->
	    Worse
    end.

random(N, [H|R], Acc) when N > 0 ->
    random(N-1,R, [H|Acc]);
random(0, L, Acc) ->
    L ++ Acc.

do_filter_active(true, Active, _Masters) ->
    Active;
do_filter_active(false, Active, []) ->
    Active;
do_filter_active(false, Active, Masters) ->
    mnesia_lib:intersect(Active, Masters).