diff --git a/bpt/include/bpt/bpt.hpp b/bpt/include/bpt/bpt.hpp
index 642b203..6eb67b0 100644
--- a/bpt/include/bpt/bpt.hpp
+++ b/bpt/include/bpt/bpt.hpp
@@ -87,8 +87,10 @@ class BPlusTreeIndexer {
   }
 
  private:
-  page_id_t root_page_id;  // stored in the first 4 (0-3) bytes of RawDatMemory
-  uint64_t siz;            // stored in the next 8 (4-11) bytes of RawDatMemory
+  page_id_t root_page_id;  // stored in the first 4 (0-3) bytes of RawDatMemory, this directly operates on the buf
+                           // maintained by DiskManager, BufferPoolManager only passes the pointer to it
+  uint64_t siz;            // stored in the next 8 (4-11) bytes of RawDatMemory, this directly operates on the buf
+                           // maintained by DiskManager, BufferPoolManager only passes the pointer to it
   static KeyComparator key_cmp;
   std::shared_mutex latch;
   BufferPoolManager *bpm;
diff --git a/bpt/include/bpt/bpt_page.hpp b/bpt/include/bpt/bpt_page.hpp
index 9c2e906..e5fb462 100644
--- a/bpt/include/bpt/bpt_page.hpp
+++ b/bpt/include/bpt/bpt_page.hpp
@@ -5,7 +5,7 @@
 #pragma pack(push, 1)
 template <typename KeyType, size_t kPageSize = 4096>
 class BPlusTreePage {
-  typedef std::pair<KeyType, b_plus_tree_value_index_t> value_type;
+  typedef std::pair<KeyType, default_numeric_index_t> value_type;
   page_id_t p_n;
   page_id_t p_parent;
   uint8_t is_leaf;
diff --git a/bpt/include/bpt/config.h b/bpt/include/bpt/config.h
index 3eec52d..20c1a76 100644
--- a/bpt/include/bpt/config.h
+++ b/bpt/include/bpt/config.h
@@ -5,7 +5,6 @@
 extern const size_t kPageSize;
 typedef uint32_t default_numeric_index_t;
 typedef default_numeric_index_t page_id_t;
-typedef default_numeric_index_t block_id_t;
 typedef default_numeric_index_t frame_id_t;
 typedef default_numeric_index_t b_plus_tree_value_index_t;
 extern const b_plus_tree_value_index_t kInvalidValueIndex;