fix merge group by overwrite T_QUESTIONMARK leads div core

src/sql/engine/basic/ob_chunk_datum_store.h

@@ -120,7 +120,13 @@ public:
   template <typename T = ObChunkDatumStore::StoredRow>
   class LastStoredRow {
   public:
-    LastStoredRow(ObIAllocator& alloc) : store_row_(nullptr), alloc_(alloc), max_size_(0), reuse_(false)
+    LastStoredRow(ObIAllocator& alloc)
+        : store_row_(nullptr),
+          alloc_(alloc),
+          max_size_(0),
+          reuse_(false),
+          pre_alloc_row1_(nullptr),
+          pre_alloc_row2_(nullptr)
     {}
     ~LastStoredRow()
     {}
@@ -141,17 +147,31 @@ public:
         int64_t head_size = sizeof(T);
         reuse = OB_ISNULL(store_row_) ? false : reuse && (max_size_ >= row_size + head_size + extra_size);
         if (reuse && OB_NOT_NULL(store_row_)) {
+          // switch buffer for write
+          store_row_ = (store_row_ == pre_alloc_row1_ ? pre_alloc_row2_ : pre_alloc_row1_);
           buf = reinterpret_cast<char*>(store_row_);
           new_row = store_row_;
           buffer_len = max_size_;
         } else {
+          // alloc 2 buffer with same length
           buffer_len = (!reuse_ ? row_size : row_size * 2) + head_size + extra_size;
-          if (OB_ISNULL(buf = reinterpret_cast<char*>(alloc_.alloc(buffer_len)))) {
+          char* buf1 = nullptr;
+          char* buf2 = nullptr;
+          if (OB_ISNULL(buf1 = reinterpret_cast<char*>(alloc_.alloc(buffer_len)))) {
             ret = OB_ALLOCATE_MEMORY_FAILED;
             SQL_ENG_LOG(ERROR, "alloc buf failed", K(ret));
-          } else if (OB_ISNULL(new_row = new (buf) T())) {
+          } else if (OB_ISNULL(buf2 = reinterpret_cast<char*>(alloc_.alloc(buffer_len)))) {
+            ret = OB_ALLOCATE_MEMORY_FAILED;
+            SQL_ENG_LOG(ERROR, "alloc buf failed", K(ret));
+          } else if (OB_ISNULL(pre_alloc_row1_ = new (buf1) T())) {
+            ret = OB_ALLOCATE_MEMORY_FAILED;
+            SQL_ENG_LOG(ERROR, "failed to new row", K(ret));
+          } else if (OB_ISNULL(pre_alloc_row2_ = new (buf2) T())) {
             ret = OB_ALLOCATE_MEMORY_FAILED;
             SQL_ENG_LOG(ERROR, "failed to new row", K(ret));
+          } else {
+            buf = buf1;
+            new_row = pre_alloc_row1_;
           }
         }
         if (OB_SUCC(ret)) {
@@ -221,6 +241,11 @@ public:
     ObIAllocator& alloc_;
     int64_t max_size_;
     bool reuse_;
+
+  private:
+    // To avoid writing memory overwrite, alloc 2 row for alternate writing
+    T* pre_alloc_row1_;
+    T* pre_alloc_row2_;
   };
 
   template <typename T = ObChunkDatumStore::StoredRow>

src/sql/engine/join/ob_hash_join_op.cpp

@@ -1561,15 +1561,13 @@ void ObHashJoinOp::calc_cache_aware_partition_count()
   int64_t tmp_partition_cnt_per_level = max_partition_count_per_level_;
   if (total_partition_cnt > tmp_partition_cnt_per_level) {
     level1_part_count_ = part_count_;
-    OB_ASSERT(0 != level1_part_count_);
-    level1_bit_ = __builtin_ctz(level1_part_count_);
+    level1_bit_ = (0 == level1_part_count_) ? 0 : __builtin_ctz(level1_part_count_);
     level2_part_count_ = total_partition_cnt / level1_part_count_;
     level2_part_count_ =
         level2_part_count_ > tmp_partition_cnt_per_level ? tmp_partition_cnt_per_level : level2_part_count_;
   } else {
     level1_part_count_ = total_partition_cnt > part_count_ ? total_partition_cnt : part_count_;
-    OB_ASSERT(0 != level1_part_count_);
-    level1_bit_ = __builtin_ctz(level1_part_count_);
+    level1_bit_ = (0 == level1_part_count_) ? 0 : __builtin_ctz(level1_part_count_);
   }
   LOG_TRACE("partition count",
       K(total_partition_cnt),
@@ -2758,7 +2756,11 @@ int ObHashJoinOp::get_next_probe_partition()
         } else {
           // two level
           OB_ASSERT(0 != level2_part_count_);
-          int64_t level1_part_idx = (cur_full_right_partition_ >> (__builtin_ctz(level2_part_count_)));
+          int64_t leading_zero = 0;
+          if (0 != level2_part_count_) {
+            leading_zero = __builtin_ctz(level2_part_count_);
+          }
+          int64_t level1_part_idx = (cur_full_right_partition_ >> (leading_zero));
           if (level1_part_idx < dump_part_count) {
             cur_left_hist_ = &part_histograms_[cur_full_right_partition_];
             break;

src/sql/engine/join/ob_hash_join_op.h

@@ -307,13 +307,11 @@ private:
 
     void set_part_count(int64_t part_shift, int64_t level1_part_count, int64_t level2_part_count)
     {
-      OB_ASSERT(0 != level1_part_count);
-      OB_ASSERT(0 != level2_part_count);
       part_shift_ = part_shift;
       level_one_part_count_ = level1_part_count;
       level_two_part_count_ = level2_part_count;
-      level1_bit_ = __builtin_ctz(level1_part_count);
-      level2_bit_ = __builtin_ctz(level2_part_count);
+      level1_bit_ = (0 == level1_part_count) ? 0 : __builtin_ctz(level1_part_count);
+      level2_bit_ = (0 == level2_part_count) ? 0 : __builtin_ctz(level2_part_count);
     }
     bool is_valid()
     {

src/sql/optimizer/ob_logical_operator.cpp

@@ -1507,7 +1507,7 @@ int ObLogicalOperator::do_pre_traverse_operation(const TraverseOp& op, void* ctx
             //   select /*+NO_REWRITE*/ count(*) from t1 group by 1 + (select 1 > all (select 0));
             //
             if ((*e)->has_const_or_const_expr_flag() && !(*e)->has_flag(CNT_VOLATILE_CONST) &&
-                !(*e)->has_flag(IS_EXEC_PARAM)) {
+                !(*e)->has_flag(CNT_EXEC_PARAM)) {
               ObRawExpr* remove_const_expr = NULL;
               OZ(ObRawExprUtils::build_remove_const_expr(
                   get_plan()->get_optimizer_context().get_expr_factory(), *session, *e, remove_const_expr));