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Diffstat (limited to 'lib/mnesia/src/mnesia_frag.erl')
| -rw-r--r-- | lib/mnesia/src/mnesia_frag.erl | 1361 |
1 files changed, 1361 insertions, 0 deletions
diff --git a/lib/mnesia/src/mnesia_frag.erl b/lib/mnesia/src/mnesia_frag.erl new file mode 100644 index 0000000000..a2958ab461 --- /dev/null +++ b/lib/mnesia/src/mnesia_frag.erl @@ -0,0 +1,1361 @@ +%%% +%% %CopyrightBegin% +%% +%% Copyright Ericsson AB 1998-2009. 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% +%% + +%%% +%%%---------------------------------------------------------------------- +%%% Purpose : Support tables so large that they need +%%% to be divided into several fragments. +%%%---------------------------------------------------------------------- + +%header_doc_include + +-module(mnesia_frag). + +%% Callback functions when accessed within an activity +-export([ + lock/4, + write/5, delete/5, delete_object/5, + read/5, match_object/5, all_keys/4, + select/5,select/6,select_cont/3, + index_match_object/6, index_read/6, + foldl/6, foldr/6, table_info/4, + first/3, next/4, prev/4, last/3, + clear_table/4 + ]). + +%header_doc_include + +%% -behaviour(mnesia_access). + +-export([ + change_table_frag/2, + remove_node/2, + expand_cstruct/1, + lookup_frag_hash/1, + lookup_foreigners/1, + frag_names/1, + set_frag_hash/2, + local_select/4, + remote_select/4 + ]). + +-include("mnesia.hrl"). + +-define(OLD_HASH_MOD, mnesia_frag_old_hash). +-define(DEFAULT_HASH_MOD, mnesia_frag_hash). +%%-define(DEFAULT_HASH_MOD, ?OLD_HASH_MOD). %% BUGBUG: New should be default + +-record(frag_state, + {foreign_key, + n_fragments, + hash_module, + hash_state}). + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +%% Access functions + +%impl_doc_include + +%% Callback functions which provides transparent +%% access of fragmented tables from any activity +%% access context. + +lock(ActivityId, Opaque, {table , Tab}, LockKind) -> + case frag_names(Tab) of + [Tab] -> + mnesia:lock(ActivityId, Opaque, {table, Tab}, LockKind); + Frags -> + DeepNs = [mnesia:lock(ActivityId, Opaque, {table, F}, LockKind) || + F <- Frags], + mnesia_lib:uniq(lists:append(DeepNs)) + end; + +lock(ActivityId, Opaque, LockItem, LockKind) -> + mnesia:lock(ActivityId, Opaque, LockItem, LockKind). + +write(ActivityId, Opaque, Tab, Rec, LockKind) -> + Frag = record_to_frag_name(Tab, Rec), + mnesia:write(ActivityId, Opaque, Frag, Rec, LockKind). + +delete(ActivityId, Opaque, Tab, Key, LockKind) -> + Frag = key_to_frag_name(Tab, Key), + mnesia:delete(ActivityId, Opaque, Frag, Key, LockKind). + +delete_object(ActivityId, Opaque, Tab, Rec, LockKind) -> + Frag = record_to_frag_name(Tab, Rec), + mnesia:delete_object(ActivityId, Opaque, Frag, Rec, LockKind). + +read(ActivityId, Opaque, Tab, Key, LockKind) -> + Frag = key_to_frag_name(Tab, Key), + mnesia:read(ActivityId, Opaque, Frag, Key, LockKind). + +match_object(ActivityId, Opaque, Tab, HeadPat, LockKind) -> + MatchSpec = [{HeadPat, [], ['$_']}], + select(ActivityId, Opaque, Tab, MatchSpec, LockKind). + +select(ActivityId, Opaque, Tab, MatchSpec, LockKind) -> + do_select(ActivityId, Opaque, Tab, MatchSpec, LockKind). + + +select(ActivityId, Opaque, Tab, MatchSpec, Limit, LockKind) -> + init_select(ActivityId, Opaque, Tab, MatchSpec, Limit, LockKind). + + +all_keys(ActivityId, Opaque, Tab, LockKind) -> + Match = [mnesia:all_keys(ActivityId, Opaque, Frag, LockKind) + || Frag <- frag_names(Tab)], + lists:append(Match). + +clear_table(ActivityId, Opaque, Tab, Obj) -> + [mnesia:clear_table(ActivityId, Opaque, Frag, Obj) || Frag <- frag_names(Tab)], + ok. + +index_match_object(ActivityId, Opaque, Tab, Pat, Attr, LockKind) -> + Match = + [mnesia:index_match_object(ActivityId, Opaque, Frag, Pat, Attr, LockKind) + || Frag <- frag_names(Tab)], + lists:append(Match). + +index_read(ActivityId, Opaque, Tab, Key, Attr, LockKind) -> + Match = + [mnesia:index_read(ActivityId, Opaque, Frag, Key, Attr, LockKind) + || Frag <- frag_names(Tab)], + lists:append(Match). + +foldl(ActivityId, Opaque, Fun, Acc, Tab, LockKind) -> + Fun2 = fun(Frag, A) -> + mnesia:foldl(ActivityId, Opaque, Fun, A, Frag, LockKind) + end, + lists:foldl(Fun2, Acc, frag_names(Tab)). + +foldr(ActivityId, Opaque, Fun, Acc, Tab, LockKind) -> + Fun2 = fun(Frag, A) -> + mnesia:foldr(ActivityId, Opaque, Fun, A, Frag, LockKind) + end, + lists:foldr(Fun2, Acc, frag_names(Tab)). + +table_info(ActivityId, Opaque, {Tab, Key}, Item) -> + Frag = key_to_frag_name(Tab, Key), + table_info2(ActivityId, Opaque, Tab, Frag, Item); +table_info(ActivityId, Opaque, Tab, Item) -> + table_info2(ActivityId, Opaque, Tab, Tab, Item). + +table_info2(ActivityId, Opaque, Tab, Frag, Item) -> + case Item of + size -> + SumFun = fun({_, Size}, Acc) -> Acc + Size end, + lists:foldl(SumFun, 0, frag_size(ActivityId, Opaque, Tab)); + memory -> + SumFun = fun({_, Size}, Acc) -> Acc + Size end, + lists:foldl(SumFun, 0, frag_memory(ActivityId, Opaque, Tab)); + base_table -> + lookup_prop(Tab, base_table); + node_pool -> + lookup_prop(Tab, node_pool); + n_fragments -> + FH = lookup_frag_hash(Tab), + FH#frag_state.n_fragments; + foreign_key -> + FH = lookup_frag_hash(Tab), + FH#frag_state.foreign_key; + foreigners -> + lookup_foreigners(Tab); + n_ram_copies -> + length(val({Tab, ram_copies})); + n_disc_copies -> + length(val({Tab, disc_copies})); + n_disc_only_copies -> + length(val({Tab, disc_only_copies})); + + frag_names -> + frag_names(Tab); + frag_dist -> + frag_dist(Tab); + frag_size -> + frag_size(ActivityId, Opaque, Tab); + frag_memory -> + frag_memory(ActivityId, Opaque, Tab); + _ -> + mnesia:table_info(ActivityId, Opaque, Frag, Item) + end. + +first(ActivityId, Opaque, Tab) -> + case ?catch_val({Tab, frag_hash}) of + {'EXIT', _} -> + mnesia:first(ActivityId, Opaque, Tab); + FH -> + FirstFrag = Tab, + case mnesia:first(ActivityId, Opaque, FirstFrag) of + '$end_of_table' -> + search_first(ActivityId, Opaque, Tab, 1, FH); + Next -> + Next + end + end. + +search_first(ActivityId, Opaque, Tab, N, FH) when N =< FH#frag_state.n_fragments -> + NextN = N + 1, + NextFrag = n_to_frag_name(Tab, NextN), + case mnesia:first(ActivityId, Opaque, NextFrag) of + '$end_of_table' -> + search_first(ActivityId, Opaque, Tab, NextN, FH); + Next -> + Next + end; +search_first(_ActivityId, _Opaque, _Tab, _N, _FH) -> + '$end_of_table'. + +last(ActivityId, Opaque, Tab) -> + case ?catch_val({Tab, frag_hash}) of + {'EXIT', _} -> + mnesia:last(ActivityId, Opaque, Tab); + FH -> + LastN = FH#frag_state.n_fragments, + search_last(ActivityId, Opaque, Tab, LastN, FH) + end. + +search_last(ActivityId, Opaque, Tab, N, FH) when N >= 1 -> + Frag = n_to_frag_name(Tab, N), + case mnesia:last(ActivityId, Opaque, Frag) of + '$end_of_table' -> + PrevN = N - 1, + search_last(ActivityId, Opaque, Tab, PrevN, FH); + Prev -> + Prev + end; +search_last(_ActivityId, _Opaque, _Tab, _N, _FH) -> + '$end_of_table'. + +prev(ActivityId, Opaque, Tab, Key) -> + case ?catch_val({Tab, frag_hash}) of + {'EXIT', _} -> + mnesia:prev(ActivityId, Opaque, Tab, Key); + FH -> + N = key_to_n(FH, Key), + Frag = n_to_frag_name(Tab, N), + case mnesia:prev(ActivityId, Opaque, Frag, Key) of + '$end_of_table' -> + search_prev(ActivityId, Opaque, Tab, N); + Prev -> + Prev + end + end. + +search_prev(ActivityId, Opaque, Tab, N) when N > 1 -> + PrevN = N - 1, + PrevFrag = n_to_frag_name(Tab, PrevN), + case mnesia:last(ActivityId, Opaque, PrevFrag) of + '$end_of_table' -> + search_prev(ActivityId, Opaque, Tab, PrevN); + Prev -> + Prev + end; +search_prev(_ActivityId, _Opaque, _Tab, _N) -> + '$end_of_table'. + +next(ActivityId, Opaque, Tab, Key) -> + case ?catch_val({Tab, frag_hash}) of + {'EXIT', _} -> + mnesia:next(ActivityId, Opaque, Tab, Key); + FH -> + N = key_to_n(FH, Key), + Frag = n_to_frag_name(Tab, N), + case mnesia:next(ActivityId, Opaque, Frag, Key) of + '$end_of_table' -> + search_next(ActivityId, Opaque, Tab, N, FH); + Prev -> + Prev + end + end. + +search_next(ActivityId, Opaque, Tab, N, FH) when N < FH#frag_state.n_fragments -> + NextN = N + 1, + NextFrag = n_to_frag_name(Tab, NextN), + case mnesia:first(ActivityId, Opaque, NextFrag) of + '$end_of_table' -> + search_next(ActivityId, Opaque, Tab, NextN, FH); + Next -> + Next + end; +search_next(_ActivityId, _Opaque, _Tab, _N, _FH) -> + '$end_of_table'. + +%impl_doc_include + +frag_size(ActivityId, Opaque, Tab) -> + [{F, remote_table_info(ActivityId, Opaque, F, size)} || F <- frag_names(Tab)]. + +frag_memory(ActivityId, Opaque, Tab) -> + [{F, remote_table_info(ActivityId, Opaque, F, memory)} || F <- frag_names(Tab)]. + +remote_table_info(ActivityId, Opaque, Tab, Item) -> + N = val({Tab, where_to_read}), + case rpc:call(N, mnesia, table_info, [ActivityId, Opaque, Tab, Item]) of + {badrpc, _} -> + mnesia:abort({no_exists, Tab, Item}); + Info -> + Info + end. + +init_select(Tid,Opaque,Tab,Pat,Limit,LockKind) -> + case ?catch_val({Tab, frag_hash}) of + {'EXIT', _} -> + mnesia:select(Tid, Opaque, Tab, Pat, Limit,LockKind); + FH -> + FragNumbers = verify_numbers(FH,Pat), + Fun = fun(Num) -> + Name = n_to_frag_name(Tab, Num), + Node = val({Name, where_to_read}), + Storage = mnesia_lib:storage_type_at_node(Node, Name), + mnesia:lock(Tid, Opaque, {table, Name}, LockKind), + {Name, Node, Storage} + end, + [{FTab,Node,Type}|NameNodes] = lists:map(Fun, FragNumbers), + InitFun = fun(FixedSpec) -> mnesia:dirty_sel_init(Node,FTab,FixedSpec,Limit,Type) end, + Res = mnesia:fun_select(Tid,Opaque,FTab,Pat,LockKind,FTab,InitFun,Limit,Node,Type), + frag_sel_cont(Res, NameNodes, {Pat,LockKind,Limit}) + end. + +select_cont(_Tid,_,{frag_cont, '$end_of_table', [],_}) -> '$end_of_table'; +select_cont(Tid,Ts,{frag_cont, '$end_of_table', [{Tab,Node,Type}|Rest],Args}) -> + {Spec,LockKind,Limit} = Args, + InitFun = fun(FixedSpec) -> mnesia:dirty_sel_init(Node,Tab,FixedSpec,Limit,Type) end, + Res = mnesia:fun_select(Tid,Ts,Tab,Spec,LockKind,Tab,InitFun,Limit,Node,Type), + frag_sel_cont(Res, Rest, Args); +select_cont(Tid,Ts,{frag_cont, Cont, TabL, Args}) -> + frag_sel_cont(mnesia:select_cont(Tid,Ts,Cont),TabL,Args); +select_cont(Tid,Ts,Else) -> %% Not a fragmented table + mnesia:select_cont(Tid,Ts,Else). + +frag_sel_cont('$end_of_table', [],_) -> + '$end_of_table'; +frag_sel_cont('$end_of_table', TabL,Args) -> + {[], {frag_cont, '$end_of_table', TabL,Args}}; +frag_sel_cont({Recs,Cont}, TabL,Args) -> + {Recs, {frag_cont, Cont, TabL,Args}}. + +do_select(ActivityId, Opaque, Tab, MatchSpec, LockKind) -> + case ?catch_val({Tab, frag_hash}) of + {'EXIT', _} -> + mnesia:select(ActivityId, Opaque, Tab, MatchSpec, LockKind); + FH -> + FragNumbers = verify_numbers(FH,MatchSpec), + Fun = fun(Num) -> + Name = n_to_frag_name(Tab, Num), + Node = val({Name, where_to_read}), + mnesia:lock(ActivityId, Opaque, {table, Name}, LockKind), + {Name, Node} + end, + NameNodes = lists:map(Fun, FragNumbers), + SelectAllFun = + fun(PatchedMatchSpec) -> + Match = [mnesia:dirty_select(Name, PatchedMatchSpec) + || {Name, _Node} <- NameNodes], + lists:append(Match) + end, + case [{Name, Node} || {Name, Node} <- NameNodes, Node /= node()] of + [] -> + %% All fragments are local + mnesia:fun_select(ActivityId, Opaque, Tab, MatchSpec, none, '_', SelectAllFun); + RemoteNameNodes -> + Type = val({Tab,setorbag}), + SelectFun = + fun(PatchedMatchSpec) -> + Ref = make_ref(), + Args = [self(), Ref, RemoteNameNodes, PatchedMatchSpec], + Pid = spawn_link(?MODULE, local_select, Args), + LocalMatch0 = [mnesia:dirty_select(Name, PatchedMatchSpec) + || {Name, Node} <- NameNodes, Node == node()], + LocalMatch = case Type of + ordered_set -> lists:merge(LocalMatch0); + _ -> lists:append(LocalMatch0) + end, + OldSelectFun = fun() -> SelectAllFun(PatchedMatchSpec) end, + local_collect(Ref, Pid, Type, LocalMatch, OldSelectFun) + end, + mnesia:fun_select(ActivityId, Opaque, Tab, MatchSpec, none, '_', SelectFun) + end + end. + +verify_numbers(FH,MatchSpec) -> + HashState = FH#frag_state.hash_state, + FragNumbers = + case FH#frag_state.hash_module of + HashMod when HashMod == ?DEFAULT_HASH_MOD -> + ?DEFAULT_HASH_MOD:match_spec_to_frag_numbers(HashState, MatchSpec); + HashMod -> + HashMod:match_spec_to_frag_numbers(HashState, MatchSpec) + end, + N = FH#frag_state.n_fragments, + VerifyFun = fun(F) when is_integer(F), F >= 1, F =< N -> false; + (_F) -> true + end, + case catch lists:filter(VerifyFun, FragNumbers) of + [] -> + FragNumbers; + BadFrags -> + mnesia:abort({"match_spec_to_frag_numbers: Fragment numbers out of range", + BadFrags, {range, 1, N}}) + end. + +local_select(ReplyTo, Ref, RemoteNameNodes, MatchSpec) -> + RemoteNodes = mnesia_lib:uniq([Node || {_Name, Node} <- RemoteNameNodes]), + Args = [ReplyTo, Ref, RemoteNameNodes, MatchSpec], + {Replies, BadNodes} = rpc:multicall(RemoteNodes, ?MODULE, remote_select, Args), + case mnesia_lib:uniq(Replies) -- [ok] of + [] when BadNodes == [] -> + ReplyTo ! {local_select, Ref, ok}; + _ when BadNodes /= [] -> + ReplyTo ! {local_select, Ref, {error, {node_not_running, hd(BadNodes)}}}; + [{badrpc, {'EXIT', Reason}} | _] -> + ReplyTo ! {local_select, Ref, {error, Reason}}; + [Reason | _] -> + ReplyTo ! {local_select, Ref, {error, Reason}} + end, + unlink(ReplyTo), + exit(normal). + +remote_select(ReplyTo, Ref, NameNodes, MatchSpec) -> + do_remote_select(ReplyTo, Ref, NameNodes, MatchSpec). + +do_remote_select(ReplyTo, Ref, [{Name, Node} | NameNodes], MatchSpec) -> + if + Node == node() -> + Res = (catch {ok, mnesia:dirty_select(Name, MatchSpec)}), + ReplyTo ! {remote_select, Ref, Node, Res}, + do_remote_select(ReplyTo, Ref, NameNodes, MatchSpec); + true -> + do_remote_select(ReplyTo, Ref, NameNodes, MatchSpec) + end; +do_remote_select(_ReplyTo, _Ref, [], _MatchSpec) -> + ok. + +local_collect(Ref, Pid, Type, LocalMatch, OldSelectFun) -> + receive + {local_select, Ref, LocalRes} -> + remote_collect(Ref, Type, LocalRes, LocalMatch, OldSelectFun); + {'EXIT', Pid, Reason} -> + remote_collect(Ref, Type, {error, Reason}, [], OldSelectFun) + end. + +remote_collect(Ref, Type, LocalRes = ok, Acc, OldSelectFun) -> + receive + {remote_select, Ref, Node, RemoteRes} -> + case RemoteRes of + {ok, RemoteMatch} -> + Matches = case Type of + ordered_set -> lists:merge(RemoteMatch, Acc); + _ -> RemoteMatch ++ Acc + end, + remote_collect(Ref, Type, LocalRes, Matches, OldSelectFun); + _ -> + remote_collect(Ref, Type, {error, {node_not_running, Node}}, [], OldSelectFun) + end + after 0 -> + Acc + end; +remote_collect(Ref, Type, LocalRes = {error, Reason}, _Acc, OldSelectFun) -> + receive + {remote_select, Ref, _Node, _RemoteRes} -> + remote_collect(Ref, Type, LocalRes, [], OldSelectFun) + after 0 -> + mnesia:abort(Reason) + end. + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +%% Returns a list of cstructs + +expand_cstruct(Cs) -> + expand_cstruct(Cs, create). + +expand_cstruct(Cs, Mode) -> + Tab = Cs#cstruct.name, + Props = Cs#cstruct.frag_properties, + mnesia_schema:verify({alt, [nil, list]}, mnesia_lib:etype(Props), + {badarg, Tab, Props}), + %% Verify keys + ValidKeys = [foreign_key, n_fragments, node_pool, + n_ram_copies, n_disc_copies, n_disc_only_copies, + hash_module, hash_state], + Keys = mnesia_schema:check_keys(Tab, Props, ValidKeys), + mnesia_schema:check_duplicates(Tab, Keys), + + %% Pick fragmentation props + ForeignKey = mnesia_schema:pick(Tab, foreign_key, Props, undefined), + {ForeignKey2, N, Pool, DefaultNR, DefaultND, DefaultNDO} = + pick_props(Tab, Cs, ForeignKey), + + %% Verify node_pool + BadPool = {bad_type, Tab, {node_pool, Pool}}, + mnesia_schema:verify(list, mnesia_lib:etype(Pool), BadPool), + NotAtom = fun(A) when is_atom(A) -> false; + (_A) -> true + end, + mnesia_schema:verify([], [P || P <- Pool, NotAtom(P)], BadPool), + + NR = mnesia_schema:pick(Tab, n_ram_copies, Props, 0), + ND = mnesia_schema:pick(Tab, n_disc_copies, Props, 0), + NDO = mnesia_schema:pick(Tab, n_disc_only_copies, Props, 0), + + PosInt = fun(I) when is_integer(I), I >= 0 -> true; + (_I) -> false + end, + mnesia_schema:verify(true, PosInt(NR), + {bad_type, Tab, {n_ram_copies, NR}}), + mnesia_schema:verify(true, PosInt(ND), + {bad_type, Tab, {n_disc_copies, ND}}), + mnesia_schema:verify(true, PosInt(NDO), + {bad_type, Tab, {n_disc_only_copies, NDO}}), + + %% Verify n_fragments + Cs2 = verify_n_fragments(N, Cs, Mode), + + %% Verify hash callback + HashMod = mnesia_schema:pick(Tab, hash_module, Props, ?DEFAULT_HASH_MOD), + HashState = mnesia_schema:pick(Tab, hash_state, Props, undefined), + HashState2 = HashMod:init_state(Tab, HashState), %% BUGBUG: Catch? + + FH = #frag_state{foreign_key = ForeignKey2, + n_fragments = 1, + hash_module = HashMod, + hash_state = HashState2}, + if + NR == 0, ND == 0, NDO == 0 -> + do_expand_cstruct(Cs2, FH, N, Pool, DefaultNR, DefaultND, DefaultNDO, Mode); + true -> + do_expand_cstruct(Cs2, FH, N, Pool, NR, ND, NDO, Mode) + end. + +do_expand_cstruct(Cs, FH, N, Pool, NR, ND, NDO, Mode) -> + Tab = Cs#cstruct.name, + + LC = Cs#cstruct.local_content, + mnesia_schema:verify(false, LC, + {combine_error, Tab, {local_content, LC}}), + + Snmp = Cs#cstruct.snmp, + mnesia_schema:verify([], Snmp, + {combine_error, Tab, {snmp, Snmp}}), + + %% Add empty fragments + CommonProps = [{base_table, Tab}], + Cs2 = Cs#cstruct{frag_properties = lists:sort(CommonProps)}, + expand_frag_cstructs(N, NR, ND, NDO, Cs2, Pool, Pool, FH, Mode). + +verify_n_fragments(N, Cs, Mode) when is_integer(N), N >= 1 -> + case Mode of + create -> + Cs#cstruct{ram_copies = [], + disc_copies = [], + disc_only_copies = []}; + activate -> + Reason = {combine_error, Cs#cstruct.name, {n_fragments, N}}, + mnesia_schema:verify(1, N, Reason), + Cs + end; +verify_n_fragments(N, Cs, _Mode) -> + mnesia:abort({bad_type, Cs#cstruct.name, {n_fragments, N}}). + +pick_props(Tab, Cs, {ForeignTab, Attr}) -> + mnesia_schema:verify(true, ForeignTab /= Tab, + {combine_error, Tab, {ForeignTab, Attr}}), + Props = Cs#cstruct.frag_properties, + Attrs = Cs#cstruct.attributes, + + ForeignKey = lookup_prop(ForeignTab, foreign_key), + ForeignN = lookup_prop(ForeignTab, n_fragments), + ForeignPool = lookup_prop(ForeignTab, node_pool), + N = mnesia_schema:pick(Tab, n_fragments, Props, ForeignN), + Pool = mnesia_schema:pick(Tab, node_pool, Props, ForeignPool), + + mnesia_schema:verify(ForeignN, N, + {combine_error, Tab, {n_fragments, N}, + ForeignTab, {n_fragments, ForeignN}}), + + mnesia_schema:verify(ForeignPool, Pool, + {combine_error, Tab, {node_pool, Pool}, + ForeignTab, {node_pool, ForeignPool}}), + + mnesia_schema:verify(undefined, ForeignKey, + {combine_error, Tab, + "Multiple levels of foreign_key dependencies", + {ForeignTab, Attr}, ForeignKey}), + + Key = {ForeignTab, mnesia_schema:attr_to_pos(Attr, Attrs)}, + DefaultNR = length(val({ForeignTab, ram_copies})), + DefaultND = length(val({ForeignTab, disc_copies})), + DefaultNDO = length(val({ForeignTab, disc_only_copies})), + {Key, N, Pool, DefaultNR, DefaultND, DefaultNDO}; +pick_props(Tab, Cs, undefined) -> + Props = Cs#cstruct.frag_properties, + DefaultN = 1, + DefaultPool = mnesia:system_info(db_nodes), + N = mnesia_schema:pick(Tab, n_fragments, Props, DefaultN), + Pool = mnesia_schema:pick(Tab, node_pool, Props, DefaultPool), + DefaultNR = 1, + DefaultND = 0, + DefaultNDO = 0, + {undefined, N, Pool, DefaultNR, DefaultND, DefaultNDO}; +pick_props(Tab, _Cs, BadKey) -> + mnesia:abort({bad_type, Tab, {foreign_key, BadKey}}). + +expand_frag_cstructs(N, NR, ND, NDO, CommonCs, Dist, Pool, FH, Mode) + when N > 1, Mode == create -> + Frag = n_to_frag_name(CommonCs#cstruct.name, N), + Cs = CommonCs#cstruct{name = Frag}, + {Cs2, RevModDist, RestDist} = set_frag_nodes(NR, ND, NDO, Cs, Dist, []), + ModDist = lists:reverse(RevModDist), + Dist2 = rearrange_dist(Cs, ModDist, RestDist, Pool), + %% Adjusts backwards, but it doesn't matter. + {FH2, _FromFrags, _AdditionalWriteFrags} = adjust_before_split(FH), + CsList = expand_frag_cstructs(N - 1, NR, ND, NDO, CommonCs, Dist2, Pool, FH2, Mode), + [Cs2 | CsList]; +expand_frag_cstructs(1, NR, ND, NDO, CommonCs, Dist, Pool, FH, Mode) -> + BaseProps = CommonCs#cstruct.frag_properties ++ + [{foreign_key, FH#frag_state.foreign_key}, + {hash_module, FH#frag_state.hash_module}, + {hash_state, FH#frag_state.hash_state}, + {n_fragments, FH#frag_state.n_fragments}, + {node_pool, Pool} + ], + BaseCs = CommonCs#cstruct{frag_properties = lists:sort(BaseProps)}, + case Mode of + activate -> + [BaseCs]; + create -> + {BaseCs2, _, _} = set_frag_nodes(NR, ND, NDO, BaseCs, Dist, []), + [BaseCs2] + end. + +set_frag_nodes(NR, ND, NDO, Cs, [Head | Tail], Acc) when NR > 0 -> + Pos = #cstruct.ram_copies, + {Cs2, Head2} = set_frag_node(Cs, Pos, Head), + set_frag_nodes(NR - 1, ND, NDO, Cs2, Tail, [Head2 | Acc]); +set_frag_nodes(NR, ND, NDO, Cs, [Head | Tail], Acc) when ND > 0 -> + Pos = #cstruct.disc_copies, + {Cs2, Head2} = set_frag_node(Cs, Pos, Head), + set_frag_nodes(NR, ND - 1, NDO, Cs2, Tail, [Head2 | Acc]); +set_frag_nodes(NR, ND, NDO, Cs, [Head | Tail], Acc) when NDO > 0 -> + Pos = #cstruct.disc_only_copies, + {Cs2, Head2} = set_frag_node(Cs, Pos, Head), + set_frag_nodes(NR, ND, NDO - 1, Cs2, Tail, [Head2 | Acc]); +set_frag_nodes(0, 0, 0, Cs, RestDist, ModDist) -> + {Cs, ModDist, RestDist}; +set_frag_nodes(_, _, _, Cs, [], _) -> + mnesia:abort({combine_error, Cs#cstruct.name, "Too few nodes in node_pool"}). + +set_frag_node(Cs, Pos, Head) -> + Ns = element(Pos, Cs), + {Node, Count2} = + case Head of + {N, Count} when is_atom(N), is_integer(Count), Count >= 0 -> + {N, Count + 1}; + N when is_atom(N) -> + {N, 1}; + BadNode -> + mnesia:abort({bad_type, Cs#cstruct.name, BadNode}) + end, + mnesia_schema:verify(true, + lists:member(Node, val({current,db_nodes})), + {not_active, Cs#cstruct.name, Node}), + Cs2 = setelement(Pos, Cs, [Node | Ns]), + {Cs2, {Node, Count2}}. + +rearrange_dist(Cs, [{Node, Count} | ModDist], Dist, Pool) -> + Dist2 = insert_dist(Cs, Node, Count, Dist, Pool), + rearrange_dist(Cs, ModDist, Dist2, Pool); +rearrange_dist(_Cs, [], Dist, _) -> + Dist. + +insert_dist(Cs, Node, Count, [Head | Tail], Pool) -> + case Head of + {Node2, Count2} when is_atom(Node2), is_integer(Count2), Count2 >= 0 -> + case node_diff(Node, Count, Node2, Count2, Pool) of + less -> + [{Node, Count}, Head | Tail]; + greater -> + [Head | insert_dist(Cs, Node, Count, Tail, Pool)] + end; + Node2 when is_atom(Node2) -> + insert_dist(Cs, Node, Count, [{Node2, 0} | Tail], Pool); + BadNode -> + mnesia:abort({bad_type, Cs#cstruct.name, BadNode}) + end; +insert_dist(_Cs, Node, Count, [], _Pool) -> + [{Node, Count}]; +insert_dist(_Cs, _Node, _Count, Dist, _Pool) -> + mnesia:abort({bad_type, Dist}). + +node_diff(_Node, Count, _Node2, Count2, _Pool) when Count < Count2 -> + less; +node_diff(Node, Count, Node2, Count2, Pool) when Count == Count2 -> + Pos = list_pos(Node, Pool, 1), + Pos2 = list_pos(Node2, Pool, 1), + if + Pos < Pos2 -> + less; + Pos > Pos2 -> + greater + end; +node_diff(_Node, Count, _Node2, Count2, _Pool) when Count > Count2 -> + greater. + +%% Returns position of element in list +list_pos(H, [H | _T], Pos) -> + Pos; +list_pos(E, [_H | T], Pos) -> + list_pos(E, T, Pos + 1). + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +%% Switch function for changing of table fragmentation +%% +%% Returns a list of lists of schema ops + +change_table_frag(Tab, {activate, FragProps}) -> + make_activate(Tab, FragProps); +change_table_frag(Tab, deactivate) -> + make_deactivate(Tab); +change_table_frag(Tab, {add_frag, SortedNodes}) -> + make_multi_add_frag(Tab, SortedNodes); +change_table_frag(Tab, del_frag) -> + make_multi_del_frag(Tab); +change_table_frag(Tab, {add_node, Node}) -> + make_multi_add_node(Tab, Node); +change_table_frag(Tab, {del_node, Node}) -> + make_multi_del_node(Tab, Node); +change_table_frag(Tab, Change) -> + mnesia:abort({bad_type, Tab, Change}). + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +%% Turn a normal table into a fragmented table +%% +%% The storage type must be the same on all nodes + +make_activate(Tab, Props) -> + Cs = mnesia_schema:incr_version(val({Tab, cstruct})), + mnesia_schema:ensure_active(Cs), + case Cs#cstruct.frag_properties of + [] -> + Cs2 = Cs#cstruct{frag_properties = Props}, + [Cs3] = expand_cstruct(Cs2, activate), + TabDef = mnesia_schema:cs2list(Cs3), + Op = {op, change_table_frag, activate, TabDef}, + [[Op]]; + BadProps -> + mnesia:abort({already_exists, Tab, {frag_properties, BadProps}}) + end. + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +%% Turn a table into a normal defragmented table + +make_deactivate(Tab) -> + Cs = mnesia_schema:incr_version(val({Tab, cstruct})), + mnesia_schema:ensure_active(Cs), + Foreigners = lookup_foreigners(Tab), + BaseTab = lookup_prop(Tab, base_table), + FH = lookup_frag_hash(Tab), + if + BaseTab /= Tab -> + mnesia:abort({combine_error, Tab, "Not a base table"}); + Foreigners /= [] -> + mnesia:abort({combine_error, Tab, "Too many foreigners", Foreigners}); + FH#frag_state.n_fragments > 1 -> + mnesia:abort({combine_error, Tab, "Too many fragments"}); + true -> + Cs2 = Cs#cstruct{frag_properties = []}, + TabDef = mnesia_schema:cs2list(Cs2), + Op = {op, change_table_frag, deactivate, TabDef}, + [[Op]] + end. + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +%% Add a fragment to a fragmented table and fill it with half of +%% the records from one of the old fragments + +make_multi_add_frag(Tab, SortedNs) when is_list(SortedNs) -> + verify_multi(Tab), + Ops = make_add_frag(Tab, SortedNs), + + %% Propagate to foreigners + MoreOps = [make_add_frag(T, SortedNs) || T <- lookup_foreigners(Tab)], + [Ops | MoreOps]; +make_multi_add_frag(Tab, SortedNs) -> + mnesia:abort({bad_type, Tab, SortedNs}). + +verify_multi(Tab) -> + FH = lookup_frag_hash(Tab), + ForeignKey = FH#frag_state.foreign_key, + mnesia_schema:verify(undefined, ForeignKey, + {combine_error, Tab, + "Op only allowed via foreign table", + {foreign_key, ForeignKey}}). + +make_frag_names_and_acquire_locks(Tab, N, FragIndecies, DoNotLockN) -> + mnesia_schema:get_tid_ts_and_lock(Tab, write), + Fun = fun(Index, FN) -> + if + DoNotLockN == true, Index == N -> + Name = n_to_frag_name(Tab, Index), + setelement(Index, FN, Name); + true -> + Name = n_to_frag_name(Tab, Index), + mnesia_schema:get_tid_ts_and_lock(Name, write), + setelement(Index , FN, Name) + end + end, + FragNames = erlang:make_tuple(N, undefined), + lists:foldl(Fun, FragNames, FragIndecies). + +make_add_frag(Tab, SortedNs) -> + Cs = mnesia_schema:incr_version(val({Tab, cstruct})), + mnesia_schema:ensure_active(Cs), + FH = lookup_frag_hash(Tab), + {FH2, FromIndecies, WriteIndecies} = adjust_before_split(FH), + N = FH2#frag_state.n_fragments, + FragNames = make_frag_names_and_acquire_locks(Tab, N, WriteIndecies, true), + NewFrag = element(N, FragNames), + + NR = length(Cs#cstruct.ram_copies), + ND = length(Cs#cstruct.disc_copies), + NDO = length(Cs#cstruct.disc_only_copies), + NewCs = Cs#cstruct{name = NewFrag, + frag_properties = [{base_table, Tab}], + ram_copies = [], + disc_copies = [], + disc_only_copies = []}, + + {NewCs2, _, _} = set_frag_nodes(NR, ND, NDO, NewCs, SortedNs, []), + [NewOp] = mnesia_schema:make_create_table(NewCs2), + + SplitOps = split(Tab, FH2, FromIndecies, FragNames, []), + + Cs2 = replace_frag_hash(Cs, FH2), + TabDef = mnesia_schema:cs2list(Cs2), + BaseOp = {op, change_table_frag, {add_frag, SortedNs}, TabDef}, + + [BaseOp, NewOp | SplitOps]. + +replace_frag_hash(Cs, FH) when is_record(FH, frag_state) -> + Fun = fun(Prop) -> + case Prop of + {n_fragments, _} -> + {true, {n_fragments, FH#frag_state.n_fragments}}; + {hash_module, _} -> + {true, {hash_module, FH#frag_state.hash_module}}; + {hash_state, _} -> + {true, {hash_state, FH#frag_state.hash_state}}; + {next_n_to_split, _} -> + false; + {n_doubles, _} -> + false; + _ -> + true + end + end, + Props = lists:zf(Fun, Cs#cstruct.frag_properties), + Cs#cstruct{frag_properties = Props}. + +%% Adjust table info before split +adjust_before_split(FH) -> + HashState = FH#frag_state.hash_state, + {HashState2, FromFrags, AdditionalWriteFrags} = + case FH#frag_state.hash_module of + HashMod when HashMod == ?DEFAULT_HASH_MOD -> + ?DEFAULT_HASH_MOD:add_frag(HashState); + HashMod -> + HashMod:add_frag(HashState) + end, + N = FH#frag_state.n_fragments + 1, + FromFrags2 = (catch lists:sort(FromFrags)), + UnionFrags = (catch lists:merge(FromFrags2, lists:sort(AdditionalWriteFrags))), + VerifyFun = fun(F) when is_integer(F), F >= 1, F =< N -> false; + (_F) -> true + end, + case catch lists:filter(VerifyFun, UnionFrags) of + [] -> + FH2 = FH#frag_state{n_fragments = N, + hash_state = HashState2}, + {FH2, FromFrags2, UnionFrags}; + BadFrags -> + mnesia:abort({"add_frag: Fragment numbers out of range", + BadFrags, {range, 1, N}}) + end. + +split(Tab, FH, [SplitN | SplitNs], FragNames, Ops) -> + SplitFrag = element(SplitN, FragNames), + Pat = mnesia:table_info(SplitFrag, wild_pattern), + {_Mod, Tid, Ts} = mnesia_schema:get_tid_ts_and_lock(Tab, none), + Recs = mnesia:match_object(Tid, Ts, SplitFrag, Pat, read), + Ops2 = do_split(FH, SplitN, FragNames, Recs, Ops), + split(Tab, FH, SplitNs, FragNames, Ops2); +split(_Tab, _FH, [], _FragNames, Ops) -> + Ops. + +%% Perform the split of the table +do_split(FH, OldN, FragNames, [Rec | Recs], Ops) -> + Pos = key_pos(FH), + HashKey = element(Pos, Rec), + case key_to_n(FH, HashKey) of + NewN when NewN == OldN -> + %% Keep record in the same fragment. No need to move it. + do_split(FH, OldN, FragNames, Recs, Ops); + NewN -> + case element(NewN, FragNames) of + NewFrag when NewFrag /= undefined -> + OldFrag = element(OldN, FragNames), + Key = element(2, Rec), + NewOid = {NewFrag, Key}, + OldOid = {OldFrag, Key}, + Ops2 = [{op, rec, unknown, {NewOid, [Rec], write}}, + {op, rec, unknown, {OldOid, [OldOid], delete}} | Ops], + do_split(FH, OldN, FragNames, Recs, Ops2); + _NewFrag -> + %% Tried to move record to fragment that not is locked + mnesia:abort({"add_frag: Fragment not locked", NewN}) + end + end; +do_split(_FH, _OldN, _FragNames, [], Ops) -> + Ops. + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +%% Delete a fragment from a fragmented table +%% and merge its records with an other fragment + +make_multi_del_frag(Tab) -> + verify_multi(Tab), + Ops = make_del_frag(Tab), + + %% Propagate to foreigners + MoreOps = [make_del_frag(T) || T <- lookup_foreigners(Tab)], + [Ops | MoreOps]. + +make_del_frag(Tab) -> + FH = lookup_frag_hash(Tab), + case FH#frag_state.n_fragments of + N when N > 1 -> + Cs = mnesia_schema:incr_version(val({Tab, cstruct})), + mnesia_schema:ensure_active(Cs), + {FH2, FromIndecies, WriteIndecies} = adjust_before_merge(FH), + FragNames = make_frag_names_and_acquire_locks(Tab, N, WriteIndecies, false), + + MergeOps = merge(Tab, FH2, FromIndecies, FragNames, []), + LastFrag = element(N, FragNames), + [LastOp] = mnesia_schema:make_delete_table(LastFrag, single_frag), + Cs2 = replace_frag_hash(Cs, FH2), + TabDef = mnesia_schema:cs2list(Cs2), + BaseOp = {op, change_table_frag, del_frag, TabDef}, + [BaseOp, LastOp | MergeOps]; + _ -> + %% Cannot remove the last fragment + mnesia:abort({no_exists, Tab}) + end. + +%% Adjust tab info before merge +adjust_before_merge(FH) -> + HashState = FH#frag_state.hash_state, + {HashState2, FromFrags, AdditionalWriteFrags} = + case FH#frag_state.hash_module of + HashMod when HashMod == ?DEFAULT_HASH_MOD -> + ?DEFAULT_HASH_MOD:del_frag(HashState); + HashMod -> + HashMod:del_frag(HashState) + end, + N = FH#frag_state.n_fragments, + FromFrags2 = (catch lists:sort(FromFrags)), + UnionFrags = (catch lists:merge(FromFrags2, lists:sort(AdditionalWriteFrags))), + VerifyFun = fun(F) when is_integer(F), F >= 1, F =< N -> false; + (_F) -> true + end, + case catch lists:filter(VerifyFun, UnionFrags) of + [] -> + case lists:member(N, FromFrags2) of + true -> + FH2 = FH#frag_state{n_fragments = N - 1, + hash_state = HashState2}, + {FH2, FromFrags2, UnionFrags}; + false -> + mnesia:abort({"del_frag: Last fragment number not included", N}) + end; + BadFrags -> + mnesia:abort({"del_frag: Fragment numbers out of range", + BadFrags, {range, 1, N}}) + end. + +merge(Tab, FH, [FromN | FromNs], FragNames, Ops) -> + FromFrag = element(FromN, FragNames), + Pat = mnesia:table_info(FromFrag, wild_pattern), + {_Mod, Tid, Ts} = mnesia_schema:get_tid_ts_and_lock(Tab, none), + Recs = mnesia:match_object(Tid, Ts, FromFrag, Pat, read), + Ops2 = do_merge(FH, FromN, FragNames, Recs, Ops), + merge(Tab, FH, FromNs, FragNames, Ops2); +merge(_Tab, _FH, [], _FragNames, Ops) -> + Ops. + +%% Perform the merge of the table +do_merge(FH, OldN, FragNames, [Rec | Recs], Ops) -> + Pos = key_pos(FH), + LastN = FH#frag_state.n_fragments + 1, + HashKey = element(Pos, Rec), + case key_to_n(FH, HashKey) of + NewN when NewN == LastN -> + %% Tried to leave a record in the fragment that is to be deleted + mnesia:abort({"del_frag: Fragment number out of range", + NewN, {range, 1, LastN}}); + NewN when NewN == OldN -> + %% Keep record in the same fragment. No need to move it. + do_merge(FH, OldN, FragNames, Recs, Ops); + NewN when OldN == LastN -> + %% Move record from the fragment that is to be deleted + %% No need to create a delete op for each record. + case element(NewN, FragNames) of + NewFrag when NewFrag /= undefined -> + Key = element(2, Rec), + NewOid = {NewFrag, Key}, + Ops2 = [{op, rec, unknown, {NewOid, [Rec], write}} | Ops], + do_merge(FH, OldN, FragNames, Recs, Ops2); + _NewFrag -> + %% Tried to move record to fragment that not is locked + mnesia:abort({"del_frag: Fragment not locked", NewN}) + end; + NewN -> + case element(NewN, FragNames) of + NewFrag when NewFrag /= undefined -> + OldFrag = element(OldN, FragNames), + Key = element(2, Rec), + NewOid = {NewFrag, Key}, + OldOid = {OldFrag, Key}, + Ops2 = [{op, rec, unknown, {NewOid, [Rec], write}}, + {op, rec, unknown, {OldOid, [OldOid], delete}} | Ops], + do_merge(FH, OldN, FragNames, Recs, Ops2); + _NewFrag -> + %% Tried to move record to fragment that not is locked + mnesia:abort({"del_frag: Fragment not locked", NewN}) + end + end; + do_merge(_FH, _OldN, _FragNames, [], Ops) -> + Ops. + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +%% Add a node to the node pool of a fragmented table + +make_multi_add_node(Tab, Node) -> + verify_multi(Tab), + Ops = make_add_node(Tab, Node), + + %% Propagate to foreigners + MoreOps = [make_add_node(T, Node) || T <- lookup_foreigners(Tab)], + [Ops | MoreOps]. + +make_add_node(Tab, Node) when is_atom(Node) -> + Pool = lookup_prop(Tab, node_pool), + case lists:member(Node, Pool) of + false -> + Cs = mnesia_schema:incr_version(val({Tab, cstruct})), + Pool2 = Pool ++ [Node], + Props = Cs#cstruct.frag_properties, + Props2 = lists:keyreplace(node_pool, 1, Props, {node_pool, Pool2}), + Cs2 = Cs#cstruct{frag_properties = Props2}, + TabDef = mnesia_schema:cs2list(Cs2), + Op = {op, change_table_frag, {add_node, Node}, TabDef}, + [Op]; + true -> + mnesia:abort({already_exists, Tab, Node}) + end; +make_add_node(Tab, Node) -> + mnesia:abort({bad_type, Tab, Node}). + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +%% Delet a node from the node pool of a fragmented table + +make_multi_del_node(Tab, Node) -> + verify_multi(Tab), + Ops = make_del_node(Tab, Node), + + %% Propagate to foreigners + MoreOps = [make_del_node(T, Node) || T <- lookup_foreigners(Tab)], + [Ops | MoreOps]. + +make_del_node(Tab, Node) when is_atom(Node) -> + Cs = mnesia_schema:incr_version(val({Tab, cstruct})), + mnesia_schema:ensure_active(Cs), + Pool = lookup_prop(Tab, node_pool), + case lists:member(Node, Pool) of + true -> + Pool2 = Pool -- [Node], + Props = lists:keyreplace(node_pool, 1, Cs#cstruct.frag_properties, {node_pool, Pool2}), + Cs2 = Cs#cstruct{frag_properties = Props}, + TabDef = mnesia_schema:cs2list(Cs2), + Op = {op, change_table_frag, {del_node, Node}, TabDef}, + [Op]; + false -> + mnesia:abort({no_exists, Tab, Node}) + end; +make_del_node(Tab, Node) -> + mnesia:abort({bad_type, Tab, Node}). + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +%% Special case used to remove all references to a node during +%% mnesia:del_table_copy(schema, Node) + +remove_node(Node, Cs) -> + Tab = Cs#cstruct.name, + case ?catch_val({Tab, frag_hash}) of + {'EXIT', _} -> + {Cs, false}; + _ -> + Pool = lookup_prop(Tab, node_pool), + case lists:member(Node, Pool) of + true -> + Pool2 = Pool -- [Node], + Props = lists:keyreplace(node_pool, 1, + Cs#cstruct.frag_properties, + {node_pool, Pool2}), + {Cs#cstruct{frag_properties = Props}, true}; + false -> + {Cs, false} + end + end. + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +%% Helpers + +val(Var) -> + case ?catch_val(Var) of + {'EXIT', Reason} -> mnesia_lib:other_val(Var, Reason); + Value -> Value + end. + +set_frag_hash(Tab, Props) -> + case props_to_frag_hash(Tab, Props) of + FH when is_record(FH, frag_state) -> + mnesia_lib:set({Tab, frag_hash}, FH); + no_hash -> + mnesia_lib:unset({Tab, frag_hash}) + end. + +props_to_frag_hash(_Tab, []) -> + no_hash; +props_to_frag_hash(Tab, Props) -> + case mnesia_schema:pick(Tab, base_table, Props, undefined) of + T when T == Tab -> + Foreign = mnesia_schema:pick(Tab, foreign_key, Props, must), + N = mnesia_schema:pick(Tab, n_fragments, Props, must), + + case mnesia_schema:pick(Tab, hash_module, Props, undefined) of + undefined -> + Split = mnesia_schema:pick(Tab, next_n_to_split, Props, must), + Doubles = mnesia_schema:pick(Tab, n_doubles, Props, must), + FH = {frag_hash, Foreign, N, Split, Doubles}, + HashState = ?OLD_HASH_MOD:init_state(Tab, FH), + #frag_state{foreign_key = Foreign, + n_fragments = N, + hash_module = ?OLD_HASH_MOD, + hash_state = HashState}; + HashMod -> + HashState = mnesia_schema:pick(Tab, hash_state, Props, must), + #frag_state{foreign_key = Foreign, + n_fragments = N, + hash_module = HashMod, + hash_state = HashState} + %% Old style. Kept for backwards compatibility. + end; + _ -> + no_hash + end. + +lookup_prop(Tab, Prop) -> + Props = val({Tab, frag_properties}), + case lists:keysearch(Prop, 1, Props) of + {value, {Prop, Val}} -> + Val; + false -> + mnesia:abort({no_exists, Tab, Prop, {frag_properties, Props}}) + end. + +lookup_frag_hash(Tab) -> + case ?catch_val({Tab, frag_hash}) of + FH when is_record(FH, frag_state) -> + FH; + {frag_hash, K, N, _S, _D} = FH -> + %% Old style. Kept for backwards compatibility. + HashState = ?OLD_HASH_MOD:init_state(Tab, FH), + #frag_state{foreign_key = K, + n_fragments = N, + hash_module = ?OLD_HASH_MOD, + hash_state = HashState}; + {'EXIT', _} -> + mnesia:abort({no_exists, Tab, frag_properties, frag_hash}) + end. + +%% Returns a list of tables +lookup_foreigners(Tab) -> + %% First field in HashPat is either frag_hash or frag_state + HashPat = {'_', {Tab, '_'}, '_', '_', '_'}, + [T || [T] <- ?ets_match(mnesia_gvar, {{'$1', frag_hash}, HashPat})]. + +%% Returns name of fragment table +record_to_frag_name(Tab, Rec) -> + case ?catch_val({Tab, frag_hash}) of + {'EXIT', _} -> + Tab; + FH -> + Pos = key_pos(FH), + Key = element(Pos, Rec), + N = key_to_n(FH, Key), + n_to_frag_name(Tab, N) + end. + +key_pos(FH) -> + case FH#frag_state.foreign_key of + undefined -> + 2; + {_ForeignTab, Pos} -> + Pos + end. + +%% Returns name of fragment table +key_to_frag_name({BaseTab, _} = Tab, Key) -> + N = key_to_frag_number(Tab, Key), + n_to_frag_name(BaseTab, N); +key_to_frag_name(Tab, Key) -> + N = key_to_frag_number(Tab, Key), + n_to_frag_name(Tab, N). + +%% Returns name of fragment table +n_to_frag_name(Tab, 1) -> + Tab; +n_to_frag_name(Tab, N) when is_atom(Tab), is_integer(N) -> + list_to_atom(atom_to_list(Tab) ++ "_frag" ++ integer_to_list(N)); +n_to_frag_name(Tab, N) -> + mnesia:abort({bad_type, Tab, N}). + +%% Returns name of fragment table +key_to_frag_number({Tab, ForeignKey}, _Key) -> + FH = val({Tab, frag_hash}), + case FH#frag_state.foreign_key of + {_ForeignTab, _Pos} -> + key_to_n(FH, ForeignKey); + undefined -> + mnesia:abort({combine_error, Tab, frag_properties, + {foreign_key, undefined}}) + end; +key_to_frag_number(Tab, Key) -> + case ?catch_val({Tab, frag_hash}) of + {'EXIT', _} -> + 1; + FH -> + key_to_n(FH, Key) + end. + +%% Returns fragment number +key_to_n(FH, Key) -> + HashState = FH#frag_state.hash_state, + N = + case FH#frag_state.hash_module of + HashMod when HashMod == ?DEFAULT_HASH_MOD -> + ?DEFAULT_HASH_MOD:key_to_frag_number(HashState, Key); + HashMod -> + HashMod:key_to_frag_number(HashState, Key) + end, + if + is_integer(N), N >= 1, N =< FH#frag_state.n_fragments -> + N; + true -> + mnesia:abort({"key_to_frag_number: Fragment number out of range", + N, {range, 1, FH#frag_state.n_fragments}}) + end. + +%% Returns a list of frament table names +frag_names(Tab) -> + case ?catch_val({Tab, frag_hash}) of + {'EXIT', _} -> + [Tab]; + FH -> + N = FH#frag_state.n_fragments, + frag_names(Tab, N, []) + end. + +frag_names(Tab, 1, Acc) -> + [Tab | Acc]; +frag_names(Tab, N, Acc) -> + Frag = n_to_frag_name(Tab, N), + frag_names(Tab, N - 1, [Frag | Acc]). + +%% Returns a list of {Node, FragCount} tuples +%% sorted on FragCounts +frag_dist(Tab) -> + Pool = lookup_prop(Tab, node_pool), + Dist = [{good, Node, 0} || Node <- Pool], + Dist2 = count_frag(frag_names(Tab), Dist), + sort_dist(Dist2). + +count_frag([Frag | Frags], Dist) -> + Dist2 = incr_nodes(val({Frag, ram_copies}), Dist), + Dist3 = incr_nodes(val({Frag, disc_copies}), Dist2), + Dist4 = incr_nodes(val({Frag, disc_only_copies}), Dist3), + count_frag(Frags, Dist4); +count_frag([], Dist) -> + Dist. + +incr_nodes([Node | Nodes], Dist) -> + Dist2 = incr_node(Node, Dist), + incr_nodes(Nodes, Dist2); +incr_nodes([], Dist) -> + Dist. + +incr_node(Node, [{Kind, Node, Count} | Tail]) -> + [{Kind, Node, Count + 1} | Tail]; +incr_node(Node, [Head | Tail]) -> + [Head | incr_node(Node, Tail)]; +incr_node(Node, []) -> + [{bad, Node, 1}]. + +%% Sorts dist according in decreasing count order +sort_dist(Dist) -> + Dist2 = deep_dist(Dist, []), + Dist3 = lists:keysort(1, Dist2), + shallow_dist(Dist3). + +deep_dist([Head | Tail], Deep) -> + {Kind, _Node, Count} = Head, + {Tag, Same, Other} = pick_count(Kind, Count, [Head | Tail]), + deep_dist(Other, [{Tag, Same} | Deep]); +deep_dist([], Deep) -> + Deep. + +pick_count(Kind, Count, [{Kind2, Node2, Count2} | Tail]) -> + Head = {Node2, Count2}, + {_, Same, Other} = pick_count(Kind, Count, Tail), + if + Kind == bad -> + {bad, [Head | Same], Other}; + Kind2 == bad -> + {Count, Same, [{Kind2, Node2, Count2} | Other]}; + Count == Count2 -> + {Count, [Head | Same], Other}; + true -> + {Count, Same, [{Kind2, Node2, Count2} | Other]} + end; +pick_count(_Kind, Count, []) -> + {Count, [], []}. + +shallow_dist([{_Tag, Shallow} | Deep]) -> + Shallow ++ shallow_dist(Deep); +shallow_dist([]) -> + []. |