Fetch specific block only

Rely on CRC check in zlib.  Still need to catch on failure

src/leveled_sst.erl

@@ -404,20 +404,22 @@ fetch(LedgerKey, Hash, State) ->
                                         State#state.blockindex_cache),
             case CachedBlockIdx of 
                 none ->
+                    io:format("Looking for key without cache~n"),
                     SlotBin = read_slot(State#state.handle, Slot),
-                    {Result, BlockIdx} = binaryslot_get(SlotBin, 
+                    {Result,
-                                                        LedgerKey, 
+                        BlockLengths,
-                                                        Hash, 
+                        BlockIdx} = binaryslot_get(SlotBin, LedgerKey, Hash),
-                                                        none),
                     BlockIndexCache = array:set(SlotID - 1, 
-                                                BlockIdx,
+                                                <<BlockLengths/binary,
+                                                    BlockIdx/binary>>,
                                                 State#state.blockindex_cache),
                     {Result, 
                         slot_fetch, 
                         Slot#slot_index_value.slot_id,
                         State#state{blockindex_cache = BlockIndexCache}};
-                _ ->
+                <<BlockLengths:20/binary, BlockIdx/binary>> ->
-                    PosList = find_pos(CachedBlockIdx, 
+                    io:format("Looking for key with cache~n"),
+                    PosList = find_pos(BlockIdx, 
                                         double_hash(Hash, LedgerKey), 
                                         [], 
                                         0),
@@ -425,12 +427,12 @@ fetch(LedgerKey, Hash, State) ->
                         [] ->
                             {not_present, slot_bloom,  SlotID, State};
                         _ ->
-                            SlotBin = read_slot(State#state.handle, Slot),
+                            Result = check_blocks(PosList,
-                            Result = binaryslot_get(SlotBin, 
+                                                    State#state.handle,
-                                                    LedgerKey, 
+                                                    Slot,
-                                                    Hash, 
+                                                    BlockLengths,
-                                                    {true, PosList}),
+                                                    LedgerKey),
-                            {element(1, Result), slot_fetch, SlotID, State}
+                            {Result, slot_fetch, SlotID, State}
                     end 
             end
     end.
@@ -607,45 +609,6 @@ build_all_slots(KVL, SC, Pos, SlotID, SlotIdx, BlockIdxA, SlotsBin) ->
                     array:set(SlotID - 1, BlockIndex, BlockIdxA),
                     <<SlotsBin/binary, SlotBin/binary>>).
 
-read_slot(Handle, Slot) ->
-    {ok, SlotBin} = file:pread(Handle,
-                                Slot#slot_index_value.start_position,
-                                Slot#slot_index_value.length),
-    SlotBin.
-
-read_slots(Handle, SlotList) ->
-    PointerMapFun =
-        fun(Pointer) ->
-            {Slot, SK, EK} = 
-                case Pointer of 
-                    {pointer, _Pid, Slot0, SK0, EK0} ->
-                        {Slot0, SK0, EK0};
-                    {pointer, Slot0, SK0, EK0} ->
-                        {Slot0, SK0, EK0}
-                end,
-
-            {Slot#slot_index_value.start_position, 
-                Slot#slot_index_value.length,
-                SK, 
-                EK}
-        end,
-    
-    LengthList = lists:map(PointerMapFun, SlotList),
-    StartPos = element(1, lists:nth(1, LengthList)),
-    EndPos = element(1, lists:last(LengthList)) 
-                + element(2, lists:last(LengthList)),
-    {ok, MultiSlotBin} = file:pread(Handle, StartPos, EndPos - StartPos),
-
-    BinSplitMapFun = 
-        fun({SP, L, SK, EK}) -> 
-                    Start = SP - StartPos,
-                    <<_Pre:Start/binary, 
-                        SlotBin:L/binary, 
-                        _Post/binary>> = MultiSlotBin,
-                    {SlotBin, SK, EK}
-        end,
-    
-    lists:map(BinSplitMapFun, LengthList).
 
 generate_filenames(RootFilename) ->
     Ext = filename:extension(RootFilename),
@@ -819,27 +782,96 @@ generate_binary_slot(KVL) ->
     CRC32 = erlang:crc32(SlotBin),
     FullBin = <<CRC32:32/integer, SlotBin/binary>>,
 
-    {PosBinIndex1, FullBin, HashL}.
+    {<<Lengths/binary, PosBinIndex1/binary>>, FullBin, HashL}.
 
 
-binaryslot_get(FullBin, Key, Hash, CachedPosLookup) ->
+check_blocks([], _Handle, _Slot, _BlockLengths, _LedgerKey) ->
+    not_present;
+check_blocks([Pos|Rest], Handle, Slot, BlockLengths, LedgerKey) ->
+    {BlockNumber, BlockPos} = revert_position(Pos),
+    io:format("Checking BlockNumber ~w in BlockPos ~w~n",
+                [BlockNumber, BlockPos]),
+    BlockBin = read_block(Handle, Slot, BlockLengths, BlockNumber),
+    BlockL = binary_to_term(BlockBin),
+    {K, V} = lists:nth(BlockPos, BlockL),
+    case K of 
+        LedgerKey ->
+            io:format("Key mismatch in check_blocks~n"),
+            {K, V};
+        _ ->
+            check_blocks(Rest, Handle, Slot, BlockLengths, LedgerKey)
+    end.
+
+
+read_block(Handle, Slot, BlockLengths, BlockID) ->
+    {BlockPos, Offset, Length} = block_offsetandlength(BlockLengths, BlockID),
+    io:format("Reading offset ~w Length ~w~n", [Offset, Length]),
+    {ok, BlockBin} = file:pread(Handle,
+                                Slot#slot_index_value.start_position
+                                    + BlockPos
+                                    + Offset
+                                    + 24,
+                                    % 4-byte CRC, 4 byte pos, 4x4 byte lengths
+                                Length),
+    BlockBin.
+
+read_slot(Handle, Slot) ->
+    {ok, SlotBin} = file:pread(Handle,
+                                Slot#slot_index_value.start_position,
+                                Slot#slot_index_value.length),
+    SlotBin.
+
+read_slots(Handle, SlotList) ->
+    PointerMapFun =
+        fun(Pointer) ->
+            {Slot, SK, EK} = 
+                case Pointer of 
+                    {pointer, _Pid, Slot0, SK0, EK0} ->
+                        {Slot0, SK0, EK0};
+                    {pointer, Slot0, SK0, EK0} ->
+                        {Slot0, SK0, EK0}
+                end,
+
+            {Slot#slot_index_value.start_position, 
+                Slot#slot_index_value.length,
+                SK, 
+                EK}
+        end,
+    
+    LengthList = lists:map(PointerMapFun, SlotList),
+    StartPos = element(1, lists:nth(1, LengthList)),
+    EndPos = element(1, lists:last(LengthList)) 
+                + element(2, lists:last(LengthList)),
+    {ok, MultiSlotBin} = file:pread(Handle, StartPos, EndPos - StartPos),
+
+    BinSplitMapFun = 
+        fun({SP, L, SK, EK}) -> 
+                    Start = SP - StartPos,
+                    <<_Pre:Start/binary, 
+                        SlotBin:L/binary, 
+                        _Post/binary>> = MultiSlotBin,
+                    {SlotBin, SK, EK}
+        end,
+    
+    lists:map(BinSplitMapFun, LengthList).
+
+
+binaryslot_get(FullBin, Key, Hash) ->
     case crc_check_slot(FullBin) of 
-        {Lengths, Rest} ->
+        {BlockLengths, Rest} ->
-            B1P = element(1, Lengths),
+            <<B1P:32/integer, _R/binary>> = BlockLengths, 
-            case CachedPosLookup of 
-                {true, PosList} ->
-                    <<_PosBinIndex:B1P/binary, Blocks/binary>> = Rest,
-                    {fetch_value(PosList, Lengths, Blocks, Key), none};
-                none ->
             <<PosBinIndex:B1P/binary, Blocks/binary>> = Rest,
             PosList = find_pos(PosBinIndex,
                                 double_hash(Hash, Key), 
                                 [], 
                                 0),
-                    {fetch_value(PosList, Lengths, Blocks, Key), PosBinIndex}
+            {fetch_value(PosList, BlockLengths, Blocks, Key),
-            end;
+                BlockLengths,
+                PosBinIndex};
         crc_wonky ->
-            {not_present, none}
+            {not_present,
+                none,
+                none}
     end.
 
 binaryslot_tolist(FullBin) ->
@@ -856,8 +888,12 @@ binaryslot_tolist(FullBin) ->
 
     {Out, _Rem} = 
         case crc_check_slot(FullBin) of 
-            {Lengths, RestBin} ->
+            {BlockLengths, RestBin} ->
-                {B1P, B1L, B2L, B3L, B4L} = Lengths,
+                <<B1P:32/integer,
+                    B1L:32/integer,
+                    B2L:32/integer,
+                    B3L:32/integer,
+                    B4L:32/integer>> = BlockLengths,
                 <<_PosBinIndex:B1P/binary, Blocks/binary>> = RestBin,
                 lists:foldl(BlockFetchFun, {[], Blocks}, [B1L, B2L, B3L, B4L]);
             crc_wonky ->
@@ -908,8 +944,12 @@ binaryslot_trimmedlist(FullBin, StartKey, EndKey) ->
 
     {Out, _Rem} = 
         case crc_check_slot(FullBin) of 
-            {Lengths, RestBin} ->
+            {BlockLengths, RestBin} ->
-                {B1P, B1L, B2L, B3L, B4L} = Lengths,
+                <<B1P:32/integer,
+                    B1L:32/integer,
+                    B2L:32/integer,
+                    B3L:32/integer,
+                    B4L:32/integer>> = BlockLengths,
                 <<_PosBinIndex:B1P/binary, Blocks/binary>> = RestBin,
                 lists:foldl(BlockFetchFun, {[], Blocks}, [B1L, B2L, B3L, B4L]);
             crc_wonky ->
@@ -957,65 +997,68 @@ trim_booleans(FirstKey, LastKey, StartKey, EndKey) ->
     end.
 
 
-
-
 crc_check_slot(FullBin) ->
     <<CRC32:32/integer, SlotBin/binary>> = FullBin,
     case erlang:crc32(SlotBin) of 
         CRC32 ->
-            <<B1P:32/integer, 
+            <<BlockLengths:20/binary, Rest/binary>> = SlotBin,
-                B1L:32/integer, 
+            {BlockLengths, Rest};
-                B2L:32/integer, 
-                B3L:32/integer, 
-                B4L:32/integer,
-                Rest/binary>> = SlotBin,
-            Lengths = {B1P, B1L, B2L, B3L, B4L},
-            {Lengths, Rest};
         _ ->
             leveled_log:log("SST09", []),
             crc_wonky
     end.
 
+block_offsetandlength(BlockLengths, BlockID) ->
+    <<BlocksPos:32/integer, BlockLengths0:16/binary>> = BlockLengths,
+    case BlockID of
+        1 ->
+            <<B1L:32/integer, _BR/binary>> = BlockLengths0,
+            {BlocksPos, 0, B1L};
+        2 ->
+            <<B1L:32/integer, B2L:32/integer, _BR/binary>> = BlockLengths0,
+            {BlocksPos, B1L, B2L};
+        3 ->
+            <<B1L:32/integer,
+                B2L:32/integer,
+                B3L:32/integer,
+                _BR/binary>> = BlockLengths0,
+            {BlocksPos, B1L + B2L, B3L};
+        4 ->
+            <<B1L:32/integer,
+                B2L:32/integer,
+                B3L:32/integer,
+                B4L:32/integer>> = BlockLengths0,
+            {BlocksPos, B1L + B2L + B3L, B4L}
+    end.
+
 double_hash(Hash, Key) ->
     H2 = erlang:phash2(Key),
     (Hash bxor H2) band 32767.
 
-fetch_value([], _Lengths, _Blocks, _Key) ->
+fetch_value([], _BlockLengths, _Blocks, _Key) ->
     not_present;
-fetch_value([Pos|Rest], Lengths, Blocks, Key) ->
+fetch_value([Pos|Rest], BlockLengths, Blocks, Key) ->
-    BlockNumber = (Pos div 32) + 1,
+    {BlockNumber, BlockPos} = revert_position(Pos),
-    BlockPos = (Pos rem 32) + 1,
+    {_BlockPos,
-    BlockL = 
+        Offset,
-        case BlockNumber of 
+        Length} = block_offsetandlength(BlockLengths, BlockNumber),
-            1 ->
+    <<_Pre:Offset/binary, Block:Length/binary, _Rest/binary>> = Blocks,
-                B1L = element(2, Lengths),
+    BlockL = binary_to_term(Block),
-                <<Block:B1L/binary, _Rest/binary>> = Blocks,
-                binary_to_term(Block);
-            2 ->
-                B1L = element(2, Lengths),
-                B2L = element(3, Lengths),
-                <<_Pass:B1L/binary, Block:B2L/binary, _Rest/binary>> = Blocks,
-                binary_to_term(Block);
-            3 ->
-                PreL = element(2, Lengths) + element(3, Lengths),
-                B3L = element(4, Lengths),
-                <<_Pass:PreL/binary, Block:B3L/binary, _Rest/binary>> = Blocks,
-                binary_to_term(Block);
-            4 ->
-                {_B1P, B1L, B2L, B3L, B4L} = Lengths,
-                PreL = B1L + B2L + B3L,
-                <<_Pass:PreL/binary, Block:B4L/binary>> = Blocks,
-                binary_to_term(Block)
-        end,
-
     {K, V} = lists:nth(BlockPos, BlockL),
     case K of 
         Key ->
+            io:format("Key mismatch in fetch_value~n"),
             {K, V};
         _ ->
-            fetch_value(Rest, Lengths, Blocks, Key)
+            fetch_value(Rest, BlockLengths, Blocks, Key)
     end.
 
+
+revert_position(Pos) ->
+    BlockNumber = (Pos div 32) + 1,
+    BlockPos = (Pos rem 32) + 1,
+    {BlockNumber, BlockPos}.
+
 find_pos(<<>>, _Hash, PosList, _Count) ->
     PosList;
 find_pos(<<1:1/integer, Hash:15/integer, T/binary>>, Hash, PosList, Count) ->
@@ -1272,7 +1315,7 @@ indexed_list_mixedkeys2_test() ->
 indexed_list_allindexkeys_test() ->
     Keys = lists:sublist(lists:ukeysort(1, generate_indexkeys(150)), 128),
     {PosBinIndex1, FullBin, _HL} = generate_binary_slot(Keys),
-    ?assertMatch(<<127:8/integer>>, PosBinIndex1),
+    ?assertMatch(<<_BL:20/binary, 127:8/integer>>, PosBinIndex1),
     % SW = os:timestamp(),
     BinToList = binaryslot_tolist(FullBin),
     % io:format(user,
@@ -1285,7 +1328,7 @@ indexed_list_allindexkeys_test() ->
 indexed_list_allindexkeys_trimmed_test() ->
     Keys = lists:sublist(lists:ukeysort(1, generate_indexkeys(150)), 128),
     {PosBinIndex1, FullBin, _HL} = generate_binary_slot(Keys),
-    ?assertMatch(<<127:8/integer>>, PosBinIndex1),
+    ?assertMatch(<<_BL:20/binary, 127:8/integer>>, PosBinIndex1),
     ?assertMatch(Keys, binaryslot_trimmedlist(FullBin, 
                                                 {i, 
                                                     "Bucket", 
@@ -1351,7 +1394,7 @@ indexed_list_mixedkeys_bitflip_test() ->
 
 test_binary_slot(FullBin, Key, Hash, ExpectedValue) ->
     % SW = os:timestamp(),
-    {ReturnedValue, _} = binaryslot_get(FullBin, Key, Hash, none),
+    {ReturnedValue, _BLs, _Idx} = binaryslot_get(FullBin, Key, Hash),
     ?assertMatch(ExpectedValue, ReturnedValue).
     % io:format(user, "Fetch success in ~w microseconds ~n",
     %             [timer:now_diff(os:timestamp(), SW)]).