diff --git a/db/snapshot_impl.h b/db/snapshot_impl.h
index c9ddabdec8..edaabade7a 100644
--- a/db/snapshot_impl.h
+++ b/db/snapshot_impl.h
@@ -56,6 +56,9 @@ class SnapshotList {
     count_ = 0;
   }
 
+  // No copy-construct.
+  SnapshotList(const SnapshotList&) = delete;
+
   bool empty() const { return list_.next_ == &list_; }
   SnapshotImpl* oldest() const { assert(!empty()); return list_.next_; }
   SnapshotImpl* newest() const { assert(!empty()); return list_.prev_; }
diff --git a/utilities/blob_db/blob_db_impl.cc b/utilities/blob_db/blob_db_impl.cc
index da9a3d13ec..7cbd5809fa 100644
--- a/utilities/blob_db/blob_db_impl.cc
+++ b/utilities/blob_db/blob_db_impl.cc
@@ -1254,11 +1254,11 @@ bool BlobDBImpl::VisibleToActiveSnapshot(
   // [earliest_sequence, obsolete_sequence). But doing so will make the
   // implementation more complicated.
   SequenceNumber obsolete_sequence = bfile->GetObsoleteSequence();
-  SequenceNumber oldest_snapshot = 0;
+  SequenceNumber oldest_snapshot = kMaxSequenceNumber;
   {
     // Need to lock DBImpl mutex before access snapshot list.
     InstrumentedMutexLock l(db_impl_->mutex());
-    auto snapshots = db_impl_->snapshots();
+    auto& snapshots = db_impl_->snapshots();
     if (!snapshots.empty()) {
       oldest_snapshot = snapshots.oldest()->GetSequenceNumber();
     }