FIXUP: Don't manually track cache size

Not quite sure why I started doing this in the first place. I think it
was becuase I was worried ets:info/2 might be expensive but I can get
away with only calling it once here so no big deal any more.

3 files changed, 45 insertions, 13 deletions

diff --git a/src/ddoc_cache/src/ddoc_cache_lru.erl b/src/ddoc_cache/src/ddoc_cache_lru.erl
index 35173f4b5..27649592d 100644
--- a/src/ddoc_cache/src/ddoc_cache_lru.erl
+++ b/src/ddoc_cache/src/ddoc_cache_lru.erl
@@ -42,7 +42,6 @@
 -record(st, {
     pids, % pid -> key
     dbs, % dbname -> docid -> key -> pid
-    size,
     evictor
 }).
 
@@ -93,7 +92,6 @@ init(_) ->
     {ok, #st{
         pids = Pids,
         dbs = Dbs,
-        size = 0,
         evictor = Evictor
     }}.
 
@@ -109,20 +107,20 @@ terminate(_Reason, St) ->
 handle_call({start, Key, Default}, _From, St) ->
     #st{
         pids = Pids,
-        dbs = Dbs,
-        size = CurSize
+        dbs = Dbs
     } = St,
     case ets:lookup(?CACHE, Key) of
         [] ->
             MaxSize = config:get_integer("ddoc_cache", "max_size", 1000),
+            CurSize = ets:info(?CACHE, size),
             case trim(St, CurSize, max(0, MaxSize)) of
-                {ok, N} ->
+                ok ->
                     true = ets:insert_new(?CACHE, #entry{key = Key}),
                     {ok, Pid} = ddoc_cache_entry:start_link(Key, Default),
                     true = ets:update_element(?CACHE, Key, {#entry.pid, Pid}),
                     ok = khash:put(Pids, Pid, Key),
                     store_key(Dbs, Key, Pid),
-                    {reply, {ok, Pid}, St#st{size = CurSize - N + 1}};
+                    {reply, {ok, Pid}, St};
                 full ->
                     ?EVENT(full, Key),
                     {reply, full, St}
@@ -251,7 +249,7 @@ trim(_, _, 0) ->
     full;
 
 trim(_St, CurSize, MaxSize) when CurSize < MaxSize ->
-    {ok, 0};
+    ok;
 
 trim(St, CurSize, MaxSize) when CurSize >= MaxSize ->
     case ets:first(?LRU) of
@@ -259,7 +257,7 @@ trim(St, CurSize, MaxSize) when CurSize >= MaxSize ->
             full;
         {_Ts, Key, Pid} ->
             remove_entry(St, Key, Pid),
-            {ok, 1}
+            trim(St, CurSize - 1, MaxSize)
     end.
 
 
diff --git a/src/ddoc_cache/test/ddoc_cache_coverage_test.erl b/src/ddoc_cache/test/ddoc_cache_coverage_test.erl
index 395f56048..91182caac 100644
--- a/src/ddoc_cache/test/ddoc_cache_coverage_test.erl
+++ b/src/ddoc_cache/test/ddoc_cache_coverage_test.erl
@@ -33,7 +33,7 @@ coverage_test_() ->
 
 restart_lru() ->
     send_bad_messages(ddoc_cache_lru),
-    ?assertEqual(ok, ddoc_cache_lru:terminate(bang, {st, a, b, c, d})),
+    ?assertEqual(ok, ddoc_cache_lru:terminate(bang, {st, a, b, c})),
     ?assertEqual({ok, foo}, ddoc_cache_lru:code_change(1, foo, [])).
 
 
@@ -47,7 +47,7 @@ restart_evictor() ->
     meck:new(ddoc_cache_ev, [passthrough]),
     try
         State = sys:get_state(ddoc_cache_lru),
-        Evictor = element(5, State),
+        Evictor = element(4, State),
         Ref = erlang:monitor(process, Evictor),
         exit(Evictor, shutdown),
         receive
@@ -57,7 +57,7 @@ restart_evictor() ->
         end,
         meck:wait(ddoc_cache_ev, event, [evictor_died, '_'], 1000),
         NewState = sys:get_state(ddoc_cache_lru),
-        NewEvictor = element(5, NewState),
+        NewEvictor = element(4, NewState),
         ?assertNotEqual(Evictor, NewEvictor)
     after
         meck:unload()
diff --git a/src/ddoc_cache/test/ddoc_cache_lru_test.erl b/src/ddoc_cache/test/ddoc_cache_lru_test.erl
index 77b39cd59..dd7782872 100644
--- a/src/ddoc_cache/test/ddoc_cache_lru_test.erl
+++ b/src/ddoc_cache/test/ddoc_cache_lru_test.erl
@@ -63,7 +63,8 @@ check_lru_test_() ->
             fun check_multi_start/1,
             fun check_multi_open/1,
             fun check_capped_size/1,
-            fun check_full_cache/1
+            fun check_full_cache/1,
+            fun check_cache_refill/1
         ]}
     }.
 
@@ -88,7 +89,7 @@ check_multi_start(_) ->
     ?assert(is_process_alive(Opener)),
     Opener ! go,
     receive {'DOWN', OpenerRef, _, _, _} -> ok end,
-    lists:foreach(fun({CPid, Ref}) ->
+    lists:foreach(fun({_, Ref}) ->
         receive
             {'DOWN', Ref, _, _, normal} -> ok
         end
@@ -159,3 +160,36 @@ check_full_cache(_) ->
         meck:wait(I - 5, ddoc_cache_ev, event, [full, '_'], 1000),
         ?assertEqual(5, ets:info(?CACHE, size))
     end, lists:seq(6, 20)).
+
+
+check_cache_refill({DbName, _}) ->
+    ddoc_cache_tutil:clear(),
+    meck:reset(ddoc_cache_ev),
+
+    InitDDoc = fun(I) ->
+        NumBin = list_to_binary(integer_to_list(I)),
+        DDocId = <<"_design/", NumBin/binary>>,
+        Doc = #doc{id = DDocId, body = {[]}},
+        {ok, _} = fabric:update_doc(DbName, Doc, [?ADMIN_CTX]),
+        {ok, _} = ddoc_cache:open_doc(DbName, DDocId),
+        {ddoc_cache_entry_ddocid, {DbName, DDocId}}
+    end,
+
+    lists:foreach(fun(I) ->
+        Key = InitDDoc(I),
+        couch_log:error("STARTED? ~p", [Key]),
+        meck:wait(ddoc_cache_ev, event, [started, Key], 1000),
+        ?assert(ets:info(?CACHE, size) > 0)
+    end, lists:seq(1, 5)),
+
+    ShardName = element(2, hd(mem3:shards(DbName))),
+    {ok, _} = ddoc_cache_lru:handle_db_event(ShardName, deleted, foo),
+    meck:wait(ddoc_cache_ev, event, [evicted, DbName], 1000),
+    meck:wait(10, ddoc_cache_ev, event, [removed, '_'], 1000),
+    ?assertEqual(0, ets:info(?CACHE, size)),
+
+    lists:foreach(fun(I) ->
+        Key = InitDDoc(I),
+        meck:wait(ddoc_cache_ev, event, [started, Key], 1000),
+        ?assert(ets:info(?CACHE, size) > 0)
+    end, lists:seq(6, 10)).