[TTreeProcessorMT] Remove protections to cope with task interleaving

tree/treeplayer/inc/ROOT/TTreeProcessorMT.hxx

@@ -71,7 +71,6 @@ namespace ROOT {
          // NOTE: fFriends must come before fChain to be deleted after it, see ROOT-9281 for more details
          std::vector<std::unique_ptr<TChain>> fFriends; ///< Friends of the tree/chain
          std::unique_ptr<TChain> fChain;                ///< Chain on which to operate
-         std::vector<Long64_t> fLoadedEntries;          ///<! Per-task loaded entries (for task interleaving)
 
          ////////////////////////////////////////////////////////////////////////////////
          /// Construct fChain, also adding friends if needed and injecting knowledge of offsets if available.
@@ -161,20 +160,6 @@ namespace ROOT {
             // we need to return the entry list too, as it needs to be in scope as long as the reader is
             return std::make_pair(std::move(reader), std::move(localList));
          }
-
-         //////////////////////////////////////////////////////////////////////////
-         /// Push a new loaded entry to the stack.
-         void PushTaskFirstEntry(Long64_t entry) { fLoadedEntries.push_back(entry); }
-
-         //////////////////////////////////////////////////////////////////////////
-         /// Restore the tree of the previous loaded entry, if any.
-         void PopTaskFirstEntry()
-         {
-            fLoadedEntries.pop_back();
-            if (fLoadedEntries.size() > 0) {
-               fChain->LoadTree(fLoadedEntries.back());
-            }
-         }
       };
    } // End of namespace Internal
 

tree/treeplayer/src/TTreeProcessorMT.cxx

@@ -335,17 +335,11 @@ void TTreeProcessorMT::Process(std::function<void(TTreeReader &)> func)
          shouldUseGlobalEntries ? entries : std::vector<Long64_t>({theseClustersAndEntries.second[0]});
 
       auto processCluster = [&](const Internal::EntryCluster &c) {
-         // This task will operate with the tree that contains start
-         treeView->PushTaskFirstEntry(c.start);
-
          std::unique_ptr<TTreeReader> reader;
          std::unique_ptr<TEntryList> elist;
          std::tie(reader, elist) = treeView->GetTreeReader(c.start, c.end, fTreeName, theseFiles, fFriendInfo,
                                                            fEntryList, theseEntries, friendEntries);
          func(*reader);
-
-         // In case of task interleaving, we need to load here the tree of the parent task
-         treeView->PopTaskFirstEntry();
       };
 
       pool.Foreach(processCluster, thisFileClusters);