Address review comments

More efficient traversal of list to score.

src/leveled_pclerk.erl

@@ -188,7 +188,7 @@ merge(SrcLevel, Manifest, RootPath, OptsSST) ->
     end,
     SelectMethod =
         case leveled_rand:uniform(100) of
-            R when R < ?GROOMING_PERC ->
+            R when R =< ?GROOMING_PERC ->
                 {grooming, fun grooming_scorer/1};
             _ ->
                 random
@@ -297,18 +297,23 @@ do_merge(KL1, KL2, SinkLevel, SinkB, RP, NewSQN, MaxSQN, OptsSST, Additions) ->
     end.
 
 -spec grooming_scorer(list(manifest_entry())) -> manifest_entry().
-grooming_scorer(Sample) ->
+grooming_scorer([ME  | MEs]) ->
-    ScoringFun = 
+    InitTombCount = leveled_sst:sst_gettombcount(ME#manifest_entry.owner),
-        fun(ME) ->
+    {HighestTC, BestME} = grooming_scorer(InitTombCount, ME, MEs),
-            TombCount = leveled_sst:sst_gettombcount(ME#manifest_entry.owner),
-            {TombCount, ME}
-        end,
-    ScoredSample =
-        lists:reverse(lists:ukeysort(1, lists:map(ScoringFun, Sample))),
-    [{HighestTC, BestME}|_Rest] = ScoredSample,
     leveled_log:log("PC024", [HighestTC]),
     BestME.
 
+grooming_scorer(HighestTC, BestME, []) ->
+     {HighestTC, BestME};
+grooming_scorer(HighestTC, BestME, [ME | MEs]) ->
+    TombCount = leveled_sst:sst_gettombcount(ME#manifest_entry.owner),
+    case TombCount > HighestTC of
+        true ->
+            grooming_scorer(TombCount, ME, MEs);
+        false ->
+            grooming_scorer(HighestTC, BestME, MEs)
+   end.
+
 return_deletions(ManifestSQN, PendingDeletionD) ->
     % The returning of deletions had been seperated out as a failure to fetch
     % here had caased crashes of the clerk.  The root cause of the failure to

src/leveled_pmanifest.erl

@@ -464,7 +464,8 @@ mergefile_selector(Manifest, LevelIdx, {grooming, ScoringFun}) ->
     Sample =
         lists:usort(lists:foldl(SelectorFun, [], lists:seq(1, ?GROOM_SAMPLE))),
     % Note that Entries may be less than GROOM_SAMPLE, if same one picked
-    % multiple times
+    % multiple times.  Level cannot be empty, as otherwise a merge would not
+    % have been chosen at this level
     ScoringFun(Sample).