The R13B03 release.OTP_R13B03

1 files changed, 384 insertions, 0 deletions

diff --git a/lib/mnesia/src/mnesia_index.erl b/lib/mnesia/src/mnesia_index.erl
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+++ b/lib/mnesia/src/mnesia_index.erl
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+%%
+%% %CopyrightBegin%
+%% 
+%% Copyright Ericsson AB 1996-2009. 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: Handles index functionality in mnesia
+
+-module(mnesia_index).
+-export([read/5,
+	 add_index/5,
+	 delete_index/3,
+	 del_object_index/5,
+	 clear_index/4,
+	 dirty_match_object/3,
+	 dirty_select/3,
+	 dirty_read/3,
+	 dirty_read2/3,
+
+	 db_put/2,
+	 db_get/2,
+	 db_match_erase/2,
+	 get_index_table/2,
+	 get_index_table/3,
+	 
+	 tab2filename/2,
+	 tab2tmp_filename/2,
+	 init_index/2,
+	 init_indecies/3,
+	 del_transient/2,
+	 del_transient/3,
+	 del_index_table/3]).
+
+-import(mnesia_lib, [verbose/2]).
+-include("mnesia.hrl").
+
+-record(index, {setorbag, pos_list}).
+
+val(Var) ->
+    case ?catch_val(Var) of
+	{'EXIT', _ReASoN_} -> mnesia_lib:other_val(Var, _ReASoN_); 
+	_VaLuE_ -> _VaLuE_ 
+    end.
+
+%% read an object list throuh its index table
+%% we assume that table Tab has index on attribute number Pos
+
+read(Tid, Store, Tab, IxKey, Pos) ->
+    ResList = mnesia_locker:ixrlock(Tid, Store, Tab, IxKey, Pos),
+    %% Remove all tuples which don't include Ixkey, happens when Tab is a bag
+    case val({Tab, setorbag}) of
+	bag -> 
+	    mnesia_lib:key_search_all(IxKey, Pos, ResList);
+	_ -> 
+	    ResList
+    end.
+
+add_index(Index, Tab, Key, Obj, Old) ->    
+    add_index2(Index#index.pos_list, Index#index.setorbag, Tab, Key, Obj, Old).
+
+add_index2([{Pos, Ixt} |Tail], bag, Tab, K, Obj, OldRecs) ->
+    db_put(Ixt, {element(Pos, Obj), K}),
+    add_index2(Tail, bag, Tab, K, Obj, OldRecs);
+add_index2([{Pos, Ixt} |Tail], Type, Tab, K, Obj, OldRecs) ->
+    %% Remove old tuples in index if Tab is updated
+    case OldRecs of 
+	undefined -> 
+	    Old = mnesia_lib:db_get(Tab, K),
+	    del_ixes(Ixt, Old, Pos, K);
+	Old -> 
+	    del_ixes(Ixt, Old, Pos, K)
+    end,
+    db_put(Ixt, {element(Pos, Obj), K}),
+    add_index2(Tail, Type, Tab, K, Obj, OldRecs);
+add_index2([], _, _Tab, _K, _Obj, _) -> ok.
+
+delete_index(Index, Tab, K) ->
+    delete_index2(Index#index.pos_list, Tab, K).
+
+delete_index2([{Pos, Ixt} | Tail], Tab, K) ->
+    DelObjs = mnesia_lib:db_get(Tab, K), 
+    del_ixes(Ixt, DelObjs, Pos, K),
+    delete_index2(Tail, Tab, K);
+delete_index2([], _Tab, _K) -> ok.
+
+
+del_ixes(_Ixt, [], _Pos, _L) -> ok;
+del_ixes(Ixt, [Obj | Tail], Pos, Key) ->
+    db_match_erase(Ixt, {element(Pos, Obj), Key}),
+    del_ixes(Ixt, Tail, Pos, Key).
+
+del_object_index(Index, Tab, K, Obj, Old) ->
+    del_object_index2(Index#index.pos_list, Index#index.setorbag, Tab, K, Obj, Old).
+
+del_object_index2([], _, _Tab, _K, _Obj, _Old) -> ok;
+del_object_index2([{Pos, Ixt} | Tail], SoB, Tab, K, Obj, Old) ->
+    case SoB of
+	bag -> 
+	    del_object_bag(Tab, K, Obj, Pos, Ixt, Old);
+	_ -> %% If set remove the tuple in index table
+	    del_ixes(Ixt, [Obj], Pos, K)	
+    end,
+    del_object_index2(Tail, SoB, Tab, K, Obj, Old).
+
+del_object_bag(Tab, Key, Obj, Pos, Ixt, undefined) -> 
+    IxKey = element(Pos, Obj),
+    Old = [X || X <-  mnesia_lib:db_get(Tab, Key), element(Pos, X) =:= IxKey],
+    del_object_bag(Tab, Key, Obj, Pos, Ixt, Old);
+%% If Tab type is bag we need remove index identifier if Tab 
+%% contains less than 2 elements. 
+del_object_bag(_Tab, Key, Obj, Pos, Ixt, Old) when length(Old) < 2 ->
+    del_ixes(Ixt, [Obj], Pos, Key);
+del_object_bag(_Tab, _Key, _Obj, _Pos, _Ixt, _Old) -> ok.
+
+clear_index(Index, Tab, K, Obj) ->
+    clear_index2(Index#index.pos_list, Tab, K, Obj).
+
+clear_index2([], _Tab, _K, _Obj) -> ok;
+clear_index2([{_Pos, Ixt} | Tail], Tab, K, Obj) ->
+    db_match_erase(Ixt, Obj),
+    clear_index2(Tail, Tab, K, Obj).
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+dirty_match_object(Tab, Pat, Pos) ->
+    %% Assume that we are on the node where the replica is
+    case element(2, Pat) of
+	'_' ->
+	    IxKey = element(Pos, Pat),
+	    RealKeys = realkeys(Tab, Pos, IxKey),
+	    merge(RealKeys, Tab, Pat, []);
+	_Else ->
+	    mnesia_lib:db_match_object(Tab, Pat)
+    end.
+
+merge([{_IxKey, RealKey} | Tail], Tab, Pat, Ack) ->
+    %% Assume that we are on the node where the replica is
+    Pat2 = setelement(2, Pat, RealKey),
+    Recs = mnesia_lib:db_match_object(Tab, Pat2),
+    merge(Tail, Tab, Pat, Recs ++ Ack);
+merge([], _, _, Ack) ->
+    Ack.
+
+realkeys(Tab, Pos, IxKey) ->
+    Index = get_index_table(Tab, Pos),
+    db_get(Index, IxKey). % a list on the form [{IxKey, RealKey1} , ....
+    
+dirty_select(Tab, Spec, Pos) ->
+    %% Assume that we are on the node where the replica is
+    %% Returns the records without applying the match spec
+    %% The actual filtering is handled by the caller
+    IxKey = element(Pos, Spec),
+    RealKeys = realkeys(Tab, Pos, IxKey),
+    StorageType = val({Tab, storage_type}),
+    lists:append([mnesia_lib:db_get(StorageType, Tab, Key) || {_,Key} <- RealKeys]).
+
+dirty_read(Tab, IxKey, Pos) ->
+    ResList = mnesia:dirty_rpc(Tab, ?MODULE, dirty_read2,
+			       [Tab, IxKey, Pos]),
+    case val({Tab, setorbag}) of
+	bag ->
+	    %% Remove all tuples which don't include Ixkey
+	    mnesia_lib:key_search_all(IxKey, Pos, ResList);
+	_ -> 
+	    ResList
+    end.
+
+dirty_read2(Tab, IxKey, Pos) ->
+    Ix = get_index_table(Tab, Pos),
+    Keys = db_match(Ix, {IxKey, '$1'}),
+    r_keys(Keys, Tab, []).
+
+r_keys([[H]|T],Tab,Ack) -> 
+    V = mnesia_lib:db_get(Tab, H),
+    r_keys(T, Tab, V ++ Ack);
+r_keys([], _, Ack) ->
+    Ack.
+	    
+
+%%%%%%% Creation, Init and deletion routines for index tables
+%% We can have several indexes on the same table
+%% this can be a fairly costly operation if table is *very* large
+
+tab2filename(Tab, Pos) ->
+    mnesia_lib:dir(Tab) ++ "_" ++ integer_to_list(Pos) ++ ".DAT".
+
+tab2tmp_filename(Tab, Pos) ->
+    mnesia_lib:dir(Tab) ++ "_" ++ integer_to_list(Pos) ++ ".TMP".
+        
+init_index(Tab, Storage) ->
+    PosList = val({Tab, index}),
+    init_indecies(Tab, Storage, PosList).
+
+init_indecies(Tab, Storage, PosList) ->
+    case Storage of
+	unknown ->
+	    ignore;
+	disc_only_copies ->
+	    init_disc_index(Tab, PosList);
+	ram_copies ->
+	    make_ram_index(Tab, PosList);
+	disc_copies ->
+	    make_ram_index(Tab, PosList)
+    end.
+
+%% works for both ram and disc indexes
+
+del_index_table(_, unknown, _) ->
+    ignore;
+del_index_table(Tab, Storage, Pos) ->
+    delete_transient_index(Tab, Pos, Storage),
+    mnesia_lib:del({Tab, index}, Pos).
+
+del_transient(Tab, Storage) ->
+    PosList = val({Tab, index}),
+    del_transient(Tab, PosList, Storage).
+
+del_transient(_, [], _) -> done;
+del_transient(Tab, [Pos | Tail], Storage) ->
+    delete_transient_index(Tab, Pos, Storage),
+    del_transient(Tab, Tail, Storage).
+
+delete_transient_index(Tab, Pos, disc_only_copies) ->
+    Tag = {Tab, index, Pos},
+    mnesia_monitor:unsafe_close_dets(Tag),
+    file:delete(tab2filename(Tab, Pos)),
+    del_index_info(Tab, Pos), %% Uses val(..)
+    mnesia_lib:unset({Tab, {index, Pos}});
+
+delete_transient_index(Tab, Pos, _Storage) ->
+    Ixt = val({Tab, {index, Pos}}),
+    ?ets_delete_table(Ixt),
+    del_index_info(Tab, Pos),
+    mnesia_lib:unset({Tab, {index, Pos}}).
+
+%%%%% misc functions for the index create/init/delete functions above
+
+%% assuming that the file exists.
+init_disc_index(_Tab, []) ->
+    done;
+init_disc_index(Tab, [Pos | Tail]) when is_integer(Pos) ->
+    Fn = tab2filename(Tab, Pos),
+    IxTag = {Tab, index, Pos},
+    file:delete(Fn),
+    Args = [{file, Fn}, {keypos, 1}, {type, bag}],
+    mnesia_monitor:open_dets(IxTag, Args),
+    Storage = disc_only_copies,
+    Key = mnesia_lib:db_first(Storage, Tab),
+    Recs = mnesia_lib:db_get(Storage, Tab, Key),
+    BinSize = size(term_to_binary(Recs)),
+    KeysPerChunk = (4000 div BinSize) + 1,
+    Init = {start, KeysPerChunk},
+    mnesia_lib:db_fixtable(Storage, Tab, true),
+    ok = dets:init_table(IxTag, create_fun(Init, Tab, Pos)),
+    mnesia_lib:db_fixtable(Storage, Tab, false),
+    mnesia_lib:set({Tab, {index, Pos}}, IxTag),
+    add_index_info(Tab, val({Tab, setorbag}), {Pos, {dets, IxTag}}),
+    init_disc_index(Tab, Tail).
+
+create_fun(Cont, Tab, Pos) ->
+    fun(read) ->
+	    Data = 
+		case Cont of
+		    {start, KeysPerChunk} ->
+			mnesia_lib:db_init_chunk(disc_only_copies, Tab, KeysPerChunk);
+		    '$end_of_table' -> 
+			'$end_of_table';
+		    _Else ->
+			mnesia_lib:db_chunk(disc_only_copies, Cont)
+		end,
+	    case Data of
+		'$end_of_table' ->
+		    end_of_input;
+		{Recs, Next} ->
+		    IdxElems = [{element(Pos, Obj), element(2, Obj)} || Obj <- Recs],
+		    {IdxElems, create_fun(Next, Tab, Pos)}
+	    end;
+       (close) ->
+	    ok
+    end.
+
+make_ram_index(_, []) -> 
+    done;
+make_ram_index(Tab, [Pos | Tail]) ->
+    add_ram_index(Tab, Pos),
+    make_ram_index(Tab, Tail).
+
+add_ram_index(Tab, Pos) when is_integer(Pos) ->
+    verbose("Creating index for ~w ~n", [Tab]),
+    Index = mnesia_monitor:mktab(mnesia_index, [bag, public]),
+    Insert = fun(Rec, _Acc) ->
+		     true = ?ets_insert(Index, {element(Pos, Rec), element(2, Rec)})
+	     end,
+    mnesia_lib:db_fixtable(ram_copies, Tab, true),
+    true = ets:foldl(Insert, true, Tab),
+    mnesia_lib:db_fixtable(ram_copies, Tab, false),
+    mnesia_lib:set({Tab, {index, Pos}}, Index),
+    add_index_info(Tab, val({Tab, setorbag}), {Pos, {ram, Index}});
+add_ram_index(_Tab, snmp) ->
+    ok.
+
+add_index_info(Tab, Type, IxElem) ->
+    Commit = val({Tab, commit_work}),
+    case lists:keysearch(index, 1, Commit) of
+	false ->
+	    Index = #index{setorbag = Type, 
+			   pos_list = [IxElem]},
+	    %% Check later if mnesia_tm is sensative about the order 
+	    mnesia_lib:set({Tab, commit_work}, 
+			   mnesia_lib:sort_commit([Index | Commit]));
+	{value, Old} ->
+	    %% We could check for consistency here
+	    Index = Old#index{pos_list = [IxElem | Old#index.pos_list]},
+	    NewC = lists:keyreplace(index, 1, Commit, Index),
+	    mnesia_lib:set({Tab, commit_work}, 
+			   mnesia_lib:sort_commit(NewC))
+    end.
+
+del_index_info(Tab, Pos) ->
+    Commit = val({Tab, commit_work}),
+    case lists:keysearch(index, 1, Commit) of
+	false ->
+	    %% Something is wrong ignore
+	    skip;
+	{value, Old} ->
+	    case lists:keydelete(Pos, 1, Old#index.pos_list) of
+		[] -> 
+		    NewC = lists:keydelete(index, 1, Commit),
+		    mnesia_lib:set({Tab, commit_work}, 
+				   mnesia_lib:sort_commit(NewC));
+		New ->
+		    Index = Old#index{pos_list = New},
+		    NewC = lists:keyreplace(index, 1, Commit, Index),
+		    mnesia_lib:set({Tab, commit_work}, 
+				   mnesia_lib:sort_commit(NewC))
+	    end
+    end.
+
+db_put({ram, Ixt}, V) ->
+    true = ?ets_insert(Ixt, V);
+db_put({dets, Ixt}, V) ->
+    ok = dets:insert(Ixt, V).
+
+db_get({ram, Ixt}, K) ->
+    ?ets_lookup(Ixt, K);
+db_get({dets, Ixt}, K) ->
+    dets:lookup(Ixt, K).
+
+db_match_erase({ram, Ixt}, Pat) ->
+    true = ?ets_match_delete(Ixt, Pat);
+db_match_erase({dets, Ixt}, Pat) ->
+    ok = dets:match_delete(Ixt, Pat).
+    
+db_match({ram, Ixt}, Pat) ->
+    ?ets_match(Ixt, Pat);
+db_match({dets, Ixt}, Pat) ->
+    dets:match(Ixt, Pat).
+    
+get_index_table(Tab, Pos) ->
+    get_index_table(Tab,  val({Tab, storage_type}), Pos).
+
+get_index_table(Tab, ram_copies, Pos) ->
+    {ram,  val({Tab, {index, Pos}})};
+get_index_table(Tab, disc_copies, Pos) ->
+    {ram,  val({Tab, {index, Pos}})};
+get_index_table(Tab, disc_only_copies, Pos) ->
+    {dets, val({Tab, {index, Pos}})};
+get_index_table(_Tab, unknown, _Pos) ->
+    unknown.
+