diff --git a/src/storage/blocksstable/cs_encoding/ob_column_encoding_struct.h b/src/storage/blocksstable/cs_encoding/ob_column_encoding_struct.h
index e2ad100d5..685819efc 100644
--- a/src/storage/blocksstable/cs_encoding/ob_column_encoding_struct.h
+++ b/src/storage/blocksstable/cs_encoding/ob_column_encoding_struct.h
@@ -313,7 +313,7 @@ struct ObColumnCSEncodingCtx
   int64_t dict_var_data_size_;
   int64_t fix_data_size_;
   int64_t max_string_size_;
-  const ObPodFix2dArray<ObDatum, 1 << 20, common::OB_MALLOC_MIDDLE_BLOCK_SIZE> *col_datums_;
+  const ObPodFix2dArray<ObDatum, 1 << 20, common::OB_MALLOC_NORMAL_BLOCK_SIZE> *col_datums_;
   ObEncodingHashTable *ht_;
   const ObMicroBlockEncodingCtx *encoding_ctx_;
   ObMicroBufferWriter *all_string_buf_writer_;
diff --git a/src/storage/blocksstable/cs_encoding/ob_cs_encoding_util.cpp b/src/storage/blocksstable/cs_encoding/ob_cs_encoding_util.cpp
index 748562485..97f31f723 100644
--- a/src/storage/blocksstable/cs_encoding/ob_cs_encoding_util.cpp
+++ b/src/storage/blocksstable/cs_encoding/ob_cs_encoding_util.cpp
@@ -22,7 +22,7 @@ namespace blocksstable
 using namespace common;
 
 const int64_t ObCSEncodingUtil::ENCODING_ROW_COUNT_THRESHOLD = 4;
-// limit by typedef ObPodFix2dArray<ObDatum, 1 << 20, common::OB_MALLOC_MIDDLE_BLOCK_SIZE> ObColDatums;
+// limit by typedef ObPodFix2dArray<ObDatum, 1 << 20, common::OB_MALLOC_NORMAL_BLOCK_SIZE> ObColDatums;
 const int64_t ObCSEncodingUtil::MAX_MICRO_BLOCK_ROW_CNT = 1L << 20; // 1M
 const int64_t ObCSEncodingUtil::DEFAULT_DATA_BUFFER_SIZE = common::OB_DEFAULT_MACRO_BLOCK_SIZE;
 const int64_t ObCSEncodingUtil::MAX_BLOCK_ENCODING_STORE_SIZE = 2 * DEFAULT_DATA_BUFFER_SIZE;
diff --git a/src/storage/blocksstable/cs_encoding/ob_micro_block_cs_encoder.cpp b/src/storage/blocksstable/cs_encoding/ob_micro_block_cs_encoder.cpp
index 97df8d589..1694c63ae 100644
--- a/src/storage/blocksstable/cs_encoding/ob_micro_block_cs_encoder.cpp
+++ b/src/storage/blocksstable/cs_encoding/ob_micro_block_cs_encoder.cpp
@@ -85,6 +85,7 @@ ObMicroBlockCSEncoder::ObMicroBlockCSEncoder()
   : allocator_("CSEncAlloc", OB_MALLOC_MIDDLE_BLOCK_SIZE),
     ctx_(), row_buf_holder_(), data_buffer_(), all_string_data_buffer_(),
     all_col_datums_(OB_MALLOC_NORMAL_BLOCK_SIZE, ModulePageAllocator("CSBlkEnc", MTL_ID())),
+    pivot_allocator_(lib::ObMemAttr(MTL_ID(), blocksstable::OB_ENCODING_LABEL_PIVOT), OB_MALLOC_MIDDLE_BLOCK_SIZE),
     datum_row_offset_arr_(OB_MALLOC_NORMAL_BLOCK_SIZE, ModulePageAllocator("CSBlkEnc", MTL_ID())),
     estimate_size_(0), estimate_size_limit_(0), all_headers_size_(0),
     expand_pct_(DEFAULT_ESTIMATE_REAL_SIZE_PCT),
@@ -186,9 +187,13 @@ void ObMicroBlockCSEncoder::reset()
   FOREACH(cv, all_col_datums_)
   {
     ObColDatums *p = *cv;
-    OB_DELETE(ObColDatums, blocksstable::OB_ENCODING_LABEL_PIVOT, p);
+    if (nullptr != p) {
+      p->~ObColDatums();
+      pivot_allocator_.free(p);
+    }
   }
   all_col_datums_.reset();
+  pivot_allocator_.reset();
   datum_row_offset_arr_.reset();
   estimate_size_ = 0;
   estimate_size_limit_ = 0;
@@ -217,6 +222,7 @@ void ObMicroBlockCSEncoder::reuse()
   {
     (*c)->reuse();
   }
+  // pivot_allocator_  pivot array memory is cached until encoder reset()
   row_buf_holder_.reuse();
   all_string_data_buffer_.reuse();
   datum_row_offset_arr_.reuse();
@@ -289,13 +295,16 @@ int ObMicroBlockCSEncoder::init_all_col_values_(const ObMicroBlockEncodingCtx &c
     LOG_WARN("reserve array failed", K(ret), "size", ctx.column_cnt_);
   }
   for (int64_t i = all_col_datums_.count(); i < ctx.column_cnt_ && OB_SUCC(ret); ++i) {
-    ObColDatums *c = OB_NEW(ObColDatums, blocksstable::OB_ENCODING_LABEL_PIVOT);
+    ObColDatums *c = OB_NEWx(ObColDatums, &pivot_allocator_, pivot_allocator_);
     if (OB_ISNULL(c)) {
       ret = OB_ALLOCATE_MEMORY_FAILED;
       LOG_WARN("alloc memory failed", K(ret), K(ctx));
     } else if (OB_FAIL(all_col_datums_.push_back(c))) {
       LOG_WARN("push back column values failed", K(ret));
-      OB_DELETE(ObColDatums, blocksstable::OB_ENCODING_LABEL_PIVOT, c);
+      if (nullptr != c) {
+        c->~ObColDatums();
+        pivot_allocator_.free(c);
+      }
     }
   }
   return ret;
diff --git a/src/storage/blocksstable/cs_encoding/ob_micro_block_cs_encoder.h b/src/storage/blocksstable/cs_encoding/ob_micro_block_cs_encoder.h
index ca17bcb32..594e0ec46 100644
--- a/src/storage/blocksstable/cs_encoding/ob_micro_block_cs_encoder.h
+++ b/src/storage/blocksstable/cs_encoding/ob_micro_block_cs_encoder.h
@@ -125,6 +125,7 @@ private:
   ObMicroBufferWriter all_string_data_buffer_;
 
   common::ObArray<ObColDatums *> all_col_datums_;
+  ObArenaAllocator pivot_allocator_;
   common::ObSEArray<uint32_t, 512> datum_row_offset_arr_;
   int64_t estimate_size_;
   int64_t estimate_size_limit_;
diff --git a/src/storage/blocksstable/encoding/ob_encoding_util.h b/src/storage/blocksstable/encoding/ob_encoding_util.h
index 3f13844f1..876c445f9 100644
--- a/src/storage/blocksstable/encoding/ob_encoding_util.h
+++ b/src/storage/blocksstable/encoding/ob_encoding_util.h
@@ -660,7 +660,11 @@ private:
   const static int64_t BLOCK_ITEM_CNT = BLOCK_SIZE / sizeof(T);
   const static int64_t MAX_BLOCK_CNT = (MAX_COUNT + BLOCK_ITEM_CNT - 1) / BLOCK_ITEM_CNT;
 public:
-  ObPodFix2dArray() : size_(0) { MEMSET(block_list_, 0, sizeof(T *) * MAX_BLOCK_CNT); }
+  explicit ObPodFix2dArray(ObIAllocator &allocator)
+    : allocator_(&allocator), size_(0)
+  {
+    MEMSET(block_list_, 0, sizeof(T *) * MAX_BLOCK_CNT);
+  }
   ~ObPodFix2dArray() { destroy(); }
 
   OB_INLINE int64_t count() const { return size_; }
@@ -702,7 +706,7 @@ public:
       if (NULL == block_list_[i]) {
         break;
       } else {
-        common::ob_free(block_list_[i]);
+        allocator_->free(block_list_[i]);
         block_list_[i] = NULL;
       }
     }
@@ -739,11 +743,10 @@ private:
       ret = common::OB_SIZE_OVERFLOW;
       STORAGE_LOG(WARN, "size will overflow", K(ret), K_(size), K(block_cnt), K(cur_cnt));
     } else {
-      common::ObMemAttr ma(MTL_ID(), blocksstable::OB_ENCODING_LABEL_PIVOT);
       for (int64_t i = 0; i < block_cnt && OB_SUCC(ret); ++i) {
         if (NULL == block_list_[cur_cnt + i]) {
-          T *block = static_cast<T *>(common::ob_malloc(BLOCK_SIZE, ma));
-          if (NULL == block) {
+          T *block = static_cast<T *>(allocator_->alloc(BLOCK_SIZE));
+          if (OB_ISNULL(block)) {
             ret = common::OB_ALLOCATE_MEMORY_FAILED;
             STORAGE_LOG(WARN, "alloc block failed",
                 K(ret), "block_size", static_cast<int64_t>(BLOCK_SIZE));
@@ -756,12 +759,12 @@ private:
     return ret;
   }
 private:
+  ObIAllocator *allocator_;
   T *block_list_[MAX_BLOCK_CNT];
   int64_t size_;
 };
 
-typedef ObPodFix2dArray<common::ObObj, 64 << 10, common::OB_MALLOC_MIDDLE_BLOCK_SIZE> ObColValues;
-typedef ObPodFix2dArray<ObDatum, 1 << 20, common::OB_MALLOC_MIDDLE_BLOCK_SIZE> ObColDatums;
+typedef ObPodFix2dArray<ObDatum, 1 << 20, common::OB_MALLOC_NORMAL_BLOCK_SIZE> ObColDatums;
 
 class ObMapAttrOperator
 {
diff --git a/src/storage/blocksstable/encoding/ob_micro_block_encoder.cpp b/src/storage/blocksstable/encoding/ob_micro_block_encoder.cpp
index 156a34e61..4d9181e79 100644
--- a/src/storage/blocksstable/encoding/ob_micro_block_encoder.cpp
+++ b/src/storage/blocksstable/encoding/ob_micro_block_encoder.cpp
@@ -96,6 +96,7 @@ ObMicroBlockEncoder::ObMicroBlockEncoder() : ctx_(), header_(NULL),
     data_buffer_(),
     datum_rows_(OB_MALLOC_NORMAL_BLOCK_SIZE, MICRO_BLOCK_PAGE_ALLOCATOR),
     all_col_datums_(OB_MALLOC_NORMAL_BLOCK_SIZE, MICRO_BLOCK_PAGE_ALLOCATOR),
+    pivot_allocator_(lib::ObMemAttr(MTL_ID(), blocksstable::OB_ENCODING_LABEL_PIVOT), OB_MALLOC_MIDDLE_BLOCK_SIZE),
     estimate_size_(0), estimate_size_limit_(0),
     header_size_(0), expand_pct_(DEFAULT_ESTIMATE_REAL_SIZE_PCT),
     row_buf_holder_(),
@@ -210,9 +211,13 @@ void ObMicroBlockEncoder::reset()
   datum_rows_.reset();
   FOREACH(cv, all_col_datums_) {
     ObColDatums *p = *cv;
-    OB_DELETE(ObColDatums, blocksstable::OB_ENCODING_LABEL_PIVOT, p);
+    if (nullptr != p) {
+      p->~ObColDatums();
+      pivot_allocator_.free(p);
+    }
   }
   all_col_datums_.reset();
+  pivot_allocator_.reset();
   estimate_size_ = 0;
   estimate_size_limit_ = 0;
   header_size_ = 0;
@@ -242,6 +247,7 @@ void ObMicroBlockEncoder::reuse()
   FOREACH(c, all_col_datums_) {
     (*c)->reuse();
   }
+  // pivot_allocator_  pivot array memory is cached until encoder reset()
   row_buf_holder_.reuse();
   estimate_size_ = 0;
   // estimate_size_limit_
@@ -312,15 +318,17 @@ int ObMicroBlockEncoder::init_all_col_values(const ObMicroBlockEncodingCtx &ctx)
   if (OB_FAIL(all_col_datums_.reserve(ctx.column_cnt_))) {
     LOG_WARN("reserve array failed", K(ret), "size", ctx.column_cnt_);
   }
-  lib::ObMemAttr attr(MTL_ID(), blocksstable::OB_ENCODING_LABEL_PIVOT);
   for (int64_t i = all_col_datums_.count(); i < ctx.column_cnt_ && OB_SUCC(ret); ++i) {
-    ObColDatums *c = OB_NEW(ObColDatums, attr);
+    ObColDatums *c = OB_NEWx(ObColDatums, &pivot_allocator_, pivot_allocator_);
     if (OB_ISNULL(c)) {
       ret = OB_ALLOCATE_MEMORY_FAILED;
       LOG_WARN("alloc memory failed", K(ret), K(ctx));
     } else if (OB_FAIL(all_col_datums_.push_back(c))) {
       LOG_WARN("push back column values failed", K(ret));
-      OB_DELETE(ObColDatums, attr, c);
+      if (nullptr != c) {
+        c->~ObColDatums();
+        pivot_allocator_.free(c);
+      }
     }
   }
   return ret;
diff --git a/src/storage/blocksstable/encoding/ob_micro_block_encoder.h b/src/storage/blocksstable/encoding/ob_micro_block_encoder.h
index 776bec060..d9033432a 100644
--- a/src/storage/blocksstable/encoding/ob_micro_block_encoder.h
+++ b/src/storage/blocksstable/encoding/ob_micro_block_encoder.h
@@ -154,6 +154,7 @@ private:
   ObMicroBufferWriter data_buffer_;
   ObConstDatumRowArray datum_rows_;
   common::ObArray<ObColDatums *> all_col_datums_;
+  ObArenaAllocator pivot_allocator_;
   int64_t estimate_size_;
   int64_t estimate_size_limit_;
   int64_t header_size_;
diff --git a/src/storage/blocksstable/ob_block_sstable_struct.h b/src/storage/blocksstable/ob_block_sstable_struct.h
index 99020dabd..e9d7dd9a9 100644
--- a/src/storage/blocksstable/ob_block_sstable_struct.h
+++ b/src/storage/blocksstable/ob_block_sstable_struct.h
@@ -495,7 +495,7 @@ struct ObColumnEncodingCtx
   int64_t fix_data_size_;
   int64_t max_string_size_;
   int64_t extend_value_bit_;
-  const ObPodFix2dArray<ObDatum, 1 << 20, common::OB_MALLOC_MIDDLE_BLOCK_SIZE> *col_datums_;
+  const ObPodFix2dArray<ObDatum, 1 << 20, common::OB_MALLOC_NORMAL_BLOCK_SIZE> *col_datums_;
   ObEncodingHashTable *ht_;
   ObMultiPrefixTree *prefix_tree_;
   const ObMicroBlockEncodingCtx *encoding_ctx_;
diff --git a/unittest/storage/blocksstable/cs_encoding/test_integer_stream.cpp b/unittest/storage/blocksstable/cs_encoding/test_integer_stream.cpp
index 5c6451d29..18783e5ef 100644
--- a/unittest/storage/blocksstable/cs_encoding/test_integer_stream.cpp
+++ b/unittest/storage/blocksstable/cs_encoding/test_integer_stream.cpp
@@ -283,7 +283,7 @@ public:
         K(loop), K(sizeof(T)), K(min), K(max), K(mon), K(use_null_replace_ref), K(actual_uint_width));
     ObIntegerStreamEncoderCtx ctx;
     ObCSEncodingOpt encoding_opt;
-    ObArenaAllocator alloctor;
+    ObArenaAllocator allocator;
     const ObCompressorType compress_type =  ObCompressorType::ZSTD_1_3_8_COMPRESSOR;
     ctx.meta_.width_ = actual_uint_width;
     ctx.meta_.type_ = type;
@@ -302,10 +302,10 @@ public:
     if (ctx.meta_.is_use_null_replace_value()) {
       ctx.meta_.set_null_replaced_value(null_replace_value);
     }
-    ctx.build_stream_encoder_info(has_null, false, &encoding_opt, nullptr, -1, compress_type, &alloctor);
+    ctx.build_stream_encoder_info(has_null, false, &encoding_opt, nullptr, -1, compress_type, &allocator);
 
     ObIntegerStreamEncoder encoder;
-    ObColDatums *datums = new ObColDatums();
+    ObColDatums *datums = new ObColDatums(allocator);
     datums->reserve(1 << 20);
     generate_datums<T>(datums, size, has_null, min, max, mon);
     int64_t bitmap_size = pad8(size);
diff --git a/unittest/storage/blocksstable/cs_encoding/test_string_stream.cpp b/unittest/storage/blocksstable/cs_encoding/test_string_stream.cpp
index 1fe2ca996..18d901950 100644
--- a/unittest/storage/blocksstable/cs_encoding/test_string_stream.cpp
+++ b/unittest/storage/blocksstable/cs_encoding/test_string_stream.cpp
@@ -122,6 +122,7 @@ public:
   {
     LOG_INFO("test_and_check_string_encoding", K(size), K(type), K(use_zero_len_as_null), K(has_null), K(is_fix_len),
         K(use_nullbitmap), K(all_null), K(half_null_half_empty), K(use_null_replaced_ref));
+    ObArenaAllocator local_arena;
     ObStringStreamEncoderCtx ctx;
     ObCSEncodingOpt encoding_opt;
     bool is_use_zero_len_as_null = use_zero_len_as_null;
@@ -140,7 +141,7 @@ public:
 
     ObStringStreamEncoder encoder;
     uint32_t *data = nullptr;
-    ObColDatums *datums = new ObColDatums();
+    ObColDatums *datums = new ObColDatums(local_arena);
     ASSERT_EQ(OB_SUCCESS, datums->resize(max_count));
     datums->reuse();
     if (half_null_half_empty) {
@@ -203,7 +204,7 @@ public:
     str_data.set(all_string_writer.data(), all_string_writer.length());
 
     // 3. decode str
-    ObColDatums *datums2 = new ObColDatums();
+    ObColDatums *datums2 = new ObColDatums(local_arena);
     ASSERT_EQ(OB_SUCCESS, datums2->resize(max_count));
     datums2->reuse();
     for (int64_t i = 0; i < size; i++) {
diff --git a/unittest/storage/blocksstable/encoding/test_encoding_util.cpp b/unittest/storage/blocksstable/encoding/test_encoding_util.cpp
index 0edd027ec..e4506765d 100644
--- a/unittest/storage/blocksstable/encoding/test_encoding_util.cpp
+++ b/unittest/storage/blocksstable/encoding/test_encoding_util.cpp
@@ -60,8 +60,9 @@ TEST(ObMultiDimArray_T, timestamp_with_time_zone)
 {
   // for timestamp with time zone, we need use binary_equal to build encoding hash table.
   ObEncodingHashTableBuilder hash_builder;
+  ObArenaAllocator local_arena;
   ASSERT_EQ(OB_SUCCESS, hash_builder.create(8, 8));
-  ObColDatums time_arr;
+  ObColDatums time_arr(local_arena);
   ObStorageDatum t1, t2;
 
   ObTimeZoneInfo time_zone_info1, time_zone_info2;