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Check before update on bloom

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This commit is contained in:
martinsumner 2017-01-02 20:02:49 +00:00
parent 31d4346806
commit 5b4c903d53
2 changed files with 18 additions and 5 deletions
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2
src/leveled_sst.erl
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@ -72,7 +72,7 @@
-define(SLOT_SIZE, 128). % This is not configurable -define(SLOT_SIZE, 128). % This is not configurable
-define(COMPRESSION_LEVEL, 1). -define(COMPRESSION_LEVEL, 1).
-define(BINARY_SETTINGS, [{compressed, ?COMPRESSION_LEVEL}]). -define(BINARY_SETTINGS, [{compressed, ?COMPRESSION_LEVEL}]).
-define(LEVEL_BLOOM_BITS, [{0, 12}, {1, 10}, {2, 8}, {default, 6}]). -define(LEVEL_BLOOM_BITS, [{0, 8}, {1, 10}, {2, 8}, {default, 6}]).
-define(MERGE_SCANWIDTH, 16). -define(MERGE_SCANWIDTH, 16).
-define(DISCARD_EXT, ".discarded"). -define(DISCARD_EXT, ".discarded").
-define(DELETE_TIMEOUT, 10000). -define(DELETE_TIMEOUT, 10000).

21
src/leveled_tinybloom.erl
View file

@ -51,6 +51,7 @@ enter(Key, Bloom) ->
Hash = leveled_codec:magic_hash(Key), Hash = leveled_codec:magic_hash(Key),
enter({hash, Hash}, Bloom). enter({hash, Hash}, Bloom).
check({hash, Hash}, Bloom) -> check({hash, Hash}, Bloom) ->
{Slot0, Q, Bit1, Bit2, Bit3} = split_hash(Hash), {Slot0, Q, Bit1, Bit2, Bit3} = split_hash(Hash),
Slot = Slot0 rem dict:size(Bloom), Slot = Slot0 rem dict:size(Bloom),
@ -83,16 +84,23 @@ check(Key, Bloom) ->
%%%============================================================================ %%%============================================================================
split_hash(Hash) -> split_hash(Hash) ->
Slot = split_for_slot(Hash),
{Q1, H1, H2, H3} = split_for_bits(Hash),
{Slot, Q1, H1, H2, H3}.
split_for_slot(Hash) ->
SlotH1 = Hash band 255, SlotH1 = Hash band 255,
SlotH2 = (Hash bsr 8) band 255, SlotH2 = (Hash bsr 8) band 255,
SlotH3 = (Hash bsr 16) band 255, SlotH3 = (Hash bsr 16) band 255,
SlotH4 = (Hash bsr 24) band 255, SlotH4 = (Hash bsr 24) band 255,
Slot = (SlotH1 bxor SlotH2) bxor (SlotH3 bxor SlotH4), (SlotH1 bxor SlotH2) bxor (SlotH3 bxor SlotH4).
split_for_bits(Hash) ->
Q1 = Hash band 3, Q1 = Hash band 3,
H1 = (Hash bsr 2) band 1023, H1 = (Hash bsr 2) band 1023,
H2 = (Hash bsr 12) band 1023, H2 = (Hash bsr 12) band 1023,
H3 = (Hash bsr 22) band 1023, H3 = (Hash bsr 22) band 1023,
{Slot, Q1, H1, H2, H3}. {Q1, H1, H2, H3}.
split_array(Bin, Q) -> split_array(Bin, Q) ->
case Q of case Q of
@ -113,9 +121,14 @@ split_array(Bin, Q) ->
add_to_array(Bit, BitArray, ArrayLength) -> add_to_array(Bit, BitArray, ArrayLength) ->
RestLen = ArrayLength - Bit - 1, RestLen = ArrayLength - Bit - 1,
<<Head:Bit/bitstring, <<Head:Bit/bitstring,
_B:1/bitstring, B:1/integer,
Rest:RestLen/bitstring>> = BitArray, Rest:RestLen/bitstring>> = BitArray,
<<Head/bitstring, 1:1, Rest/bitstring>>. case B of
0 ->
<<Head/bitstring, 1:1, Rest/bitstring>>;
1 ->
BitArray
end.
getbit(Bit, BitArray, ArrayLength) -> getbit(Bit, BitArray, ArrayLength) ->
RestLen = ArrayLength - Bit - 1, RestLen = ArrayLength - Bit - 1,