diff --git a/db/db_test.cc b/db/db_test.cc
index a8973a102..5941dc2d2 100644
--- a/db/db_test.cc
+++ b/db/db_test.cc
@@ -7751,6 +7751,12 @@ class ModelDB: public DB {
   class ModelSnapshot : public Snapshot {
    public:
     KVMap map_;
+
+    virtual SequenceNumber GetSequenceNumber() const {
+      // no need to call this
+      assert(false);
+      return 0;
+    }
   };
 
   explicit ModelDB(const Options& options) : options_(options) {}
diff --git a/db/snapshot.h b/db/snapshot.h
index 45c66eabc..de9897f24 100644
--- a/db/snapshot.h
+++ b/db/snapshot.h
@@ -20,6 +20,8 @@ class SnapshotImpl : public Snapshot {
  public:
   SequenceNumber number_;  // const after creation
 
+  virtual SequenceNumber GetSequenceNumber() const { return number_; }
+
  private:
   friend class SnapshotList;
 
diff --git a/include/rocksdb/db.h b/include/rocksdb/db.h
index a519db7f6..a4141f38b 100644
--- a/include/rocksdb/db.h
+++ b/include/rocksdb/db.h
@@ -64,6 +64,10 @@ static const int kMinorVersion = __ROCKSDB_MINOR__;
 // A Snapshot is an immutable object and can therefore be safely
 // accessed from multiple threads without any external synchronization.
 class Snapshot {
+ public:
+  // returns Snapshot's sequence number
+  virtual SequenceNumber GetSequenceNumber() const = 0;
+
  protected:
   virtual ~Snapshot();
 };