diff --git a/db/arena_wrapped_db_iter.h b/db/arena_wrapped_db_iter.h
index cdf9046a9..3442440c1 100644
--- a/db/arena_wrapped_db_iter.h
+++ b/db/arena_wrapped_db_iter.h
@@ -34,7 +34,7 @@ class Version;
 // the same as the inner DBIter.
 class ArenaWrappedDBIter : public Iterator {
  public:
-  virtual ~ArenaWrappedDBIter() {
+  ~ArenaWrappedDBIter() override {
     if (db_iter_ != nullptr) {
       db_iter_->~DBIter();
     } else {
diff --git a/db/kv_checksum.h b/db/kv_checksum.h
index 196c6f7c9..bfec80b51 100644
--- a/db/kv_checksum.h
+++ b/db/kv_checksum.h
@@ -117,7 +117,7 @@ class ProtectionInfoKVO {
   friend class ProtectionInfoKVOS<T>;
   friend class ProtectionInfoKVOC<T>;
 
-  ProtectionInfoKVO<T>(T val) : info_(val) {
+  explicit ProtectionInfoKVO<T>(T val) : info_(val) {
     static_assert(sizeof(ProtectionInfoKVO<T>) == sizeof(T), "");
   }
 
@@ -155,7 +155,7 @@ class ProtectionInfoKVOC {
  private:
   friend class ProtectionInfoKVO<T>;
 
-  ProtectionInfoKVOC<T>(T val) : kvo_(val) {
+  explicit ProtectionInfoKVOC<T>(T val) : kvo_(val) {
     static_assert(sizeof(ProtectionInfoKVOC<T>) == sizeof(T), "");
   }
 
@@ -193,7 +193,7 @@ class ProtectionInfoKVOS {
  private:
   friend class ProtectionInfoKVO<T>;
 
-  ProtectionInfoKVOS<T>(T val) : kvo_(val) {
+  explicit ProtectionInfoKVOS<T>(T val) : kvo_(val) {
     static_assert(sizeof(ProtectionInfoKVOS<T>) == sizeof(T), "");
   }
 
diff --git a/db/listener_test.cc b/db/listener_test.cc
index ce53d297b..e3839fe77 100644
--- a/db/listener_test.cc
+++ b/db/listener_test.cc
@@ -1427,12 +1427,6 @@ TEST_F(EventListenerTest, BlobDBCompactFiles) {
 
 class BlobDBFileLevelEventListener : public EventListener {
  public:
-  BlobDBFileLevelEventListener() {
-    files_started_.store(0);
-    files_created_.store(0);
-    files_deleted_.store(0);
-  }
-
   void OnBlobFileCreationStarted(
       const BlobFileCreationBriefInfo& info) override {
     files_started_++;
@@ -1471,9 +1465,9 @@ class BlobDBFileLevelEventListener : public EventListener {
   }
 
  private:
-  std::atomic<uint32_t> files_started_;
-  std::atomic<uint32_t> files_created_;
-  std::atomic<uint32_t> files_deleted_;
+  std::atomic<uint32_t> files_started_{};
+  std::atomic<uint32_t> files_created_{};
+  std::atomic<uint32_t> files_deleted_{};
 };
 
 TEST_F(EventListenerTest, BlobDBFileTest) {