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Curtail trimmed slot crazyness

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There was complicated and confusing code that achieved nothing for
effiency when trimming slots.  the expensive part (binary_to_term) was
still needed on every block, and it was hard to get code coverage and
make sense of what it was really trying to achieve.

This is now much simpler - and may set us up for potential further
indexing help.
This commit is contained in:
martinsumner 2017-03-19 21:47:22 +00:00
parent c203e2ee06
commit f20aba9c8b
1 changed files with 22 additions and 67 deletions
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89
src/leveled_sst.erl
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@ -909,41 +909,34 @@ binaryslot_trimmedlist(FullBin, StartKey, EndKey) ->
LTrimFun = fun({K, _V}) -> K < StartKey end,
RTrimFun = fun({K, _V}) -> not leveled_codec:endkey_passed(EndKey, K) end,
BlockFetchFun =
fun(Length, {Acc, Bin}) ->
case Length of
0 ->
{Acc, Bin};
_ ->
fun(Length, {Acc, Bin, Continue}) ->
case {Length, Continue} of
{0, _} ->
{Acc, Bin, false};
{_, true} ->
<<Block:Length/binary, Rest/binary>> = Bin,
BlockList = binary_to_term(Block),
{FirstKey, _FV} = lists:nth(1, BlockList),
{LastKey, _LV} = lists:last(BlockList),
TrimBools = trim_booleans(FirstKey, LastKey,
StartKey, EndKey),
case TrimBools of
{true, _, _, _} ->
{Acc, Rest};
{false, true, _, _} ->
{Acc ++ BlockList, Rest};
{false, false, true, false} ->
case StartKey > LastKey of
true ->
{Acc, Rest, true};
false ->
{_LDrop, RKeep} = lists:splitwith(LTrimFun,
BlockList),
{Acc ++ RKeep, Rest};
{false, false, false, true} ->
{LKeep, _RDrop} = lists:splitwith(RTrimFun,
BlockList),
{Acc ++ LKeep, Rest};
{false, false, true, true} ->
{_LDrop, RKeep} = lists:splitwith(LTrimFun,
BlockList),
{LKeep, _RDrop} = lists:splitwith(RTrimFun, RKeep),
{Acc ++ LKeep, Rest}
end
case leveled_codec:endkey_passed(EndKey, LastKey) of
true ->
{LKeep, _RDrop} = lists:splitwith(RTrimFun, RKeep),
{Acc ++ LKeep, Rest, false};
false ->
{Acc ++ RKeep, Rest, true}
end
end;
{_ , false} ->
{Acc, Bin, false}
end
end,
{Out, _Rem} =
{Out, _Rem, _Continue} =
case crc_check_slot(FullBin) of
{BlockLengths, RestBin} ->
<<B1P:32/integer,
@ -952,51 +945,13 @@ binaryslot_trimmedlist(FullBin, StartKey, EndKey) ->
B3L:32/integer,
B4L:32/integer>> = BlockLengths,
<<_PosBinIndex:B1P/binary, Blocks/binary>> = RestBin,
lists:foldl(BlockFetchFun, {[], Blocks}, [B1L, B2L, B3L, B4L]);
lists:foldl(BlockFetchFun, {[], Blocks, true}, [B1L, B2L, B3L, B4L]);
crc_wonky ->
{[], <<>>}
{[], <<>>, true}
end,
Out.
trim_booleans(FirstKey, _LastKey, StartKey, all) ->
FirstKeyPassedStart = FirstKey > StartKey,
case FirstKeyPassedStart of
true ->
{false, true, false, false};
false ->
{false, false, true, false}
end;
trim_booleans(_FirstKey, LastKey, all, EndKey) ->
LastKeyPassedEnd = leveled_codec:endkey_passed(EndKey, LastKey),
case LastKeyPassedEnd of
true ->
{false, false, false, true};
false ->
{false, true, false, false}
end;
trim_booleans(FirstKey, LastKey, StartKey, EndKey) ->
FirstKeyPassedStart = FirstKey > StartKey,
PreRange = LastKey < StartKey,
PostRange = leveled_codec:endkey_passed(EndKey, FirstKey),
OutOfRange = PreRange or PostRange,
LastKeyPassedEnd = leveled_codec:endkey_passed(EndKey, LastKey),
case OutOfRange of
true ->
{true, false, false, false};
false ->
case {FirstKeyPassedStart, LastKeyPassedEnd} of
{true, false} ->
{false, true, false, false};
{false, false} ->
{false, false, true, false};
{true, true} ->
{false, false, false, true};
{false, true} ->
{false, false, true, true}
end
end.
crc_check_slot(FullBin) ->
<<CRC32:32/integer, SlotBin/binary>> = FullBin,