Change index.erl to use gen_server and named databases.

Prefetch indices in frontend:fetchmissingentries/2.

1 files changed, 23 insertions, 8 deletions

diff --git a/src/frontend.erl b/src/frontend.erl
index 3b7c15b..b7fa4b1 100644
--- a/src/frontend.erl
+++ b/src/frontend.erl
@@ -302,26 +302,41 @@ check_entry_noreverse(LeafHash, Index) ->
             end
     end.
 
+prefetchindices(Index, []) ->
+    case db:leafhash_for_indices(Index, Index + 1000) of
+        noentry ->
+            case db:leafhash_for_index(Index) of
+                noentry ->
+                    noentry;
+                Hash ->
+                    [Hash]
+            end;
+        Hashes ->
+            Hashes
+    end;
+prefetchindices(_Index, PrefetchList) ->
+    PrefetchList.
+
 -spec fetchmissingentries(non_neg_integer(), non_neg_integer()) -> [binary() | noentry].
 fetchmissingentries(Index, MaxEntries) ->
-    lists:reverse(fetchmissingentries(Index, [], MaxEntries)).
+    lists:reverse(fetchmissingentries(Index, [], [], MaxEntries)).
 
--spec fetchmissingentries(non_neg_integer(), [binary() | noentry], non_neg_integer()) ->
+-spec fetchmissingentries(non_neg_integer(), [binary() | noentry], [binary()], non_neg_integer()) ->
                                  [binary() | noentry].
-fetchmissingentries(_Index, Acc, 0) ->
+fetchmissingentries(_Index, Acc, _PrefetchList, 0) ->
     Acc;
-fetchmissingentries(Index, Acc, MaxEntries) ->
+fetchmissingentries(Index, Acc, PrefetchList, MaxEntries) ->
     lager:debug("index ~p", [Index]),
-    case db:leafhash_for_index(Index) of
+    case prefetchindices(Index, PrefetchList) of
         noentry ->
             Acc;
-        Hash ->
+        [Hash|PrefetchRest] ->
             case db:entry_for_leafhash(Hash) of
                 noentry ->
                     lager:debug("didn't find hash ~p", [Hash]),
-                    fetchmissingentries(Index + 1, [Hash | Acc], MaxEntries - 1);
+                    fetchmissingentries(Index + 1, [Hash | Acc], PrefetchRest, MaxEntries - 1);
                 _ ->
-                    fetchmissingentries(Index + 1, Acc, MaxEntries)
+                    fetchmissingentries(Index + 1, Acc, PrefetchRest, MaxEntries)
             end
     end.