diff --git a/dbms/src/Core/BlockInfo.cpp b/dbms/src/Core/BlockInfo.cpp
index 3c8d1ccef7c..aae9723d0ed 100644
--- a/dbms/src/Core/BlockInfo.cpp
+++ b/dbms/src/Core/BlockInfo.cpp
@@ -60,7 +60,7 @@ void BlockInfo::read(ReadBuffer & in)
 
 void BlockMissingValues::setBit(size_t column_idx, size_t row_idx)
 {
-    RowsBitMask & mask = columns_defaults[column_idx];
+    RowsBitMask & mask = rows_mask_by_column_id[column_idx];
     mask.resize(row_idx + 1);
     mask[row_idx] = true;
 }
@@ -68,8 +68,8 @@ void BlockMissingValues::setBit(size_t column_idx, size_t row_idx)
 const BlockMissingValues::RowsBitMask & BlockMissingValues::getDefaultsBitmask(size_t column_idx) const
 {
     static RowsBitMask none;
-    auto it = columns_defaults.find(column_idx);
-    if (it != columns_defaults.end())
+    auto it = rows_mask_by_column_id.find(column_idx);
+    if (it != rows_mask_by_column_id.end())
         return it->second;
     return none;
 }
diff --git a/dbms/src/Core/BlockInfo.h b/dbms/src/Core/BlockInfo.h
index 9e23de688af..32a09d8cf70 100644
--- a/dbms/src/Core/BlockInfo.h
+++ b/dbms/src/Core/BlockInfo.h
@@ -53,16 +53,16 @@ public:
 
     const RowsBitMask & getDefaultsBitmask(size_t column_idx) const;
     void setBit(size_t column_idx, size_t row_idx);
-    bool empty() const { return columns_defaults.empty(); }
-    size_t size() const { return columns_defaults.size(); }
-    void clear() { columns_defaults.clear(); }
+    bool empty() const { return rows_mask_by_column_id.empty(); }
+    size_t size() const { return rows_mask_by_column_id.size(); }
+    void clear() { rows_mask_by_column_id.clear(); }
 
 private:
     using RowsMaskByColumnId = std::unordered_map<size_t, RowsBitMask>;
 
-    /// If columns_defaults[column_id][row_id] is true related value in Block should be replaced with column default.
+    /// If rows_mask_by_column_id[column_id][row_id] is true related value in Block should be replaced with column default.
     /// It could contain less columns and rows then related block.
-    RowsMaskByColumnId columns_defaults;
+    RowsMaskByColumnId rows_mask_by_column_id;
 };
 
 }