diff --git a/include/podio/DataSource.h b/include/podio/DataSource.h
index d6a2c49e3..17485c124 100644
--- a/include/podio/DataSource.h
+++ b/include/podio/DataSource.h
@@ -35,13 +35,6 @@ class DataSource : public ROOT::RDF::RDataSource {
   ///
   void SetNSlots(unsigned int nSlots) override;
 
-  ///
-  /// @brief Retrieve from podio::DataSource per-thread readers for the desired
-  /// columns.
-  ///
-  template <typename T>
-  std::vector<T**> GetColumnReaders(std::string_view columnName);
-
   ///
   /// @brief Inform podio::DataSource that an event-loop is about to start.
   ///
@@ -111,7 +104,7 @@ class DataSource : public ROOT::RDF::RDataSource {
   std::vector<std::string> m_filePathList = {};
 
   /// Total number of events
-  unsigned int m_nEvents = 0;
+  ULong64_t m_nEvents = 0;
 
   /// Ranges of events available to be processed
   std::vector<std::pair<ULong64_t, ULong64_t>> m_rangesAvailable = {};
@@ -146,18 +139,6 @@ class DataSource : public ROOT::RDF::RDataSource {
   void SetupInput(int nEvents);
 };
 
-///
-/// Not used.
-///
-template <typename T>
-std::vector<T**> DataSource::GetColumnReaders(std::string_view) {
-  // std::cout << "podio::DataSource: Getting column readers for column: " << columnName << std::endl;
-
-  std::vector<T**> readers;
-
-  return readers;
-}
-
 ///
 /// @brief Create RDataFrame from multiple Podio files.
 ///
diff --git a/src/DataSource.cc b/src/DataSource.cc
index 9d861a445..a01504268 100644
--- a/src/DataSource.cc
+++ b/src/DataSource.cc
@@ -36,7 +36,7 @@ void DataSource::SetupInput(int nEvents) {
   unsigned int nEventsInFiles = 0;
   auto podioReader = podio::makeReader(m_filePathList);
   nEventsInFiles = podioReader.getEntries(podio::Category::Event);
-  frame = podio::Frame(podioReader.readFrame(podio::Category::Event, 0));
+  frame = podioReader.readFrame(podio::Category::Event, 0);
 
   // Determine over how many events to run
   if (nEventsInFiles > 0) {
@@ -89,7 +89,7 @@ void DataSource::SetNSlots(unsigned int nSlots) {
   }
 
   for (size_t i = 0; i < m_nSlots; ++i) {
-    m_frames.emplace_back(std::make_unique<podio::Frame>(podio::Frame{}));
+    m_frames.emplace_back(std::make_unique<podio::Frame>());
   }
 }