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perf(ft-asm): optimize away remote segments identical to local

This commit is contained in:
Andrew Mayorov 2023-02-27 15:45:00 +03:00 committed by Ilya Averyanov
parent ccba65e1ea
commit 0af7e2a002
1 changed files with 22 additions and 3 deletions
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25
apps/emqx_ft/src/emqx_ft_assembly.erl
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@ -137,6 +137,10 @@ append_filemeta(Asm, Node, Fragment = #{fragment := {filemeta, Meta}}) ->
meta = orddict:store(Meta, {Node, Fragment}, Asm#asm.meta)
}.
append_segmentinfo(Asm, _Node, #{fragment := {segment, #{size := 0}}}) ->
% NOTE
% Empty segments are valid but meaningless for coverage.
Asm;
append_segmentinfo(Asm, Node, Fragment = #{fragment := {segment, Info}}) ->
Offset = maps:get(offset, Info),
Size = maps:get(size, Info),
@ -151,16 +155,17 @@ append_segmentinfo(Asm, Node, Fragment = #{fragment := {segment, Info}}) ->
coverage([{{Offset, _, _, _}, _Segment} | Rest], Cursor, Sz) when Offset < Cursor ->
coverage(Rest, Cursor, Sz);
coverage([{{Cursor, _Locality, MEnd, Node}, Segment} | Rest], Cursor, Sz) ->
coverage([{{Cursor, _Locality, MEnd, Node}, Segment} | _Rest] = Segments, Cursor, Sz) ->
% NOTE
% We consider only whole fragments here, so for example from the point of view of
% this algo `[{Offset1 = 0, Size1 = 15}, {Offset2 = 10, Size2 = 10}]` has no
% coverage.
case coverage(Rest, -MEnd, Sz) of
Tail = tail(Segments),
case coverage(Tail, -MEnd, Sz) of
Coverage when is_list(Coverage) ->
[{Node, Segment} | Coverage];
Missing = {missing, _} ->
case coverage(Rest, Cursor, Sz) of
case coverage(Tail, Cursor, Sz) of
CoverageAlt when is_list(CoverageAlt) ->
CoverageAlt;
{missing, _} ->
@ -174,6 +179,20 @@ coverage([], Cursor, Sz) when Cursor < Sz ->
coverage([], Cursor, Cursor) ->
[].
tail([Segment | Rest]) ->
tail(Segment, Rest).
tail({{Cursor, _, MEnd, _}, _} = Segment, [{{Cursor, _, MEnd, _}, _} | Rest]) ->
% NOTE
% Discarding segments with same offset / size, potentially located on other nodes.
% This is an optimization. They won't participate in coverage anyway given we're
% currently optimizing coverage towards locality. Yet if we instead decide to
% optimize for node dominance (e.g. compute such coverage that most of the data
% located on a single node) we'll need to account them again.
tail(Segment, Rest);
tail(_Segment, Tail) ->
Tail.
dominant(Coverage) ->
% TODO: needs improvement, better defined _dominance_, maybe some score
Freqs = frequencies(fun({Node, Segment}) -> {Node, segsize(Segment)} end, Coverage),