Merge pull request #307 from martinsumner/mas-i306-lessrandomreads

Mas i306 lessrandomreads

src/leveled_cdb.erl

@@ -130,6 +130,7 @@
 -define(DELETE_TIMEOUT, 10000).
 -define(TIMING_SAMPLECOUNTDOWN, 5000).
 -define(TIMING_SAMPLESIZE, 100).
+-define(GETPOS_FACTOR, 8).
 -define(MAX_OBJECT_SIZE, 1000000000). 
     % 1GB but really should be much smaller than this
 
@@ -270,24 +271,28 @@ cdb_getpositions(Pid, SampleSize) ->
         all ->
             FoldFun = 
                 fun(Index, Acc) ->
-                    cdb_getpositions_fromidx(Pid, all, Index, Acc)
+                    PosList = cdb_getpositions_fromidx(Pid, all, Index, []),
+                    lists:merge(Acc, lists:sort(PosList))
                 end,
             IdxList = lists:seq(0, 255),
             lists:foldl(FoldFun, [], IdxList);
         S0 ->
+            FC = ?GETPOS_FACTOR * S0,
             FoldFun = 
                 fun({_R, Index}, Acc) ->
                     case length(Acc) of
-                        S0 ->
+                        FC ->
                             Acc;
-                        L when L < S0 ->
+                        L when L < FC ->
-                            cdb_getpositions_fromidx(Pid, S0, Index, Acc)
+                            cdb_getpositions_fromidx(Pid, FC, Index, Acc)
                     end
                 end,
             RandFun = fun(X) -> {leveled_rand:uniform(), X} end,
             SeededL = lists:map(RandFun, lists:seq(0, 255)),
             SortedL = lists:keysort(1, SeededL),
-            lists:foldl(FoldFun, [], SortedL)
+            PosList0 = lists:foldl(FoldFun, [], SortedL),
+            P1 = leveled_rand:uniform(max(1, length(PosList0) - S0)),
+            lists:sublist(lists:sort(PosList0), P1, S0)
     end.
 
 cdb_getpositions_fromidx(Pid, SampleSize, Index, Acc) ->
@@ -1226,10 +1231,9 @@ scan_index_returnpositions(Handle, Position, Count, PosList0) ->
                     [HPosition|PosList]
             end
         end,
-    PosList = lists:foldl(AddPosFun,
+    lists:foldl(AddPosFun,
                 PosList0,
-                            read_next_n_integerpairs(Handle, Count)),
+                read_next_n_integerpairs(Handle, Count)).
-    lists:reverse(PosList).
 
 
 %% Take an active file and write the hash details necessary to close that

src/leveled_iclerk.erl

@@ -507,13 +507,22 @@ schedule_compaction(CompactionHours, RunsPerDay, CurrentTS) ->
 %% calls.
 check_single_file(CDB, FilterFun, FilterServer, MaxSQN, SampleSize, BatchSize) ->
     FN = leveled_cdb:cdb_filename(CDB),
+    SW = os:timestamp(),
     PositionList = leveled_cdb:cdb_getpositions(CDB, SampleSize),
     KeySizeList = fetch_inbatches(PositionList, BatchSize, CDB, []),
     Score = 
         size_comparison_score(KeySizeList, FilterFun, FilterServer, MaxSQN),
-    leveled_log:log("IC004", [FN, Score]),
+    safely_log_filescore(PositionList, FN, Score, SW),
     Score.
 
+safely_log_filescore([], FN, Score, SW) ->
+    leveled_log:log_timer("IC004", [Score, empty, FN], SW);
+safely_log_filescore(PositionList, FN, Score, SW) ->
+    AvgJump =
+        (lists:last(PositionList) - lists:nth(1, PositionList))
+            div length(PositionList),
+    leveled_log:log_timer("IC004", [Score, AvgJump, FN], SW).
+
 size_comparison_score(KeySizeList, FilterFun, FilterServer, MaxSQN) ->
     FoldFunForSizeCompare =
         fun(KS, {ActSize, RplSize}) ->
@@ -548,7 +557,7 @@ size_comparison_score(KeySizeList, FilterFun, FilterServer, MaxSQN) ->
     {ActiveSize, ReplacedSize} = R0,
     case ActiveSize + ReplacedSize of
         0 ->
-            100.0;
+            0.0;
         _ ->
             100 * ActiveSize / (ActiveSize + ReplacedSize)
     end.
@@ -1113,7 +1122,6 @@ compact_empty_file_test() ->
     FN1 = leveled_inker:filepath(RP, 1, new_journal),
     CDBopts = #cdb_options{binary_mode=true},
     {ok, CDB1} = leveled_cdb:cdb_open_writer(FN1, CDBopts),
-    ok = leveled_cdb:cdb_put(CDB1, {1, stnd, test_ledgerkey("Key1")}, <<>>),
     {ok, FN2} = leveled_cdb:cdb_complete(CDB1),
     {ok, CDB2} = leveled_cdb:cdb_open_reader(FN2),
     LedgerSrv1 = [{8, {o, "Bucket", "Key1", null}},
@@ -1121,7 +1129,7 @@ compact_empty_file_test() ->
                     {3, {o, "Bucket", "Key3", null}}],
     LedgerFun1 = fun(_Srv, _Key, _ObjSQN) -> false end,
     Score1 = check_single_file(CDB2, LedgerFun1, LedgerSrv1, 9, 8, 4),
-    ?assertMatch(100.0, Score1),
+    ?assertMatch(0.0, Score1),
     ok = leveled_cdb:cdb_deletepending(CDB2),
     ok = leveled_cdb:cdb_destroy(CDB2).
 

src/leveled_log.erl

@@ -336,7 +336,7 @@
         {info, "Scoring of compaction runs complete with highest score=~w " 
                 ++ "with run of run_length=~w"}},
     {"IC004",
-        {info, "Score for filename ~s is ~w"}},
+        {info, "Score=~w with mean_byte_jump=~w for filename ~s"}},
     {"IC005",
         {info, "Compaction to be performed on ~w files with score of ~w"}},
     {"IC006",