Merge branch 'aronisstav/dialyzer/dialyzer_tests/OTP-9116' into dev

* aronisstav/dialyzer/dialyzer_tests/OTP-9116:
  Increase timetrap of options1 suite
  Write output_plt even when plt_check is ok
  Create plt with erts, kernel and stdlib only
  Update test results as they currently appear in dev
  Major restructure of dialyzer's testsuite
  Add 'apps' option to the erlang interface
  Update spec file to work with new common test structure
  Test suites for Dialyzer

1 files changed, 1201 insertions, 0 deletions

diff --git a/lib/dialyzer/test/r9c_tests_SUITE_data/src/mnesia/mnesia_frag.erl b/lib/dialyzer/test/r9c_tests_SUITE_data/src/mnesia/mnesia_frag.erl
new file mode 100644
index 0000000000..e1f4e96a95
--- /dev/null
+++ b/lib/dialyzer/test/r9c_tests_SUITE_data/src/mnesia/mnesia_frag.erl
@@ -0,0 +1,1201 @@
+%%% ``The contents of this file are subject to the Erlang Public License,
+%%% Version 1.1, (the "License"); you may not use this file except in
+%%% compliance with the License. You should have received a copy of the
+%%% Erlang Public License along with this software. If not, it can be
+%%% retrieved via the world wide web at http://www.erlang.org/.
+%%% 
+%%% Software distributed under the License is distributed on an "AS IS"
+%%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+%%% the License for the specific language governing rights and limitations
+%%% under the License.
+%%% 
+%%% The Initial Developer of the Original Code is Ericsson Utvecklings AB.
+%%% Portions created by Ericsson are Copyright 1999, Ericsson Utvecklings
+%%% AB. All Rights Reserved.''
+%%% 
+%%%     $Id: mnesia_frag.erl,v 1.1 2008/12/17 09:53:38 mikpe Exp $
+%%%
+%%%----------------------------------------------------------------------
+%%% Purpose : Support tables so large that they need
+%%%           to be divided into several fragments.
+%%%----------------------------------------------------------------------
+
+%header_doc_include
+
+-module(mnesia_frag).
+-behaviour(mnesia_access).
+
+%% 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,
+	 index_match_object/6, index_read/6,
+	 foldl/6, foldr/6,
+	 table_info/4
+       ]).
+
+%header_doc_include
+
+-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).
+
+all_keys(ActivityId, Opaque, Tab, LockKind) ->
+    Match = [mnesia:all_keys(ActivityId, Opaque, Frag, LockKind)
+	     || Frag <- frag_names(Tab)],
+    lists:append(Match).
+
+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.
+%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.
+
+do_select(ActivityId, Opaque, Tab, MatchSpec, LockKind) ->
+    case ?catch_val({Tab, frag_hash}) of
+	{'EXIT', _} ->
+	    mnesia:select(ActivityId, Opaque, Tab, MatchSpec, LockKind);
+	FH ->
+	    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 integer(F), F >= 1, F =< N -> false;
+			   (_F) -> true
+			end,
+	    case catch lists:filter(VerifyFun, FragNumbers) of
+		[] ->
+		    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 ->
+			    SelectFun =
+				fun(PatchedMatchSpec) ->
+					Ref = make_ref(),
+					Args = [self(), Ref, RemoteNameNodes, PatchedMatchSpec],
+					Pid = spawn_link(?MODULE, local_select, Args),
+					LocalMatch = [mnesia:dirty_select(Name, PatchedMatchSpec)
+						      || {Name, Node} <- NameNodes, Node == node()],
+					OldSelectFun = fun() -> SelectAllFun(PatchedMatchSpec) end,
+					local_collect(Ref, Pid, lists:append(LocalMatch), OldSelectFun)
+				end,
+			    mnesia:fun_select(ActivityId, Opaque, Tab, MatchSpec, none, '_', SelectFun)
+		    end;
+		BadFrags ->
+		    mnesia:abort({"match_spec_to_frag_numbers: Fragment numbers out of range",
+				  BadFrags, {range, 1, N}})
+	    end
+    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, LocalMatch, OldSelectFun) ->
+    receive
+	{local_select, Ref, LocalRes} ->
+	    remote_collect(Ref, LocalRes, LocalMatch, OldSelectFun);
+	{'EXIT', Pid, Reason} ->
+	    remote_collect(Ref, {error, Reason}, [], OldSelectFun)
+    end.
+    
+remote_collect(Ref, LocalRes = ok, Acc, OldSelectFun) ->
+    receive
+	{remote_select, Ref, Node, RemoteRes} ->
+	    case RemoteRes of
+		{ok, RemoteMatch} ->
+		    remote_collect(Ref, LocalRes, RemoteMatch ++ Acc, OldSelectFun);
+		_ ->
+		    remote_collect(Ref, {error, {node_not_running, Node}}, [], OldSelectFun)
+	    end
+    after 0 ->
+	    Acc
+    end;
+remote_collect(Ref, LocalRes = {error, Reason}, _Acc, OldSelectFun) ->
+    receive
+	{remote_select, Ref, _Node, _RemoteRes} ->
+	    remote_collect(Ref, 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 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 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 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 atom(N), integer(Count), Count >= 0 ->
+		{N, Count + 1};
+	    N when atom(N) ->
+		{N, 1};
+	    BadNode ->
+		mnesia:abort({bad_type, Cs#cstruct.name, BadNode})
+	end,
+    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 atom(Node2), 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 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 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 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 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 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 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 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 is_top_frag(Tab) of
+	false ->
+	    {Cs, false};
+	true -> 
+	    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 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 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.
+
+is_top_frag(Tab) ->
+    case ?catch_val({Tab, frag_hash}) of
+	{'EXIT', _} ->
+	    false;
+	_ -> 
+	    [] == lookup_foreigners(Tab)
+    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 atom(Tab), 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
+	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([]) ->
+    [].