Merge branch 'master' into columnfamilies

Conflicts:
	db/db_impl.cc
	db/db_impl_readonly.cc
	db/db_test.cc
	db/version_edit.cc
	db/version_edit.h
	db/version_set.cc
	db/version_set.h
	db/version_set_reduce_num_levels.cc

include/rocksdb/db.h

@@ -291,6 +291,7 @@ class DB {
   }
 
   // Compact the underlying storage for the key range [*begin,*end].
+  // The actual compaction interval might be superset of [*begin, *end].
   // In particular, deleted and overwritten versions are discarded,
   // and the data is rearranged to reduce the cost of operations
   // needed to access the data.  This operation should typically only

include/rocksdb/memtablerep.h

@@ -111,27 +111,23 @@ class MemTableRep {
   };
 
   // Return an iterator over the keys in this representation.
-  virtual std::shared_ptr<Iterator> GetIterator() = 0;
+  virtual Iterator* GetIterator() = 0;
 
   // Return an iterator over at least the keys with the specified user key. The
   // iterator may also allow access to other keys, but doesn't have to. Default:
   // GetIterator().
-  virtual std::shared_ptr<Iterator> GetIterator(const Slice& user_key) {
-    return GetIterator();
-  }
+  virtual Iterator* GetIterator(const Slice& user_key) { return GetIterator(); }
 
   // Return an iterator over at least the keys with the specified prefix. The
   // iterator may also allow access to other keys, but doesn't have to. Default:
   // GetIterator().
-  virtual std::shared_ptr<Iterator> GetPrefixIterator(const Slice& prefix) {
+  virtual Iterator* GetPrefixIterator(const Slice& prefix) {
     return GetIterator();
   }
 
   // Return an iterator that has a special Seek semantics. The result of
   // a Seek might only include keys with the same prefix as the target key.
-  virtual std::shared_ptr<Iterator> GetDynamicPrefixIterator() {
-    return GetIterator();
-  }
+  virtual Iterator* GetDynamicPrefixIterator() { return GetIterator(); }
 
  protected:
   // When *key is an internal key concatenated with the value, returns the
@@ -144,8 +140,8 @@ class MemTableRep {
 class MemTableRepFactory {
  public:
   virtual ~MemTableRepFactory() { };
-  virtual std::shared_ptr<MemTableRep> CreateMemTableRep(
-    MemTableRep::KeyComparator&, Arena*) = 0;
+  virtual MemTableRep* CreateMemTableRep(MemTableRep::KeyComparator&,
+                                         Arena*) = 0;
   virtual const char* Name() const = 0;
 };
 
@@ -161,8 +157,8 @@ class VectorRepFactory : public MemTableRepFactory {
   const size_t count_;
 public:
   explicit VectorRepFactory(size_t count = 0) : count_(count) { }
-  virtual std::shared_ptr<MemTableRep> CreateMemTableRep(
-    MemTableRep::KeyComparator&, Arena*) override;
+  virtual MemTableRep* CreateMemTableRep(MemTableRep::KeyComparator&,
+                                         Arena*) override;
   virtual const char* Name() const override {
     return "VectorRepFactory";
   }
@@ -171,8 +167,8 @@ public:
 // This uses a skip list to store keys. It is the default.
 class SkipListFactory : public MemTableRepFactory {
 public:
-  virtual std::shared_ptr<MemTableRep> CreateMemTableRep(
-    MemTableRep::KeyComparator&, Arena*) override;
+ virtual MemTableRep* CreateMemTableRep(MemTableRep::KeyComparator&,
+                                        Arena*) override;
   virtual const char* Name() const override {
     return "SkipListFactory";
   }

include/rocksdb/statistics.h

@@ -242,53 +242,10 @@ struct HistogramData {
   double standard_deviation;
 };
 
-
-class Histogram {
- public:
-  // clear's the histogram
-  virtual void Clear() = 0;
-  virtual ~Histogram();
-  // Add a value to be recorded in the histogram.
-  virtual void Add(uint64_t value) = 0;
-
-  virtual std::string ToString() const = 0;
-
-  // Get statistics
-  virtual double Median() const = 0;
-  virtual double Percentile(double p) const = 0;
-  virtual double Average() const = 0;
-  virtual double StandardDeviation() const = 0;
-  virtual void Data(HistogramData * const data) const = 0;
-
-};
-
-/**
- * A dumb ticker which keeps incrementing through its life time.
- * Thread safe. Locking managed by implementation of this interface.
- */
-class Ticker {
- public:
-  Ticker() : count_(0) { }
-
-  inline void setTickerCount(uint64_t count) {
-    count_ = count;
-  }
-
-  inline void recordTick(int count = 1) {
-    count_ += count;
-  }
-
-  inline uint64_t getCount() {
-    return count_;
-  }
-
- private:
-  std::atomic_uint_fast64_t count_;
-};
-
 // Analyze the performance of a db
 class Statistics {
  public:
+  virtual ~Statistics() {}
 
   virtual long getTickerCount(Tickers tickerType) = 0;
   virtual void recordTick(Tickers tickerType, uint64_t count = 0) = 0;

include/rocksdb/write_batch.h

@@ -36,7 +36,7 @@ struct SliceParts;
 
 class WriteBatch {
  public:
-  WriteBatch();
+  explicit WriteBatch(size_t reserved_bytes = 0);
   ~WriteBatch();
 
   // Store the mapping "key->value" in the database.
@@ -122,7 +122,10 @@ class WriteBatch {
   Status Iterate(Handler* handler) const;
 
   // Retrieve the serialized version of this batch.
-  std::string Data() { return rep_; }
+  const std::string& Data() const { return rep_; }
+
+  // Retrieve data size of the batch.
+  size_t GetDataSize() const { return rep_.size(); }
 
   // Returns the number of updates in the batch
   int Count() const;