From 1b88ac4cb592cc5b097fba2ef62aa5173c685323 Mon Sep 17 00:00:00 2001
From: fangzhuhe <fangzhuhe@bytedance.com>
Date: Tue, 28 Jul 2026 14:51:59 +0800
Subject: [PATCH] bugfix: tolerate invalid null count when filter row groups

Signed-off-by: fangzhuhe <fangzhuhe@bytedance.com>
---
 bolt/dwio/parquet/reader/Statistics.cpp | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/bolt/dwio/parquet/reader/Statistics.cpp b/bolt/dwio/parquet/reader/Statistics.cpp
index 513abb680..70631c362 100644
--- a/bolt/dwio/parquet/reader/Statistics.cpp
+++ b/bolt/dwio/parquet/reader/Statistics.cpp
@@ -42,16 +42,20 @@ std::unique_ptr<dwio::common::ColumnStatistics> buildColumnStatisticsFromThrift(
         std::unique_ptr<NGramBloomFilter>>> nGramStats,
     const bolt::Type& type,
     uint64_t numRowsInRowGroup) {
-  std::optional<uint64_t> nullCount = columnChunkStats.__isset.null_count
-      ? std::optional<uint64_t>(columnChunkStats.null_count)
-      : std::nullopt;
-  std::optional<uint64_t> valueCount = nullCount.has_value()
-      ? std::optional<uint64_t>(numRowsInRowGroup - nullCount.value())
+  const int64_t rawNullCount = columnChunkStats.null_count;
+  const bool validNullCount = columnChunkStats.__isset.null_count &&
+      rawNullCount >= 0 &&
+      static_cast<uint64_t>(rawNullCount) <= numRowsInRowGroup;
+
+  std::optional<uint64_t> nullCount = validNullCount
+      ? std::optional<uint64_t>(static_cast<uint64_t>(rawNullCount))
       : std::nullopt;
-  std::optional<bool> hasNull = columnChunkStats.__isset.null_count
-      ? std::optional<bool>(columnChunkStats.null_count > 0)
+  std::optional<uint64_t> valueCount = validNullCount
+      ? std::optional<uint64_t>(
+            numRowsInRowGroup - static_cast<uint64_t>(rawNullCount))
       : std::nullopt;
-
+  std::optional<bool> hasNull =
+      validNullCount ? std::optional<bool>(rawNullCount > 0) : std::nullopt;
   switch (type.kind()) {
     case TypeKind::BOOLEAN:
       return std::make_unique<dwio::common::BooleanColumnStatistics>(