Use new on-disk page format

This updates moves from kvlist to on-disk bisect
format (https://github.com/krestenkrab/vbisect)
which means that tree pages are not deserialised
when read form disk.  This improves performance
of GETs by ~20% and improves top-level latencies
significantly.

CRC32 checks are now on the page level.

src/hanoidb.hrl

@@ -82,3 +82,13 @@
 -define(BLOOM_INSERT(Bloom, Key),   hanoidb_util:bloom_insert(Bloom, Key)).
 -define(BLOOM_CONTAINS(Bloom, Key), hanoidb_util:bloom_contains(Bloom, Key)).
 
+%% tags used in the on-disk representation
+-define(TAG_KV_DATA,  16#80).
+-define(TAG_DELETED,  16#81).
+-define(TAG_POSLEN32, 16#82).
+-define(TAG_TRANSACT, 16#83).
+-define(TAG_KV_DATA2, 16#84).
+-define(TAG_DELETED2, 16#85).
+-define(TAG_END,      16#FF).
+
+

src/hanoidb_merger.erl

@@ -69,12 +69,12 @@ merge(A,B,C, Size, IsLastLevel, Options) ->
     {ok, Out} = hanoidb_writer:init([C, [{size, Size} | Options]]),
     AKVs =
         case hanoidb_reader:first_node(IXA) of
-            {node, AKV} -> AKV;
+            {kvlist, AKV} -> AKV;
             none -> []
         end,
     BKVs =
         case hanoidb_reader:first_node(IXB) of
-            {node, BKV} ->BKV;
+            {kvlist, BKV} ->BKV;
             none -> []
         end,
     scan(IXA, IXB, Out, IsLastLevel, AKVs, BKVs, {0, none}).
@@ -177,7 +177,7 @@ scan(IXA, IXB, Out, IsLastLevel, AKVs, BKVs, {N, FromPID}) when N < 1, AKVs =/=
 
 scan(IXA, IXB, Out, IsLastLevel, [], BKVs, Step) ->
     case hanoidb_reader:next_node(IXA) of
-        {node, AKVs} ->
+        {kvlist, AKVs} ->
             scan(IXA, IXB, Out, IsLastLevel, AKVs, BKVs, Step);
         end_of_data ->
             hanoidb_reader:close(IXA),
@@ -186,7 +186,7 @@ scan(IXA, IXB, Out, IsLastLevel, [], BKVs, Step) ->
 
 scan(IXA, IXB, Out, IsLastLevel, AKVs, [], Step) ->
     case hanoidb_reader:next_node(IXB) of
-        {node, BKVs} ->
+        {kvlist, BKVs} ->
             scan(IXA, IXB, Out, IsLastLevel, AKVs, BKVs, Step);
         end_of_data ->
             hanoidb_reader:close(IXB),
@@ -248,7 +248,7 @@ scan_only(IX, Out, IsLastLevel, KVs, {N, FromPID}) when N < 1, KVs =/= [] ->
 
 scan_only(IX, Out, IsLastLevel, [], {_, FromPID}=Step) ->
     case hanoidb_reader:next_node(IX) of
-        {node, KVs} ->
+        {kvlist, KVs} ->
             scan_only(IX, Out, IsLastLevel, KVs, Step);
         end_of_data ->
             case FromPID of

src/hanoidb_reader.erl

@@ -37,24 +37,23 @@
 -export([serialize/1, deserialize/1]).
 
 -record(node, {level       :: non_neg_integer(),
-               members=[]  :: list(any()) }).
+               members=[]  :: list(any()) | binary() }).
 
 -record(index, {file       :: file:io_device(),
-                root       :: #node{} | none,
+                root= none :: #node{} | none,
                 bloom      :: term(),
                 name       :: string(),
                 config=[]  :: term() }).
 
 -type read_file() :: #index{}.
+-export_type([read_file/0]).
 
 -spec open(Name::string()) -> {ok, read_file()} | {error, any()}.
 open(Name) ->
     open(Name, [random]).
 
 -type config() :: [sequential | folding | random | {atom(), term()}].
-
 -spec open(Name::string(), config()) -> {ok, read_file()}  | {error, any()}.
-
 open(Name, Config) ->
     case proplists:get_bool(sequential, Config) of
         true ->
@@ -115,11 +114,15 @@ deserialize({seq_read_file, Index, Position}) ->
 
 
 
+
 fold(Fun, Acc0, #index{file=File}) ->
     {ok, Node} = read_node(File,?FIRST_BLOCK_POS),
     fold0(File,fun({K,V},Acc) -> Fun(K,V,Acc) end,Node,Acc0).
 
-fold0(File,Fun,#node{level=0, members=List},Acc0) ->
+fold0(File,Fun,#node{level=0, members=BinPage},Acc0) when is_binary(BinPage) ->
+    Acc1 = vbisect:foldl(fun(K, V, Acc2) -> Fun({K, decode_binary_value(V)}, Acc2) end,Acc0,BinPage),
+    fold1(File,Fun,Acc1);
+fold0(File,Fun,#node{level=0, members=List},Acc0) when is_list(List) ->
     Acc1 = lists:foldl(Fun,Acc0,List),
     fold1(File,Fun,Acc1);
 fold0(File,Fun,_InnerNode,Acc0) ->
@@ -133,22 +136,39 @@ fold1(File,Fun,Acc0) ->
             fold0(File,Fun,Node,Acc0)
     end.
 
--spec range_fold(function(), any(), #index{}, #key_range{}) ->
+-spec range_fold(fun((binary(),binary(),any()) -> any()), any(), #index{}, #key_range{}) ->
                         {limit, any(), binary()} | {done, any()}.
 range_fold(Fun, Acc0, #index{file=File,root=Root}, Range) ->
-    case lookup_node(File,Range#key_range.from_key,Root,?FIRST_BLOCK_POS) of
+    case Range#key_range.from_key =< first_key(Root) of
-        {ok, {Pos,_}} ->
+        true ->
-            {ok, _} = file:position(File, Pos),
+            {ok, _} = file:position(File, ?FIRST_BLOCK_POS),
-            do_range_fold(Fun, Acc0, File, Range, Range#key_range.limit);
+            range_fold_from_here(Fun, Acc0, File, Range, Range#key_range.limit);
-        {ok, Pos} ->
+        false ->
-            {ok, _} = file:position(File, Pos),
+            case find_leaf_node(File,Range#key_range.from_key,Root,?FIRST_BLOCK_POS) of
-            do_range_fold(Fun, Acc0, File, Range, Range#key_range.limit);
+                {ok, {Pos,_}} ->
-        none ->
+                    {ok, _} = file:position(File, Pos),
-            {done, Acc0}
+                    range_fold_from_here(Fun, Acc0, File, Range, Range#key_range.limit);
+                {ok, Pos} ->
+                    {ok, _} = file:position(File, Pos),
+                    range_fold_from_here(Fun, Acc0, File, Range, Range#key_range.limit);
+                none ->
+                    {done, Acc0}
+            end
     end.
 
-fold_until_stop(Fun,Acc,List) ->
+first_key(#node{members=Dict}) ->
-    fold_until_stop2(Fun, {continue, Acc}, List).
+    {_,FirstKey} = fold_until_stop(fun({K,_},_) -> {stop, K} end, none, Dict),
+    FirstKey.
+
+fold_until_stop(Fun,Acc,List) when is_list(List) ->
+    fold_until_stop2(Fun, {continue, Acc}, List);
+fold_until_stop(Fun,Acc0,Bin) when is_binary(Bin) ->
+    vbisect:fold_until_stop(fun({Key,VBin},Acc1) ->
+%                                    io:format("-> DOING ~p,~p~n", [Key,Acc1]),
+                                    Fun({Key, decode_binary_value(VBin)}, Acc1)
+                            end,
+                            Acc0,
+                            Bin).
 
 fold_until_stop2(_Fun,{stop,Result},_) ->
     {stopped, Result};
@@ -170,7 +190,8 @@ get_value({Value, _TStamp}) ->
 get_value(Value) ->
     Value.
 
-do_range_fold(Fun, Acc0, File, Range, undefined) ->
+range_fold_from_here(Fun, Acc0, File, Range, undefined) ->
+%    io:format("RANGE_FOLD_FROM_HERE(~p,~p)~n", [Acc0,File]),
     case next_leaf_node(File) of
         eof ->
             {done, Acc0};
@@ -185,18 +206,19 @@ do_range_fold(Fun, Acc0, File, Range, undefined) ->
                                              false ->
                                                  {continue, Fun(Key, get_value(Value), Acc)}
                                          end;
-                                    (_, Acc) ->
+                                    (_Huh, Acc) ->
+%                                         io:format("SKIPPING ~p~n", [_Huh]),
                                          {continue, Acc}
                                  end,
                                  Acc0,
                                  Members) of
                 {stopped, Result} -> Result;
                 {ok, Acc1} ->
-                    do_range_fold(Fun, Acc1, File, Range, undefined)
+                    range_fold_from_here(Fun, Acc1, File, Range, undefined)
             end
     end;
 
-do_range_fold(Fun, Acc0, File, Range, N0) ->
+range_fold_from_here(Fun, Acc0, File, Range, N0) ->
     case next_leaf_node(File) of
         eof ->
             {done, Acc0};
@@ -226,52 +248,74 @@ do_range_fold(Fun, Acc0, File, Range, N0) ->
                                          {continue, Acc}
                                  end,
                                  {N0, Acc0},
-                                 Members) of
+                                 Members)
-                {stopped, Result} -> Result;
+             of
+                {stopped, Result} ->
+                    Result;
                 {ok, {N2, Acc1}} ->
-                    do_range_fold(Fun, Acc1, File, Range, N2)
+                    range_fold_from_here(Fun, Acc1, File, Range, N2)
             end
     end.
 
-lookup_node(_File,_FromKey,#node{level=0},Pos) ->
+find_leaf_node(_File,_FromKey,#node{level=0},Pos) ->
     {ok, Pos};
-lookup_node(File,FromKey,#node{members=Members,level=N},_) ->
+find_leaf_node(File,FromKey,#node{members=Members,level=N},_) when is_list(Members) ->
     case find_start(FromKey, Members) of
-        {ok, ChildPos} when N==1 ->
-            {ok, ChildPos};
         {ok, ChildPos} ->
-            case read_node(File,ChildPos) of
+            recursive_find(File, FromKey, N, ChildPos);
-                {ok, ChildNode} ->
-                    lookup_node(File,FromKey,ChildNode,ChildPos);
-                eof ->
-                    none
-            end;
         not_found ->
             none
     end;
-lookup_node(_,_,none,_) ->
+find_leaf_node(File,FromKey,#node{members=Members,level=N},_) when is_binary(Members) ->
+    case vbisect:find_geq(FromKey,Members) of
+        {ok, _, <<?TAG_POSLEN32, Pos:64/unsigned, Len:32/unsigned>>} ->
+%            io:format("** FIND_LEAF_NODE(~p,~p) -> {~p,~p}~n", [FromKey, N, Pos,Len]),
+            recursive_find(File, FromKey, N, {Pos,Len});
+        none ->
+%            io:format("** FIND_LEAF_NODE(~p,~p) -> none~n", [FromKey, N]),
+            none
+    end;
+find_leaf_node(_,_,none,_) ->
     none.
 
+recursive_find(_File,_FromKey,1,ChildPos) ->
+    {ok, ChildPos};
+recursive_find(File,FromKey,N,ChildPos) when N>1 ->
+    case read_node(File,ChildPos) of
+        {ok, ChildNode} ->
+            find_leaf_node(File, FromKey,ChildNode,ChildPos);
+        eof ->
+            none
+    end.
 
 
+%% used by the merger, needs list value
 first_node(#index{file=File}) ->
     case read_node(File, ?FIRST_BLOCK_POS) of
         {ok, #node{level=0, members=Members}} ->
-            {node, Members};
+            {kvlist, decode_member_list(Members)};
         eof->
             none
     end.
 
+%% used by the merger, needs list value
 next_node(#index{file=File}=_Index) ->
     case next_leaf_node(File) of
         {ok, #node{level=0, members=Members}} ->
-            {node, Members};
+            {kvlist, decode_member_list(Members)};
-%        {ok, #node{level=N}} when N>0 ->
-%            next_node(Index);
         eof ->
             end_of_data
     end.
 
+decode_member_list(List) when is_list(List) ->
+    List;
+decode_member_list(BinDict) when is_binary(BinDict) ->
+    vbisect:foldr( fun(Key,Value,Acc) ->
+                           [{Key, decode_binary_value(Value) }|Acc]
+                   end,
+                   [],
+                   BinDict).
+
 close(#index{file=undefined}) ->
     ok;
 close(#index{file=File}) ->
@@ -297,11 +341,20 @@ lookup(#index{file=File, root=Node, bloom=Bloom}, Key) ->
     end.
 
 lookup_in_node(_File,#node{level=0,members=Members}, Key) ->
-    case lists:keyfind(Key,1,Members) of
+    find_in_leaf(Key,Members);
-        false ->
+
-            not_found;
+lookup_in_node(File,#node{members=Members},Key) when is_binary(Members) ->
-        {_,Value} ->
+    case vbisect:find_geq(Key,Members) of
-            {ok, Value}
+        {ok, _Key, <<?TAG_POSLEN32, Pos:64, Size:32>>} ->
+%            io:format("FOUND ~p @ ~p~n", [_Key, {Pos,Size}]),
+            case read_node(File,{Pos,Size}) of
+                {ok, Node} ->
+                    lookup_in_node(File, Node, Key);
+                eof ->
+                    not_found
+            end;
+        none ->
+            not_found
     end;
 
 lookup_in_node(File,#node{members=Members},Key) ->
@@ -416,3 +469,29 @@ next_leaf_node(File) ->
             next_leaf_node(File)
     end.
 
+
+find_in_leaf(Key,Bin) when is_binary(Bin) ->
+    case vbisect:find(Key,Bin) of
+        {ok, BinValue} ->
+            {ok, decode_binary_value(BinValue)};
+        error ->
+            not_found
+    end;
+find_in_leaf(Key,List) when is_list(List) ->
+    case lists:keyfind(Key, 1, List) of
+        {_, Value} ->
+            {ok, Value};
+        false ->
+            not_found
+    end.
+
+decode_binary_value(<<?TAG_KV_DATA, Value/binary>>) ->
+    Value;
+decode_binary_value(<<?TAG_KV_DATA2, TStamp:32, Value/binary>>) ->
+    {Value, TStamp};
+decode_binary_value(<<?TAG_DELETED>>) ->
+    ?TOMBSTONE;
+decode_binary_value(<<?TAG_DELETED2, TStamp:32>>) ->
+    {?TOMBSTONE, TStamp};
+decode_binary_value(<<?TAG_POSLEN32, Pos:64, Len:32>>) ->
+    {Pos, Len}.

src/hanoidb_util.erl

@@ -53,14 +53,10 @@
 
 -define(ERLANG_ENCODED,  131).
 -define(CRC_ENCODED,     127).
+-define(BISECT_ENCODED,  126).
 
--define(TAG_KV_DATA,  16#80).
+
--define(TAG_DELETED,  16#81).
+-define(FILE_ENCODING, bisect).
--define(TAG_POSLEN32, 16#82).
--define(TAG_TRANSACT, 16#83).
--define(TAG_KV_DATA2, 16#84).
--define(TAG_DELETED2, 16#85).
--define(TAG_END,      16#FF).
 
 -compile({inline, [crc_encapsulate/1, crc_encapsulate_kv_entry/2 ]}).
 
@@ -143,18 +139,47 @@ uncompress(<<?GZIP_COMPRESSION, Data/binary>>) ->
     zlib:gunzip(Data).
 
 encode_index_node(KVList, Method) ->
-    TermData = [ ?TAG_END |
+    TermData =
-                 lists:map(fun ({Key,Value}) ->
+    case ?FILE_ENCODING of
-                                   crc_encapsulate_kv_entry(Key, Value)
+        bisect ->
-                           end,
+            Binary = vbisect:from_orddict(lists:map(fun binary_encode_kv/1, KVList)),
-                           KVList) ],
+            CRC = erlang:crc32(Binary),
+            [?BISECT_ENCODED, <<CRC:32>>, Binary];
+        hanoi2 ->
+            [ ?TAG_END |
+              lists:map(fun ({Key,Value}) ->
+                                crc_encapsulate_kv_entry(Key, Value)
+                        end,
+                        KVList) ]
+    end,
     {MethodName, OutData} = compress(Method, TermData),
     {ok, [MethodName | OutData]}.
 
 decode_index_node(Level, Data) ->
     TermData = uncompress(Data),
-    {ok, KVList} = decode_kv_list(TermData),
+    case decode_kv_list(TermData) of
-    {ok, {node, Level, KVList}}.
+        {ok, KVList} ->
+            {ok, {node, Level, KVList}};
+        {bisect, Binary} ->
+%            io:format("[page level=~p~n", [Level]),
+%            vbisect:foldl(fun(K,V,_) -> io:format(" ~p -> ~p,~n", [K,V]) end, 0, Binary),
+%            io:format("]~n",[]),
+            {ok, {node, Level, Binary}}
+    end.
+
+
+binary_encode_kv({Key, {Value,infinity}}) ->
+    binary_encode_kv({Key,Value});
+binary_encode_kv({Key, {?TOMBSTONE, TStamp}}) ->
+    {Key, <<?TAG_DELETED2, TStamp:32>>};
+binary_encode_kv({Key, ?TOMBSTONE}) ->
+    {Key, <<?TAG_DELETED>>};
+binary_encode_kv({Key, {Value, TStamp}}) when is_binary(Value) ->
+    {Key, <<?TAG_KV_DATA2, TStamp:32, Value/binary>>};
+binary_encode_kv({Key, Value}) when is_binary(Value)->
+    {Key, <<?TAG_KV_DATA, Value/binary>>};
+binary_encode_kv({Key, {Pos, Len}}) when Len < 16#ffffffff ->
+    {Key, <<?TAG_POSLEN32, Pos:64/unsigned, Len:32/unsigned>>}.
 
 
 -spec crc_encapsulate_kv_entry(binary(), expvalue()) -> iolist().
@@ -193,7 +218,14 @@ decode_kv_list(<<?TAG_END, Custom/binary>>) ->
 decode_kv_list(<<?ERLANG_ENCODED, _/binary>>=TermData) ->
     {ok, erlang:term_to_binary(TermData)};
 decode_kv_list(<<?CRC_ENCODED, Custom/binary>>) ->
-    decode_crc_data(Custom, [], []).
+    decode_crc_data(Custom, [], []);
+decode_kv_list(<<?BISECT_ENCODED, CRC:32/unsigned, Binary/binary>>) ->
+    CRCTest = erlang:crc32( Binary ),
+    if CRC == CRCTest ->
+            {bisect, Binary};
+       true ->
+            {bisect, vbisect:from_orddict([])}
+    end.
 
 -spec decode_crc_data(binary(), list(), list()) -> {ok, [kventry()]} | {partial, [kventry()], iolist()}.
 decode_crc_data(<<>>, [], Acc) ->

src/vbisect.erl

@@ -0,0 +1,260 @@
+
+
+-module(vbisect).
+
+-export([from_orddict/1,
+         from_gb_tree/1,
+         to_gb_tree/1,
+         first_key/1,
+         find/2, find_geq/2,
+         foldl/3, foldr/3, fold_until_stop/3,
+         to_orddict/1,
+         merge/3]).
+
+-define(MAGIC, "vbis").
+-type key() :: binary().
+-type value() :: binary().
+-type bindict() :: binary().
+
+-ifdef(TEST).
+-include_lib("eunit/include/eunit.hrl").
+-endif.
+
+-spec from_gb_tree(gb_trees:tree()) -> bindict().
+from_gb_tree({Count,Node}) when Count =< 16#ffffffff ->
+    {_BinSize,IOList} = encode_gb_node(Node),
+    erlang:iolist_to_binary([ <<?MAGIC,  Count:32/unsigned >> | IOList ]).
+
+encode_gb_node({Key, Value, Smaller, Bigger}) when is_binary(Key), is_binary(Value) ->
+    {BinSizeSmaller, IOSmaller} = encode_gb_node(Smaller),
+    {BinSizeBigger, IOBigger} = encode_gb_node(Bigger),
+
+    KeySize = byte_size(Key),
+    ValueSize = byte_size(Value),
+    { 2 + KeySize
+      + 4 + ValueSize
+      + 4 + BinSizeSmaller
+      + BinSizeBigger,
+
+      [ << KeySize:16, Key/binary,
+           BinSizeSmaller:32 >>, IOSmaller,
+        << ValueSize:32, Value/binary >> | IOBigger ] };
+
+encode_gb_node(nil) ->
+    { 0, [] }.
+
+to_gb_tree(<<?MAGIC,  Count:32, Nodes/binary >>) ->
+    { Count, to_gb_node(Nodes) }.
+
+to_gb_node( <<>> ) ->
+    nil;
+
+to_gb_node( << KeySize:16, Key:KeySize/binary,
+               BinSizeSmaller:32, Smaller:BinSizeSmaller/binary,
+               ValueSize:32, Value:ValueSize/binary,
+               Bigger/binary >> ) ->
+    {Key, Value,
+     to_gb_node(Smaller),
+     to_gb_node(Bigger)}.
+
+-spec find(Key::key(), Dict::bindict()) ->
+                  { ok, value() } | error.
+find(Key, <<?MAGIC, _:32, Binary/binary>>) ->
+    find_node(byte_size(Key), Key, Binary).
+
+find_node(KeySize, Key, <<HereKeySize:16, HereKey:HereKeySize/binary,
+                          BinSizeSmaller:32, _:BinSizeSmaller/binary,
+                          ValueSize:32, Value:ValueSize/binary,
+                          _/binary>> = Bin) ->
+    if
+        Key < HereKey ->
+            Skip = 6 + HereKeySize,
+            << _:Skip/binary, Smaller:BinSizeSmaller/binary, _/binary>> = Bin,
+            find_node(KeySize, Key, Smaller);
+        HereKey < Key ->
+            Skip = 10 + HereKeySize + BinSizeSmaller + ValueSize,
+            << _:Skip/binary, Bigger/binary>> = Bin,
+            find_node(KeySize, Key, Bigger);
+        true ->
+            {ok, Value}
+    end;
+
+find_node(_, _, <<>>) ->
+    error.
+
+to_orddict(BinDict) ->
+    foldr(fun(Key,Value,Acc) ->
+                  [{Key,Value}|Acc]
+          end,
+          [],
+          BinDict).
+
+merge(Fun, BinDict1, BinDict2) ->
+    OD1 = to_orddict(BinDict1),
+    OD2 = to_orddict(BinDict2),
+    OD3 = orddict:merge(Fun, OD1, OD2),
+    from_orddict(OD3).
+
+-spec first_key( bindict() ) -> binary() | none.
+first_key(BinDict) ->
+    {_, Key} = fold_until_stop(fun({K,_},_) -> {stop, K} end, none, BinDict),
+    Key.
+
+%% @doc Find largest {K,V} where K is smaller than or equal to key.
+%% This is good for an inner node where key is the smallest key
+%% in the child node.
+
+-spec find_geq(Key::binary(), Binary::binary()) ->
+                      none | {ok, Key::key(), Value::value()}.
+
+find_geq(Key, <<?MAGIC, _:32, Binary/binary>>) ->
+    find_geq_node(byte_size(Key), Key, Binary, none).
+
+find_geq_node(_, _, <<>>, Else) ->
+    Else;
+
+find_geq_node(KeySize, Key, <<HereKeySize:16, HereKey:HereKeySize/binary,
+                              BinSizeSmaller:32, _:BinSizeSmaller/binary,
+                              ValueSize:32, Value:ValueSize/binary,
+                              _/binary>> = Bin, Else) ->
+    if
+        Key < HereKey ->
+            Skip = 6 + HereKeySize,
+            << _:Skip/binary, Smaller:BinSizeSmaller/binary, _/binary>> = Bin,
+            find_geq_node(KeySize, Key, Smaller, Else);
+        HereKey < Key ->
+            Skip = 10 + HereKeySize + BinSizeSmaller + ValueSize,
+            << _:Skip/binary, Bigger/binary>> = Bin,
+            find_geq_node(KeySize, Key, Bigger, {ok, HereKey, Value});
+        true ->
+            {ok, HereKey, Value}
+    end.
+
+-spec foldl(fun((Key::key(), Value::value(), Acc::term()) -> term()), term(), bindict()) ->
+                   term().
+foldl(Fun, Acc, <<?MAGIC, _:32, Binary/binary>>) ->
+    foldl_node(Fun, Acc, Binary).
+
+foldl_node(_Fun, Acc, <<>>) ->
+    Acc;
+
+foldl_node(Fun, Acc, <<KeySize:16, Key:KeySize/binary,
+                       BinSizeSmaller:32, Smaller:BinSizeSmaller/binary,
+                       ValueSize:32, Value:ValueSize/binary,
+                       Bigger/binary>>) ->
+    Acc1 = foldl_node(Fun, Acc, Smaller),
+    Acc2 = Fun(Key, Value, Acc1),
+    foldl_node(Fun, Acc2, Bigger).
+
+
+-spec fold_until_stop(function(), term(), bindict()) -> {stopped, term()} | {ok, term()}.
+
+fold_until_stop(Fun, Acc, <<?MAGIC, _:32, Bin/binary>>) ->
+    fold_until_stop2(Fun, {continue, Acc}, Bin).
+
+fold_until_stop2(_Fun,{stop,Result},_) ->
+    {stopped, Result};
+fold_until_stop2(_Fun,{continue, Acc},<<>>) ->
+    {ok, Acc};
+fold_until_stop2(Fun,{continue, Acc}, <<KeySize:16, Key:KeySize/binary,
+                                       BinSizeSmaller:32, Smaller:BinSizeSmaller/binary,
+                                       ValueSize:32, Value:ValueSize/binary,
+                                       Bigger/binary>>) ->
+
+    case fold_until_stop2(Fun, {continue, Acc}, Smaller) of
+        {stopped, Result} ->
+            {stopped, Result};
+        {ok, Acc1} ->
+            ContinueOrStopAcc = Fun({Key,Value}, Acc1),
+            fold_until_stop2(Fun, ContinueOrStopAcc, Bigger)
+    end.
+
+
+-spec foldr(fun((Key::key(), Value::value(), Acc::term()) -> term()), term(), bindict()) ->
+                   term().
+foldr(Fun, Acc, <<?MAGIC, _:32, Binary/binary>>) ->
+    foldr_node(Fun, Acc, Binary).
+
+foldr_node(_Fun, Acc, <<>>) ->
+    Acc;
+
+foldr_node(Fun, Acc, <<KeySize:16, Key:KeySize/binary,
+                       BinSizeSmaller:32, Smaller:BinSizeSmaller/binary,
+                       ValueSize:32, Value:ValueSize/binary,
+                       Bigger/binary>>) ->
+    Acc1 = foldr_node(Fun, Acc, Bigger),
+    Acc2 = Fun(Key, Value, Acc1),
+    foldr_node(Fun, Acc2, Smaller).
+
+
+from_orddict(OrdDict) ->
+    from_gb_tree(gb_trees:from_orddict(OrdDict)).
+
+-ifdef(TEST).
+
+speed_test_() ->
+    {timeout, 600,
+     fun() ->
+             Start = 100000000000000,
+             N = 100000,
+             Keys = lists:seq(Start, Start+N),
+             KeyValuePairs = lists:map(fun (I) -> {<<I:64/integer>>, <<255:8/integer>>} end,
+                                       Keys),
+
+             %% Will mostly be unique, if N is bigger than 10000
+             ReadKeys = [<<(lists:nth(random:uniform(N), Keys)):64/integer>> || _ <- lists:seq(1, 1000)],
+             B = from_orddict(KeyValuePairs),
+             time_reads(B, N, ReadKeys)
+     end}.
+
+
+geq_test() ->
+    B = from_orddict([{<<2>>,<<2>>},{<<4>>,<<4>>},{<<6>>,<<6>>},{<<122>>,<<122>>}]),
+    none = find_geq(<<1>>, B),
+    {ok, <<2>>, <<2>>} = find_geq(<<2>>, B),
+    {ok, <<2>>, <<2>>} = find_geq(<<3>>, B),
+    {ok, <<4>>, <<4>>} = find_geq(<<5>>, B),
+    {ok, <<6>>, <<6>>} = find_geq(<<100>>, B),
+    {ok, <<122>>, <<122>>} = find_geq(<<150>>, B),
+    true.
+
+
+time_reads(B, Size, ReadKeys) ->
+    Parent = self(),
+    spawn(
+      fun() ->
+              Runs = 20,
+              Timings =
+                  lists:map(
+                    fun (_) ->
+                            StartTime = now(),
+                            find_many(B, ReadKeys),
+                            timer:now_diff(now(), StartTime)
+                    end, lists:seq(1, Runs)),
+
+              Rps = 1000000 / ((lists:sum(Timings) / length(Timings)) / 1000),
+              error_logger:info_msg("Average over ~p runs, ~p keys in dict~n"
+                                    "Average fetch ~p keys: ~p us, max: ~p us~n"
+                                    "Average fetch 1 key: ~p us~n"
+                                    "Theoretical sequential RPS: ~w~n",
+                                    [Runs, Size, length(ReadKeys),
+                                     lists:sum(Timings) / length(Timings),
+                                     lists:max(Timings),
+                                     (lists:sum(Timings) / length(Timings)) / length(ReadKeys),
+                                     trunc(Rps)]),
+
+              Parent ! done
+      end),
+    receive done -> ok after 1000 -> ok end.
+
+-spec find_many(bindict(), [key()]) -> non_neg_integer().
+find_many(B, Keys) ->
+    lists:foldl(fun (K, N) ->
+                        case find(K, B) of
+                            {ok, _} -> N+1;
+                            error -> N
+                        end
+                end,
+                0, Keys).
+
+-endif.