%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 1996-2016. All Rights Reserved.
%%
%% Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
%% You may obtain a copy of the License at
%%
%% http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.
%%
%% %CopyrightEnd%
%%
%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%
%% This module administers three kinds of log files:
%%
%% 1 The transaction log
%% mnesia_tm appends to the log (via mnesia_log) at the
%% end of each transaction (or dirty write) and
%% mnesia_dumper reads the log and performs the ops in
%% the dat files. The dump_log is done at startup and
%% at intervals controlled by the user.
%%
%% 2 The mnesia_down log
%% mnesia_tm appends to the log (via mnesia_log) when it
%% realizes that mnesia goes up or down on another node.
%% mnesia_init reads the log (via mnesia_log) at startup.
%%
%% 3 The backup log
%% mnesia_schema produces one tiny log when the schema is
%% initially created. mnesia_schema also reads the log
%% when the user wants tables (possibly incl the schema)
%% to be restored. mnesia_log appends to the log when the
%% user wants to produce a real backup.
%%
%% The actual access to the backup media is performed via the
%% mnesia_backup module for both read and write. mnesia_backup
%% uses the disk_log (*), BUT the user may write an own module
%% with the same interface as mnesia_backup and configure
%% Mnesia so the alternate module performs the actual accesses
%% to the backup media. This means that the user may put the
%% backup on medias that Mnesia does not know about possibly on
%% hosts where Erlang is not running.
%%
%% All these logs have to some extent a common structure.
%% They are all using the disk_log module (*) for the basic
%% file structure. The disk_log has a repair feature that
%% can be used to skip erroneous log records if one comes to
%% the conclusion that it is more important to reuse some
%% of the log records than the risque of obtaining inconsistent
%% data. If the data becomes inconsistent it is solely up to the
%% application to make it consistent again. The automatic
%% reparation of the disk_log is very powerful, but use it
%% with extreme care.
%%
%% First in all Mnesia's log file is a mnesia log header.
%% It contains a list with a log_header record as single
%% element. The structure of the log_header may never be
%% changed since it may be written to very old backup files.
%% By holding this record definition stable we can be
%% able to comprahend backups from timepoint 0. It also
%% allows us to use the backup format as an interchange
%% format between Mnesia releases.
%%
%% An op-list is a list of tuples with arity 3. Each tuple
%% has this structure: {Oid, Recs, Op} where Oid is the tuple
%% {Tab, Key}, Recs is a (possibly empty) list of records and
%% Op is an atom.
%%
%% The log file structure for the transaction log is as follows.
%%
%% After the mnesia log section follows an extended record section
%% containing op-lists. There are several values that Op may
%% have, such as write, delete, update_counter, delete_object,
%% and replace. There is no special end of section marker.
%%
%% +-----------------+
%% | mnesia log head |
%% +-----------------+
%% | extended record |
%% | section |
%% +-----------------+
%%
%% The log file structure for the mnesia_down log is as follows.
%%
%% After the mnesia log section follows a mnesia_down section
%% containg lists with yoyo records as single element.
%%
%% +-----------------+
%% | mnesia log head |
%% +-----------------+
%% | mnesia_down |
%% | section |
%% +-----------------+
%%
%% The log file structure for the backup log is as follows.
%%
%% After the mnesia log section follows a schema section
%% containing record lists. A record list is a list of tuples
%% where {schema, Tab} is interpreted as a delete_table(Tab) and
%% {schema, Tab, CreateList} are interpreted as create_table.
%%
%% The record section also contains record lists. In this section
%% {Tab, Key} is interpreted as delete({Tab, Key}) and other tuples
%% as write(Tuple). There is no special end of section marker.
%%
%% +-----------------+
%% | mnesia log head |
%% +-----------------+
%% | schema section |
%% +-----------------+
%% | record section |
%% +-----------------+
%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-module(mnesia_log).
-export([
append/2,
backup/1,
backup/2,
backup_checkpoint/2,
backup_checkpoint/3,
backup_log_header/0,
backup_master/2,
chunk_decision_log/1,
chunk_decision_tab/1,
chunk_log/1,
chunk_log/2,
close_decision_log/0,
close_decision_tab/0,
close_log/1,
unsafe_close_log/1,
confirm_log_dump/1,
confirm_decision_log_dump/0,
previous_log_file/0,
previous_decision_log_file/0,
latest_log_file/0,
decision_log_version/0,
decision_log_file/0,
decision_tab_file/0,
decision_tab_version/0,
dcl_version/0,
dcd_version/0,
ets2dcd/1,
ets2dcd/2,
dcd2ets/1,
dcd2ets/2,
init/0,
init_log_dump/0,
log/1,
slog/1,
log_decision/1,
log_files/0,
open_decision_log/0,
trans_log_header/0,
open_decision_tab/0,
dcl_log_header/0,
dcd_log_header/0,
open_log/4,
open_log/6,
prepare_decision_log_dump/0,
prepare_log_dump/1,
save_decision_tab/1,
purge_all_logs/0,
purge_some_logs/0,
stop/0,
tab_copier/3,
version/0,
view/0,
view/1,
write_trans_log_header/0
]).
-compile({no_auto_import,[error/2]}).
-include("mnesia.hrl").
-import(mnesia_lib, [val/1, dir/1]).
-import(mnesia_lib, [exists/1, fatal/2, error/2, dbg_out/2]).
trans_log_header() -> log_header(trans_log, version()).
backup_log_header() -> log_header(backup_log, "1.2").
decision_log_header() -> log_header(decision_log, decision_log_version()).
decision_tab_header() -> log_header(decision_tab, decision_tab_version()).
dcl_log_header() -> log_header(dcl_log, dcl_version()).
dcd_log_header() -> log_header(dcd_log, dcd_version()).
log_header(Kind, Version) ->
#log_header{log_version=Version,
log_kind=Kind,
mnesia_version=mnesia:system_info(version),
node=node(),
now=erlang:timestamp()}.
version() -> "4.3".
decision_log_version() -> "3.0".
decision_tab_version() -> "1.0".
dcl_version() -> "1.0".
dcd_version() -> "1.0".
append(Log, Bin) when is_binary(Bin) ->
disk_log:balog(Log, Bin);
append(Log, Term) ->
disk_log:alog(Log, Term).
%% Synced append
sappend(Log, Bin) when is_binary(Bin) ->
ok = disk_log:blog(Log, Bin);
sappend(Log, Term) ->
ok = disk_log:log(Log, Term).
%% Write commit records to the latest_log
log(C) when C#commit.disc_copies == [],
C#commit.disc_only_copies == [],
C#commit.schema_ops == [] ->
ignore;
log(C) ->
case mnesia_monitor:use_dir() of
true ->
if
is_record(C, commit) ->
C2 = C#commit{ram_copies = [], snmp = []},
append(latest_log, C2);
true ->
%% Either a commit record as binary
%% or some decision related info
append(latest_log, C)
end,
mnesia_dumper:incr_log_writes();
false ->
ignore
end.
%% Synced
slog(C) when C#commit.disc_copies == [],
C#commit.disc_only_copies == [],
C#commit.schema_ops == [] ->
ignore;
slog(C) ->
case mnesia_monitor:use_dir() of
true ->
if
is_record(C, commit) ->
C2 = C#commit{ram_copies = [], snmp = []},
sappend(latest_log, C2);
true ->
%% Either a commit record as binary
%% or some decision related info
sappend(latest_log, C)
end,
mnesia_dumper:incr_log_writes();
false ->
ignore
end.
%% Stuff related to the file LOG
%% Returns a list of logfiles. The oldest is first.
log_files() -> [previous_log_file(),
latest_log_file(),
decision_tab_file()
].
latest_log_file() -> dir(latest_log_name()).
previous_log_file() -> dir("PREVIOUS.LOG").
decision_log_file() -> dir(decision_log_name()).
decision_tab_file() -> dir(decision_tab_name()).
previous_decision_log_file() -> dir("PDECISION.LOG").
latest_log_name() -> "LATEST.LOG".
decision_log_name() -> "DECISION.LOG".
decision_tab_name() -> "DECISION_TAB.LOG".
init() ->
case mnesia_monitor:use_dir() of
true ->
Prev = previous_log_file(),
verify_no_exists(Prev),
Latest = latest_log_file(),
verify_no_exists(Latest),
Header = trans_log_header(),
open_log(latest_log, Header, Latest);
false ->
ok
end.
verify_no_exists(Fname) ->
case exists(Fname) of
false ->
ok;
true ->
fatal("Log file exists: ~p~n", [Fname])
end.
open_log(Name, Header, Fname) ->
Exists = exists(Fname),
open_log(Name, Header, Fname, Exists).
open_log(Name, Header, Fname, Exists) ->
Repair = mnesia_monitor:get_env(auto_repair),
open_log(Name, Header, Fname, Exists, Repair).
open_log(Name, Header, Fname, Exists, Repair) ->
case Name == previous_log of
true ->
open_log(Name, Header, Fname, Exists, Repair, read_only);
false ->
open_log(Name, Header, Fname, Exists, Repair, read_write)
end.
open_log(Name, Header, Fname, Exists, Repair, Mode) ->
Args = [{file, Fname}, {name, Name}, {repair, Repair}, {mode, Mode}],
%% io:format("~p:open_log: ~p ~p~n", [?MODULE, Name, Fname]),
case mnesia_monitor:open_log(Args) of
{ok, Log} when Exists == true ->
Log;
{ok, Log} ->
write_header(Log, Header),
Log;
{repaired, Log, _, {badbytes, 0}} when Exists == true ->
Log;
{repaired, Log, _, {badbytes, 0}} ->
write_header(Log, Header),
Log;
{repaired, Log, _Recover, BadBytes} ->
mnesia_lib:important("Data may be missing, log ~p repaired: Lost ~p bytes~n",
[Fname, BadBytes]),
Log;
{error, Reason = {file_error, _Fname, emfile}} ->
fatal("Cannot open log file ~p: ~p~n", [Fname, Reason]);
{error, Reason} when Repair == true ->
file:delete(Fname),
mnesia_lib:important("Data may be missing, Corrupt logfile deleted: ~p, ~p ~n",
[Fname, Reason]),
%% Create a new
open_log(Name, Header, Fname, false, false, read_write);
{error, Reason} ->
fatal("Cannot open log file ~p: ~p~n", [Fname, Reason])
end.
write_header(Log, Header) ->
append(Log, Header).
write_trans_log_header() ->
write_header(latest_log, trans_log_header()).
stop() ->
case mnesia_monitor:use_dir() of
true ->
close_log(latest_log);
false ->
ok
end.
close_log(Log) ->
%% io:format("mnesia_log:close_log ~p~n", [Log]),
%% io:format("mnesia_log:close_log ~p~n", [Log]),
case disk_log:sync(Log) of
ok -> ok;
{error, {read_only_mode, Log}} ->
ok;
{error, Reason} ->
mnesia_lib:important("Failed syncing ~p to_disk reason ~p ~n",
[Log, Reason])
end,
mnesia_monitor:close_log(Log).
unsafe_close_log(Log) ->
%% io:format("mnesia_log:close_log ~p~n", [Log]),
mnesia_monitor:unsafe_close_log(Log).
purge_some_logs() ->
mnesia_monitor:unsafe_close_log(latest_log),
_ = file:delete(latest_log_file()),
_ = file:delete(decision_tab_file()),
ok.
purge_all_logs() ->
_ = file:delete(previous_log_file()),
_ = file:delete(latest_log_file()),
_ = file:delete(decision_tab_file()),
ok.
%% Prepare dump by renaming the open logfile if possible
%% Returns a tuple on the following format: {Res, OpenLog}
%% where OpenLog is the file descriptor to log file, ready for append
%% and Res is one of the following: already_dumped, needs_dump or {error, Reason}
prepare_log_dump(InitBy) ->
Diff = mnesia_dumper:get_log_writes() -
mnesia_lib:read_counter(trans_log_writes_prev),
if
Diff == 0, InitBy /= startup ->
already_dumped;
true ->
case mnesia_monitor:use_dir() of
true ->
Prev = previous_log_file(),
prepare_prev(Diff, InitBy, Prev, exists(Prev));
false ->
already_dumped
end
end.
prepare_prev(Diff, _, _, true) ->
{needs_dump, Diff};
prepare_prev(Diff, startup, Prev, false) ->
Latest = latest_log_file(),
case exists(Latest) of
true ->
case file:rename(Latest, Prev) of
ok ->
{needs_dump, Diff};
{error, Reason} ->
{error, Reason}
end;
false ->
already_dumped
end;
prepare_prev(Diff, _InitBy, Prev, false) ->
Head = trans_log_header(),
case mnesia_monitor:reopen_log(latest_log, Prev, Head) of
ok ->
{needs_dump, Diff};
{error, Reason} ->
Latest = latest_log_file(),
{error, {"Cannot rename log file",
[Latest, Prev, Reason]}}
end.
%% Init dump and return PrevLogFileDesc or exit.
init_log_dump() ->
Fname = previous_log_file(),
open_log(previous_log, trans_log_header(), Fname),
start.
chunk_log(Cont) ->
chunk_log(previous_log, Cont).
chunk_log(_Log, eof) ->
eof;
chunk_log(Log, Cont) ->
case disk_log:chunk(Log, Cont) of
{error, Reason} ->
fatal("Possibly truncated ~p file: ~p~n",
[Log, Reason]);
{C2, Chunk, _BadBytes} ->
%% Read_only case, should we warn about the bad log file?
%% BUGBUG Should we crash if Repair == false ??
%% We got to check this !!
mnesia_lib:important("~p repaired, lost ~p bad bytes~n", [Log, _BadBytes]),
{C2, Chunk};
Other ->
Other
end.
%% Confirms the dump by closing prev log and delete the file
confirm_log_dump(Updates) ->
case mnesia_monitor:close_log(previous_log) of
ok ->
file:delete(previous_log_file()),
mnesia_lib:incr_counter(trans_log_writes_prev, Updates),
dumped;
{error, Reason} ->
{error, Reason}
end.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Decision log
open_decision_log() ->
Latest = decision_log_file(),
open_log(decision_log, decision_log_header(), Latest),
start.
prepare_decision_log_dump() ->
Prev = previous_decision_log_file(),
prepare_decision_log_dump(exists(Prev), Prev).
prepare_decision_log_dump(false, Prev) ->
Head = decision_log_header(),
case mnesia_monitor:reopen_log(decision_log, Prev, Head) of
ok ->
prepare_decision_log_dump(true, Prev);
{error, Reason} ->
fatal("Cannot rename decision log file ~p -> ~p: ~p~n",
[decision_log_file(), Prev, Reason])
end;
prepare_decision_log_dump(true, Prev) ->
open_log(previous_decision_log, decision_log_header(), Prev),
start.
chunk_decision_log(Cont) ->
%% dbg_out("chunk log ~p~n", [Cont]),
chunk_log(previous_decision_log, Cont).
%% Confirms dump of the decision log
confirm_decision_log_dump() ->
case mnesia_monitor:close_log(previous_decision_log) of
ok ->
file:delete(previous_decision_log_file());
{error, Reason} ->
fatal("Cannot confirm decision log dump: ~p~n",
[Reason])
end.
save_decision_tab(Decisions) ->
Log = decision_tab,
Tmp = mnesia_lib:dir("DECISION_TAB.TMP"),
file:delete(Tmp),
open_log(Log, decision_tab_header(), Tmp),
append(Log, Decisions),
close_log(Log),
TabFile = decision_tab_file(),
ok = file:rename(Tmp, TabFile).
open_decision_tab() ->
TabFile = decision_tab_file(),
open_log(decision_tab, decision_tab_header(), TabFile),
start.
close_decision_tab() ->
close_log(decision_tab).
chunk_decision_tab(Cont) ->
%% dbg_out("chunk tab ~p~n", [Cont]),
chunk_log(decision_tab, Cont).
close_decision_log() ->
close_log(decision_log).
log_decision(Decision) ->
append(decision_log, Decision).
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Debug functions
view() ->
lists:foreach(fun(F) -> view(F) end, log_files()).
view(File) ->
mnesia_lib:show("***** ~p ***** ~n", [File]),
case exists(File) of
false ->
nolog;
true ->
N = view_only,
Args = [{file, File}, {name, N}, {mode, read_only}],
case disk_log:open(Args) of
{ok, N} ->
view_file(start, N);
{repaired, _, _, _} ->
view_file(start, N);
{error, Reason} ->
error("Cannot open log ~p: ~p~n", [File, Reason])
end
end.
view_file(C, Log) ->
case disk_log:chunk(Log, C) of
{error, Reason} ->
error("** Possibly truncated FILE ~p~n", [Reason]),
error;
eof ->
disk_log:close(Log),
eof;
{C2, Terms, _BadBytes} ->
dbg_out("Lost ~p bytes in ~p ~n", [_BadBytes, Log]),
lists:foreach(fun(X) -> mnesia_lib:show("~p~n", [X]) end,
Terms),
view_file(C2, Log);
{C2, Terms} ->
lists:foreach(fun(X) -> mnesia_lib:show("~p~n", [X]) end,
Terms),
view_file(C2, Log)
end.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Backup
-record(backup_args, {name, module, opaque, scope, prev_name, tables, cookie}).
backup(Opaque) ->
backup(Opaque, []).
backup(Opaque, Mod) when is_atom(Mod) ->
backup(Opaque, [{module, Mod}]);
backup(Opaque, Args) when is_list(Args) ->
%% Backup all tables with max redundancy
CpArgs = [{ram_overrides_dump, false}, {max, val({schema, tables})}],
case mnesia_checkpoint:activate(CpArgs) of
{ok, Name, _Nodes} ->
Res = backup_checkpoint(Name, Opaque, Args),
mnesia_checkpoint:deactivate(Name),
Res;
{error, Reason} ->
{error, Reason}
end.
backup_checkpoint(Name, Opaque) ->
backup_checkpoint(Name, Opaque, []).
backup_checkpoint(Name, Opaque, Mod) when is_atom(Mod) ->
backup_checkpoint(Name, Opaque, [{module, Mod}]);
backup_checkpoint(Name, Opaque, Args) when is_list(Args) ->
DefaultMod = mnesia_monitor:get_env(backup_module),
B = #backup_args{name = Name,
module = DefaultMod,
opaque = Opaque,
scope = global,
tables = all,
prev_name = Name},
case check_backup_args(Args, B) of
{ok, B2} ->
%% Decentralized backup
%% Incremental
Self = self(),
Pid = spawn_link(?MODULE, backup_master, [Self, B2]),
receive
{Pid, Self, Res} -> Res
end;
{error, Reason} ->
{error, Reason}
end.
check_backup_args([Arg | Tail], B) ->
try check_backup_arg_type(Arg, B) of
B2 ->
check_backup_args(Tail, B2)
catch error:_ ->
{error, {badarg, Arg}}
end;
check_backup_args([], B) ->
{ok, B}.
check_backup_arg_type(Arg, B) ->
case Arg of
{scope, global} ->
B#backup_args{scope = global};
{scope, local} ->
B#backup_args{scope = local};
{module, Mod} ->
Mod2 = mnesia_monitor:do_check_type(backup_module, Mod),
B#backup_args{module = Mod2};
{incremental, Name} ->
B#backup_args{prev_name = Name};
{tables, Tabs} when is_list(Tabs) ->
B#backup_args{tables = Tabs}
end.
backup_master(ClientPid, B) ->
process_flag(trap_exit, true),
try do_backup_master(B) of
Res ->
ClientPid ! {self(), ClientPid, Res}
catch _:Reason ->
ClientPid ! {self(), ClientPid, {error, {'EXIT', Reason}}}
end,
unlink(ClientPid),
exit(normal).
do_backup_master(B) ->
Name = B#backup_args.name,
B2 = safe_apply(B, open_write, [B#backup_args.opaque]),
B3 = safe_write(B2, [backup_log_header()]),
case mnesia_checkpoint:tables_and_cookie(Name) of
{ok, AllTabs, Cookie} ->
Tabs = select_tables(AllTabs, B3),
B4 = B3#backup_args{cookie = Cookie},
%% Always put schema first in backup file
B5 = backup_schema(B4, Tabs),
B6 = lists:foldl(fun backup_tab/2, B5, Tabs -- [schema]),
safe_apply(B6, commit_write, [B6#backup_args.opaque]),
ok;
{error, Reason} ->
abort_write(B3, {?MODULE, backup_master}, [B], {error, Reason})
end.
select_tables(AllTabs, B) ->
Tabs =
case B#backup_args.tables of
all -> AllTabs;
SomeTabs when is_list(SomeTabs) -> SomeTabs
end,
case B#backup_args.scope of
global ->
Tabs;
local ->
Name = B#backup_args.name,
[T || T <- Tabs, mnesia_checkpoint:most_local_node(Name, T) == {ok, node()}]
end.
safe_write(B, []) ->
B;
safe_write(B, Recs) ->
safe_apply(B, write, [B#backup_args.opaque, Recs]).
backup_schema(B, Tabs) ->
case lists:member(schema, Tabs) of
true ->
backup_tab(schema, B);
false ->
Defs = [{schema, T, mnesia_schema:get_create_list(T)} || T <- Tabs],
safe_write(B, Defs)
end.
safe_apply(B, write, [_, Items]) when Items == [] ->
B;
safe_apply(B, What, Args) ->
Abort = abort_write_fun(B, What, Args),
receive
{'EXIT', Pid, R} -> Abort({'EXIT', Pid, R})
after 0 ->
Mod = B#backup_args.module,
try apply(Mod, What, Args) of
{ok, Opaque} -> B#backup_args{opaque=Opaque};
{error, R} -> Abort(R)
catch _:R -> Abort(R)
end
end.
-spec abort_write_fun(_, _, _) -> fun((_) -> no_return()).
abort_write_fun(B, What, Args) ->
fun(R) -> abort_write(B, What, Args, R) end.
abort_write(B, What, Args, Reason) ->
Mod = B#backup_args.module,
Opaque = B#backup_args.opaque,
dbg_out("Failed to perform backup. M=~p:F=~p:A=~p -> ~p~n",
[Mod, What, Args, Reason]),
try apply(Mod, abort_write, [Opaque]) of
{ok, _Res} -> throw({error, Reason})
catch _:Other ->
error("Failed to abort backup. ~p:~p~p -> ~p~n",
[Mod, abort_write, [Opaque], Other]),
throw({error, Reason})
end.
backup_tab(Tab, B) ->
Name = B#backup_args.name,
case mnesia_checkpoint:most_local_node(Name, Tab) of
{ok, Node} when Node == node() ->
tab_copier(self(), B, Tab);
{ok, Node} ->
RemoteB = B,
Pid = spawn_link(Node, ?MODULE, tab_copier, [self(), RemoteB, Tab]),
RecName = val({Tab, record_name}),
tab_receiver(Pid, B, Tab, RecName, 0);
{error, Reason} ->
abort_write(B, {?MODULE, backup_tab}, [Tab, B], {error, Reason})
end.
tab_copier(Pid, B, Tab) when is_record(B, backup_args) ->
%% Intentional crash at exit
Name = B#backup_args.name,
PrevName = B#backup_args.prev_name,
{FirstName, FirstSource} = select_source(Tab, Name, PrevName),
?eval_debug_fun({?MODULE, tab_copier, pre}, [{name, Name}, {tab, Tab}]),
Res = handle_more(Pid, B, Tab, FirstName, FirstSource, Name),
?eval_debug_fun({?MODULE, tab_copier, post}, [{name, Name}, {tab, Tab}]),
handle_last(Pid, Res).
select_source(Tab, Name, PrevName) ->
if
Tab == schema ->
%% Always full backup of schema
{Name, table};
Name == PrevName ->
%% Full backup
{Name, table};
true ->
%% Wants incremental backup
case mnesia_checkpoint:most_local_node(PrevName, Tab) of
{ok, Node} when Node == node() ->
%% Accept incremental backup
{PrevName, retainer};
_ ->
%% Do a full backup anyway
dbg_out("Incremental backup escalated to full backup: ~p~n", [Tab]),
{Name, table}
end
end.
handle_more(Pid, B, Tab, FirstName, FirstSource, Name) ->
Acc = {0, B},
case {mnesia_checkpoint:really_retain(Name, Tab),
mnesia_checkpoint:really_retain(FirstName, Tab)} of
{true, true} ->
Acc2 = iterate(B, FirstName, Tab, Pid, FirstSource, latest, first, Acc),
iterate(B, Name, Tab, Pid, retainer, checkpoint, last, Acc2);
{false, false}->
%% Put the dumped file in the backup
%% instead of the ram table. Does
%% only apply to ram_copies.
iterate(B, Name, Tab, Pid, retainer, checkpoint, last, Acc);
Bad ->
Reason = {"Checkpoints for incremental backup must have same "
"setting of ram_overrides_dump",
Tab, Name, FirstName, Bad},
abort_write(B, {?MODULE, backup_tab}, [Tab, B], {error, Reason})
end.
handle_last(Pid, {_Count, B}) when Pid == self() ->
B;
handle_last(Pid, _Acc) ->
unlink(Pid),
Pid ! {self(), {last, {ok, dummy}}},
exit(normal).
iterate(B, Name, Tab, Pid, Source, Age, Pass, Acc) ->
Fun =
if
Pid == self() ->
RecName = val({Tab, record_name}),
fun(Recs, A) -> copy_records(RecName, Tab, Recs, A) end;
true ->
fun(Recs, A) -> send_records(Pid, Tab, Recs, Pass, A) end
end,
case mnesia_checkpoint:iterate(Name, Tab, Fun, Acc, Source, Age) of
{ok, Acc2} ->
Acc2;
{error, Reason} ->
R = {error, {"Tab copier iteration failed", Reason}},
abort_write(B, {?MODULE, iterate}, [self(), B, Tab], R)
end.
copy_records(_RecName, _Tab, [], Acc) ->
Acc;
copy_records(RecName, Tab, Recs, {Count, B}) ->
Recs2 = rec_filter(B, Tab, RecName, Recs),
B2 = safe_write(B, Recs2),
{Count + 1, B2}.
send_records(Pid, Tab, Recs, Pass, {Count, B}) ->
receive
{Pid, more, Count} ->
if
Pass == last, Recs == [] ->
{Count, B};
true ->
Next = Count + 1,
Pid ! {self(), {more, Next, Recs}},
{Next, B}
end;
Msg ->
exit({send_records_unexpected_msg, Tab, Msg})
end.
tab_receiver(Pid, B, Tab, RecName, Slot) ->
Pid ! {self(), more, Slot},
receive
{Pid, {more, Next, Recs}} ->
Recs2 = rec_filter(B, Tab, RecName, Recs),
B2 = safe_write(B, Recs2),
tab_receiver(Pid, B2, Tab, RecName, Next);
{Pid, {last, {ok,_}}} ->
B;
{'EXIT', Pid, {error, R}} ->
Reason = {error, {"Tab copier crashed", R}},
abort_write(B, {?MODULE, remote_tab_sender}, [self(), B, Tab], Reason);
{'EXIT', Pid, R} ->
Reason = {error, {"Tab copier crashed", {'EXIT', R}}},
abort_write(B, {?MODULE, remote_tab_sender}, [self(), B, Tab], Reason);
Msg ->
R = {error, {"Tab receiver got unexpected msg", Msg}},
abort_write(B, {?MODULE, remote_tab_sender}, [self(), B, Tab], R)
end.
rec_filter(B, schema, _RecName, Recs) ->
try mnesia_bup:refresh_cookie(Recs, B#backup_args.cookie)
catch throw:{error, _Reason} ->
%% No schema table cookie
Recs
end;
rec_filter(_B, Tab, Tab, Recs) ->
Recs;
rec_filter(_B, Tab, _RecName, Recs) ->
[setelement(1, Rec, Tab) || Rec <- Recs].
ets2dcd(Tab) ->
ets2dcd(Tab, dcd).
ets2dcd(Tab, Ftype) ->
Fname =
case Ftype of
dcd -> mnesia_lib:tab2dcd(Tab);
dmp -> mnesia_lib:tab2dmp(Tab)
end,
TmpF = mnesia_lib:tab2tmp(Tab),
file:delete(TmpF),
Log = open_log({Tab, ets2dcd}, dcd_log_header(), TmpF, false),
mnesia_lib:db_fixtable(ram_copies, Tab, true),
ok = ets2dcd(mnesia_lib:db_init_chunk(ram_copies, Tab, 1000), Tab, Log),
mnesia_lib:db_fixtable(ram_copies, Tab, false),
close_log(Log),
ok = file:rename(TmpF, Fname),
%% Remove old log data which is now in the new dcd.
%% No one else should be accessing this file!
file:delete(mnesia_lib:tab2dcl(Tab)),
ok.
ets2dcd('$end_of_table', _Tab, _Log) ->
ok;
ets2dcd({Recs, Cont}, Tab, Log) ->
ok = disk_log:log_terms(Log, Recs),
ets2dcd(mnesia_lib:db_chunk(ram_copies, Cont), Tab, Log).
dcd2ets(Tab) ->
dcd2ets(Tab, mnesia_monitor:get_env(auto_repair)).
dcd2ets(Tab, Rep) ->
Dcd = mnesia_lib:tab2dcd(Tab),
case mnesia_lib:exists(Dcd) of
true ->
Log = open_log({Tab, dcd2ets}, dcd_log_header(), Dcd,
true, Rep, read_only),
Data = chunk_log(Log, start),
ok = insert_dcdchunk(Data, Log, Tab),
close_log(Log),
load_dcl(Tab, Rep);
false -> %% Handle old dets files, and conversion from disc_only to disc.
Fname = mnesia_lib:tab2dat(Tab),
Type = val({Tab, setorbag}),
case mnesia_lib:dets_to_ets(Tab, Tab, Fname, Type, Rep, yes) of
loaded ->
ets2dcd(Tab),
file:delete(Fname),
0;
{error, Error} ->
erlang:error({"Failed to load table from disc", [Tab, Error]})
end
end.
insert_dcdchunk({Cont, [LogH | Rest]}, Log, Tab)
when is_record(LogH, log_header),
LogH#log_header.log_kind == dcd_log,
LogH#log_header.log_version >= "1.0" ->
insert_dcdchunk({Cont, Rest}, Log, Tab);
insert_dcdchunk({Cont, Recs}, Log, Tab) ->
true = ets:insert(Tab, Recs),
insert_dcdchunk(chunk_log(Log, Cont), Log, Tab);
insert_dcdchunk(eof, _Log, _Tab) ->
ok.
load_dcl(Tab, Rep) ->
FName = mnesia_lib:tab2dcl(Tab),
case mnesia_lib:exists(FName) of
true ->
Name = {load_dcl,Tab},
open_log(Name,
dcl_log_header(),
FName,
true,
Rep,
read_only),
FirstChunk = chunk_log(Name, start),
N = insert_logchunk(FirstChunk, Name, 0),
close_log(Name),
N;
false ->
0
end.
insert_logchunk({C2, Recs}, Tab, C) ->
N = add_recs(Recs, C),
insert_logchunk(chunk_log(Tab, C2), Tab, C+N);
insert_logchunk(eof, _Tab, C) ->
C.
add_recs([{{Tab, _Key}, Val, write} | Rest], N) ->
true = ets:insert(Tab, Val),
add_recs(Rest, N+1);
add_recs([{{Tab, Key}, _Val, delete} | Rest], N) ->
true = ets:delete(Tab, Key),
add_recs(Rest, N+1);
add_recs([{{Tab, _Key}, Val, delete_object} | Rest], N) ->
true = ets:match_delete(Tab, Val),
add_recs(Rest, N+1);
add_recs([{{Tab, Key}, Val, update_counter} | Rest], N) ->
{RecName, Incr} = Val,
try
CounterVal = ets:update_counter(Tab, Key, Incr),
true = (CounterVal >= 0)
catch
error:_ when Incr < 0 ->
Zero = {RecName, Key, 0},
true = ets:insert(Tab, Zero);
error:_ ->
Zero = {RecName, Key, Incr},
true = ets:insert(Tab, Zero)
end,
add_recs(Rest, N+1);
add_recs([LogH|Rest], N)
when is_record(LogH, log_header),
LogH#log_header.log_kind == dcl_log,
LogH#log_header.log_version >= "1.0" ->
add_recs(Rest, N);
add_recs([{{Tab, _Key}, _Val, clear_table} | Rest], N) ->
Size = ets:info(Tab, size),
true = ets:delete_all_objects(Tab),
add_recs(Rest, N+Size);
add_recs([], N) ->
N.
