diff --git a/db/range_del_aggregator.cc b/db/range_del_aggregator.cc
index 2e22dd86158..18eeff152cd 100644
--- a/db/range_del_aggregator.cc
+++ b/db/range_del_aggregator.cc
@@ -195,6 +195,10 @@ Status RangeDelAggregator::AddTombstones(
   input->SeekToFirst();
   bool first_iter = true;
   while (input->Valid()) {
+    // The tombstone map holds slices into the iterator's memory. This assert
+    // ensures pinning the iterator also pins the keys/values.
+    assert(input->IsKeyPinned() && input->IsValuePinned());
+
     if (first_iter) {
       if (rep_ == nullptr) {
         InitRep({upper_bound_});
diff --git a/table/block_based_table_builder.cc b/table/block_based_table_builder.cc
index 607d2a5340f..85c41fe5105 100644
--- a/table/block_based_table_builder.cc
+++ b/table/block_based_table_builder.cc
@@ -300,7 +300,7 @@ struct BlockBasedTableBuilder::Rep {
                       : 0),
         data_block(table_options.block_restart_interval,
                    table_options.use_delta_encoding),
-        range_del_block(1),  // TODO(andrewkr): restart_interval unnecessary
+        range_del_block(1 /* block_restart_interval */),
         internal_prefix_transform(_ioptions.prefix_extractor),
         compression_type(_compression_type),
         compression_opts(_compression_opts),
diff --git a/util/testutil.h b/util/testutil.h
index 62a4de1ab75..d6b0a7095e3 100644
--- a/util/testutil.h
+++ b/util/testutil.h
@@ -179,6 +179,9 @@ class VectorIterator : public InternalIterator {
 
   virtual Status status() const override { return Status::OK(); }
 
+  virtual bool IsKeyPinned() const override { return true; }
+  virtual bool IsValuePinned() const override { return true; }
+
  private:
   std::vector<std::string> keys_;
   std::vector<std::string> values_;