Add log of higher than expected ratio of cache sizes

Warn at startup if this ratio is high.  Not sure how snapshots will perform if there are a lot of ledger cache sin the list.  However, it should still work.  basic_SUITE/load_count test intended to demonstrate that a large ratio is still functional

src/leveled_bookie.erl

@@ -1125,6 +1125,20 @@ init([Opts]) ->
                 ConfiguredCacheSize div (100 div ?CACHE_SIZE_JITTER),
             CacheSize = 
                 ConfiguredCacheSize + erlang:phash2(self()) rem CacheJitter,
+            PCLMaxSize =
+                PencillerOpts#penciller_options.max_inmemory_tablesize,
+            CacheRatio = PCLMaxSize div ConfiguredCacheSize,
+                % It is expected that the maximum size of the penciller
+                % in-memory store should not be more than about 10 x the size
+                % of the ledger cache.  In this case there will be a larger
+                % than tested list of ledger_caches in the penciller memory,
+                % and performance may be unpredictable
+            case CacheRatio > 32 of
+                true ->
+                    leveled_log:log("B0020", [PCLMaxSize, ConfiguredCacheSize]);
+                false ->
+                    ok
+            end,
             
             {HeadOnly, HeadLookup} = 
                 case proplists:get_value(head_only, Opts) of 

src/leveled_log.erl

@@ -75,6 +75,9 @@
     {"B0019",
         {warn, "Use of book_indexfold with constraint of Bucket ~w with "
                     ++ "no StartKey is deprecated"}},
+    {"B0020",
+        {warn, "Ratio of penciller cache size ~w to bookie's memory "
+                    ++ "cache size ~w is larger than expected"}},
 
     {"R0001",
         {debug, "Object fold to process batch of ~w objects"}},