diff --git a/dbms/src/Columns/ColumnArray.h b/dbms/src/Columns/ColumnArray.h
index 5b10e02272e..43bb55c73d6 100644
--- a/dbms/src/Columns/ColumnArray.h
+++ b/dbms/src/Columns/ColumnArray.h
@@ -87,7 +87,7 @@ class ColumnArray final : public COWPtrHelper<IColumn, ColumnArray>
     void insertFrom(const IColumn & src_, size_t n) override;
     void insertDefault() override;
     void popBack(size_t n) override;
-    /// TODO: If result_size_hint < 0, makes reserve() using size of column after being filtered, not source column.
+    /// TODO: If result_size_hint < 0, makes reserve() using size of filtered column, not source column to avoid some OOM issues.
     ColumnPtr filter(const Filter & filt, ssize_t result_size_hint) const override;
     ColumnPtr permute(const Permutation & perm, size_t limit) const override;
     int compareAt(size_t n, size_t m, const IColumn & rhs_, int nan_direction_hint) const override;
diff --git a/dbms/src/Columns/IColumn.h b/dbms/src/Columns/IColumn.h
index ecc0a3f986e..410f4641e60 100644
--- a/dbms/src/Columns/IColumn.h
+++ b/dbms/src/Columns/IColumn.h
@@ -216,7 +216,7 @@ class IColumn : public COWPtr<IColumn>
       * Is used in WHERE and HAVING operations.
       * If result_size_hint > 0, then makes advance reserve(result_size_hint) for the result column;
       *  if 0, then don't makes reserve(),
-      *  otherwise (i.e. < 0), makes reserve() using size of column after being filtered.
+      *  otherwise (i.e. < 0), makes reserve() using size of filtered column.
       */
     using Filter = PaddedPODArray<UInt8>;
     virtual Ptr filter(const Filter & filt, ssize_t result_size_hint) const = 0;