diff --git a/src/common/ptr_util.h b/src/common/ptr_util.h
index 481ccc7f393..feeba9d0bc7 100644
--- a/src/common/ptr_util.h
+++ b/src/common/ptr_util.h
@@ -29,6 +29,14 @@ struct ObserverOrUniquePtr : private D {
   explicit ObserverOrUniquePtr(T* ptr, ObserverOrUnique own) : ptr_(ptr), own_(own) {}
 
   ObserverOrUniquePtr(ObserverOrUniquePtr&& p) : ptr_(p.ptr_), own_(p.own_) { p.Release(); }
+  ObserverOrUniquePtr& operator=(ObserverOrUniquePtr&& p) {
+    Reset(p.ptr_);
+    own_ = p.own_;
+    p.Release();
+
+    return *this;
+  }
+
   ObserverOrUniquePtr(const ObserverOrUniquePtr&) = delete;
   ObserverOrUniquePtr& operator=(const ObserverOrUniquePtr&) = delete;
 
@@ -45,7 +53,15 @@ struct ObserverOrUniquePtr : private D {
     return ptr_;
   }
 
+  void Reset(T* ptr = nullptr) {
+    if (own_ == ObserverOrUnique::Unique) {
+      (*this)(ptr_);
+    }
+
+    ptr_ = ptr;
+  }
+
  private:
   T* ptr_;
   ObserverOrUnique own_;
-};
\ No newline at end of file
+};
diff --git a/src/storage/redis_db.cc b/src/storage/redis_db.cc
index 4fbf006be5b..be3901a19ea 100644
--- a/src/storage/redis_db.cc
+++ b/src/storage/redis_db.cc
@@ -92,16 +92,15 @@ rocksdb::Status Database::Expire(const Slice &user_key, int timestamp) {
   }
   if (metadata.expire == timestamp) return rocksdb::Status::OK();
 
-  char *buf = new char[value.size()];
-  memcpy(buf, value.data(), value.size());
+  auto buf = std::make_unique<char[]>(value.size());
+  memcpy(buf.get(), value.data(), value.size());
   // +1 to skip the flags
-  EncodeFixed32(buf + 1, (uint32_t)timestamp);
+  EncodeFixed32(buf.get() + 1, (uint32_t)timestamp);
   auto batch = storage_->GetWriteBatchBase();
   WriteBatchLogData log_data(kRedisNone, {std::to_string(kRedisCmdExpire)});
   batch->PutLogData(log_data.Encode());
-  batch->Put(metadata_cf_handle_, ns_key, Slice(buf, value.size()));
+  batch->Put(metadata_cf_handle_, ns_key, Slice(buf.get(), value.size()));
   s = storage_->Write(storage_->DefaultWriteOptions(), batch->GetWriteBatch());
-  delete[] buf;
   return s;
 }
 
diff --git a/tests/cppunit/ptr_util_test.cc b/tests/cppunit/ptr_util_test.cc
index b685fe41523..22e306475a7 100644
--- a/tests/cppunit/ptr_util_test.cc
+++ b/tests/cppunit/ptr_util_test.cc
@@ -21,12 +21,13 @@
 #include "common/ptr_util.h"
 
 #include <gtest/gtest.h>
-struct Counter {
-  Counter(int* i) : i_(i) { ++*i_; }
+struct Counter {  // NOLINT
+  explicit Counter(int* i) : i_(i) { ++*i_; }
   ~Counter() { --*i_; }
 
   int* i_;
 };
+
 TEST(ObserverOrUniquePtr, Unique) {
   int v = 0;
   {
@@ -38,8 +39,14 @@ TEST(ObserverOrUniquePtr, Unique) {
 
 TEST(CompositePtr, Observer) {
   int v = 0;
-  ObserverOrUniquePtr<Counter> observer(new Counter{&v}, ObserverOrUnique::Observer);
+  Counter* c = nullptr;
+  {
+    ObserverOrUniquePtr<Counter> observer(new Counter{&v}, ObserverOrUnique::Observer);
+    ASSERT_EQ(v, 1);
+
+    c = observer.Get();
+  }
   ASSERT_EQ(v, 1);
-  delete observer.Release();
+  delete c;
   ASSERT_EQ(v, 0);
-}
\ No newline at end of file
+}