Use log at random

Easy way to sample frequent things - especially when they'r ein ocverag
equeries

src/leveled_bookie.erl

@@ -847,7 +847,7 @@ snapshot_store(State, SnapType, Query) ->
                                     source_penciller=State#state.penciller},
     {ok, LedgerSnapshot} = leveled_penciller:pcl_start(PCLopts),
     LedgerCache = readycache_forsnapshot(State#state.ledger_cache, Query),
-    leveled_log:log_timer("B0004", [cache_size(LedgerCache)], SW),
+    leveled_log:log_randomtimer("B0004", [cache_size(LedgerCache)], SW, 0.1),
     case SnapType of
         store ->
             InkerOpts = #inker_options{start_snapshot=true,

src/leveled_log.erl

@@ -9,6 +9,7 @@
 
 -export([log/2,
             log_timer/3,
+            log_randomtimer/4,
             put_timing/4,
             head_timing/4,
             get_timing/3,
@@ -349,6 +350,14 @@ log_timer(LogReference, Subs, StartTime) ->
             ok
     end.
 
+log_randomtimer(LogReference, Subs, StartTime, RandomProb) ->
+    case random:uniform() < RandomProb of
+        true ->
+            log_timer(LogReference, Subs, StartTime);
+        false ->
+            ok
+    end.
+
 %% Make a log of put timings split out by actor - one log for every
 %% PUT_LOGPOINT puts
 

src/leveled_penciller.erl

@@ -408,9 +408,7 @@ handle_call({fetch_keys, StartKey, EndKey, AccFun, InitAcc, MaxKeys},
             List ->
                 List
         end,
-    leveled_log:log_timer("P0037",
-                            [length(L0AsList)],
-                            SW),
+    leveled_log:log_randomtimer("P0037", [length(L0AsList)], SW, 0.1),
     SetupFoldFun =
         fun(Level, Acc) ->
             Pointers = leveled_pmanifest:range_lookup(State#state.manifest,