Revert "Don't use fetch_cache below the page_cache level"

This reverts commit 656900e9ec.

src/leveled_sst.erl

@@ -184,7 +184,6 @@
 -type sst_summary()
         :: #summary{}.
 -type blockindex_cache() :: array:array(). 
--type fetch_cache() :: array:array()|no_cache.
 
 %% yield_blockquery is used to determine if the work necessary to process a
 %% range query beyond the fetching the slot should be managed from within
@@ -208,7 +207,7 @@
                     timings_countdown = 0 :: integer(),
                     starting_pid :: pid()|undefined,
                     fetch_cache = array:new([{size, ?CACHE_SIZE}]) ::
-                        array:array() | redacted | no_cache,
+                        array:array() | redacted,
                     new_slots :: list()|undefined,
                     deferred_startup_tuple :: tuple()|undefined,
                     level :: non_neg_integer()|undefined,
@@ -1103,24 +1102,6 @@ extract_hash(NotHash) ->
 cache_hash({_SegHash, ExtraHash}) when is_integer(ExtraHash) ->
     ExtraHash band (?CACHE_SIZE - 1).
 
--spec fetch_from_cache(
-    non_neg_integer(),
-    fetch_cache()) -> undefined|leveled_codec:ledger_kv().
-fetch_from_cache(_CacheHash, no_cache) ->
-    undefined;
-fetch_from_cache(CacheHash, Cache) ->
-    array:get(CacheHash, Cache).
-
--spec add_to_cache(
-    non_neg_integer(),
-    leveled_codec:ledger_kv()
-    fetch_cache()) -> fetch_cache().
-add_to_cache(_CacheHash, _KV, no_cache) ->
-    no_cache;
-add_to_cache(CacheHash, KV, FetchCache) ->
-    array:set(CacheHash, KV, FetchCache).
-
-
 -spec tune_hash(non_neg_integer()) -> non_neg_integer().
 %% @doc
 %% Only 15 bits of the hash is ever interesting
@@ -1257,7 +1238,7 @@ fetch(LedgerKey, Hash, State, Timings0) ->
                         update_timings(SW2, Timings2, slot_index, true),
                     FetchCache = State#state.fetch_cache,
                     CacheHash = cache_hash(Hash),
-                    case fetch_from_cache(CacheHash, FetchCache) of 
+                    case array:get(CacheHash, FetchCache) of 
                         {LedgerKey, V} ->
                             {_SW4, Timings4} = 
                                 update_timings(SW3, 
@@ -1277,7 +1258,7 @@ fetch(LedgerKey, Hash, State, Timings0) ->
                                                 IdxModDate,
                                                 not_present),
                             FetchCache0 = 
-                                add_to_cache(CacheHash, Result, FetchCache),
+                                array:set(CacheHash, Result, FetchCache),
                             {_SW4, Timings4} = 
                                 update_timings(SW3, 
                                                 Timings3, 
@@ -1401,10 +1382,10 @@ write_file(RootPath, Filename, SummaryBin, SlotsBin,
                                         false),
     FinalName.
 
-read_file(Filename, State, CacheFile) ->
+read_file(Filename, State, LoadPageCache) ->
     {Handle, FileVersion, SummaryBin} = 
         open_reader(filename:join(State#state.root_path, Filename),
-                    CacheFile),
+                    LoadPageCache),
     UpdState0 = imp_fileversion(FileVersion, State),
     {Summary, Bloom, SlotList, TombCount} =
         read_table_summary(SummaryBin, UpdState0#state.tomb_count),
@@ -1415,18 +1396,10 @@ read_file(Filename, State, CacheFile) ->
     leveled_log:log("SST03", [Filename,
                                 Summary#summary.size,
                                 Summary#summary.max_sqn]),
-    FetchCache =
-        case CacheFile of
-            true ->
-                State#state.fetch_cache;
-            false ->
-                no_cache
-        end,
     {UpdState1#state{summary = UpdSummary,
                         handle = Handle,
                         filename = Filename,
-                        tomb_count = TombCount,
-                        fetch_cache = FetchCache},
+                        tomb_count = TombCount},
         Bloom}.
 
 gen_fileversion(PressMethod, IdxModDate, CountOfTombs) ->