[FOLD] Address feedback

src/ripple/nodestore/impl/Database.cpp

@@ -50,7 +50,15 @@ void
 Database::waitReads()
 {
  std::unique_lock<std::mutex> l(readLock_);
- // Wake in two generations
+ // Wake in two generations.
+ // Each generation is a full pass over the space.
+ // If we're in generation N and you issue a request,
+ // that request will only be done during generation N
+ // if it happens to land after where the pass currently is.
+ // But, if not, it will definitely be done during generation
+ // N+1 since the request was in the table before that pass
+ // even started. So when you reach generation N+2,
+ // you know the request is done.
  std::uint64_t const wakeGen = readGen_ + 2;
  while (! readShut_ && ! read_.empty() && (readGen_ < wakeGen))
  readGenCondVar_.wait(l);

src/ripple/nodestore/impl/DatabaseShardImp.cpp

@@ -737,7 +737,7 @@ DatabaseShardImp::selectCache(std::uint32_t seq)
  cache = std::make_pair(incomplete_->pCache(),
  incomplete_->nCache());
  }
- return std::move(cache);
+ return cache;
 }
 
 

src/ripple/shamap/SHAMap.h

@@ -87,8 +87,7 @@ class SHAMap
  mutable SHAMapState state_;
  SHAMapType type_;
  bool backed_ = true; // Map is backed by the database
- bool full_ = false; // Indicates all nodes should reside in a local store.
-
+ bool full_ = false; // Map is believed complete in database
 
 public:
  class version