diff --git a/be/src/exec/parquet/parquet-column-readers.cc b/be/src/exec/parquet/parquet-column-readers.cc
index 512632be2..58cc12f21 100644
--- a/be/src/exec/parquet/parquet-column-readers.cc
+++ b/be/src/exec/parquet/parquet-column-readers.cc
@@ -1323,7 +1323,7 @@ int BaseScalarColumnReader::FillPositionsInCandidateRange(int rows_remaining,
     int rep_level = rep_levels_.CacheGetNext();
     if (rep_level == 0) ++row_count;
     ++val_count;
-    if (pos_slot_desc_ != nullptr) {
+    if (pos_writer.IsValid()) {
       if (rep_level <= max_rep_level() - 1) pos_current_value_ = 0;
       *pos_writer.Advance() = pos_current_value_++;
     }
diff --git a/be/src/util/mem-util.h b/be/src/util/mem-util.h
index a7125a984..16e808574 100644
--- a/be/src/util/mem-util.h
+++ b/be/src/util/mem-util.h
@@ -31,17 +31,21 @@ namespace impala {
 template <typename T>
 struct StrideWriter {
   // The next element to write to. May not be aligned to the natural alignment of T.
+  // Can be null for convenience, but the StrideWriter cannot be used in that case.
   T* current;
 
   // The stride in bytes between subsequent values.
   int64_t stride;
 
   explicit StrideWriter(T* current, int64_t stride) : current(current), stride(stride) {
-    DCHECK(current != nullptr);
   }
 
+  /// No other functions can be called if false.
+  ALWAYS_INLINE bool IsValid() const { return current != nullptr; }
+
   /// Set the next element to 'val' and advance 'current' to the next element.
   ALWAYS_INLINE void SetNext(T& val) {
+    DCHECK(IsValid());
     // memcpy() is necessary because 'current' may not be aligned.
     memcpy(current, &val, sizeof(T));
     SkipNext(1);
@@ -49,6 +53,7 @@ struct StrideWriter {
 
   /// Return a pointer to the current element and advance 'current' to the next element.
   ALWAYS_INLINE T* Advance() {
+    DCHECK(IsValid());
     T* curr = current;
     SkipNext(1);
     return curr;
@@ -56,11 +61,13 @@ struct StrideWriter {
 
   /// Set the next 'count' elements to 'val', advancing 'current' by 'count' values.
   void SetNext(T& val, int64_t count) {
+    DCHECK(IsValid());
     for (int64_t i = 0; i < count; ++i) SetNext(val);
   }
 
   /// Advance 'current' by 'count' values.
   ALWAYS_INLINE void SkipNext(int64_t count) {
+    DCHECK(IsValid());
     DCHECK_GE(count, 0);
     current = reinterpret_cast<T*>(reinterpret_cast<uint8_t*>(current) + stride * count);
   }
diff --git a/testdata/workloads/functional-query/queries/QueryTest/nested-types-parquet-page-index.test b/testdata/workloads/functional-query/queries/QueryTest/nested-types-parquet-page-index.test
index 8c85b575d..8a372f782 100644
--- a/testdata/workloads/functional-query/queries/QueryTest/nested-types-parquet-page-index.test
+++ b/testdata/workloads/functional-query/queries/QueryTest/nested-types-parquet-page-index.test
@@ -702,3 +702,12 @@ BIGINT, DECIMAL
 ---- RUNTIME_PROFILE
 aggregation(SUM, NumStatsFilteredPages): 6
 ====
+---- QUERY
+# Regression test for IMPALA-9572.
+select count(l_partkey) from tpch_nested_parquet.customer.c_orders.o_lineitems
+where l_partkey < 10
+---- RESULTS
+263
+---- TYPES
+BIGINT
+====