diff --git a/src/sql/engine/sort/ob_prefix_sort_vec_op_impl.h b/src/sql/engine/sort/ob_prefix_sort_vec_op_impl.h
index ea6277c2ee..18be014bd6 100644
--- a/src/sql/engine/sort/ob_prefix_sort_vec_op_impl.h
+++ b/src/sql/engine/sort/ob_prefix_sort_vec_op_impl.h
@@ -55,10 +55,10 @@ protected:
 
   LST_DO_CODE(USING_SORT_IMPL, init, is_inited, add_batch, get_next_batch,
               get_next_batch_stored_rows, init_temp_row_store, adjust_topn_read_rows, attach_rows,
-              allocator_, eval_ctx_, cmp_sk_exprs_, sk_exprs_, all_exprs_, addon_exprs_,
-              addon_vec_ptrs_, sk_vec_ptrs_, comp_, part_cnt_, topn_cnt_, outputted_rows_cnt_,
-              cmp_sort_collations_, exec_ctx_, enable_encode_sortkey_, sk_rows_, addon_rows_,
-              sk_store_, addon_store_, sk_row_meta_, addon_row_meta_);
+              allocator_, mem_context_, eval_ctx_, cmp_sk_exprs_, sk_exprs_, all_exprs_,
+              addon_exprs_, addon_vec_ptrs_, sk_vec_ptrs_, comp_, part_cnt_, topn_cnt_,
+              outputted_rows_cnt_, cmp_sort_collations_, exec_ctx_, enable_encode_sortkey_,
+              sk_rows_, addon_rows_, sk_store_, addon_store_, sk_row_meta_, addon_row_meta_);
 
   // fetch rows in same prefix && do sort, set %next_prefix_row_ to nullptr
   // when all child rows are fetched.
diff --git a/src/sql/engine/sort/ob_prefix_sort_vec_op_impl.ipp b/src/sql/engine/sort/ob_prefix_sort_vec_op_impl.ipp
index a8c0c06bb3..4c898c3192 100644
--- a/src/sql/engine/sort/ob_prefix_sort_vec_op_impl.ipp
+++ b/src/sql/engine/sort/ob_prefix_sort_vec_op_impl.ipp
@@ -31,10 +31,20 @@ void ObPrefixSortVecImpl<Compare, Store_Row, has_addon>::reset()
   prefix_pos_ = 0;
   im_sk_store_.reset();
   im_addon_store_.reset();
-  im_sk_rows_ = nullptr;
-  im_addon_rows_ = nullptr;
   immediate_pos_ = 0;
   brs_ = nullptr;
+  if (nullptr != mem_context_ && nullptr != selector_) {
+    mem_context_->get_malloc_allocator().free(selector_);
+    selector_ = nullptr;
+  }
+  if (nullptr != mem_context_ && nullptr != im_sk_rows_) {
+    mem_context_->get_malloc_allocator().free(im_sk_rows_);
+    im_sk_rows_ = nullptr;
+  }
+  if (nullptr != mem_context_ && nullptr != im_addon_rows_) {
+    mem_context_->get_malloc_allocator().free(im_addon_rows_);
+    im_addon_rows_ = nullptr;
+  }
   ObSortVecOpImpl<Compare, Store_Row, has_addon>::reset();
 }
 
@@ -80,10 +90,10 @@ int ObPrefixSortVecImpl<Compare, Store_Row, has_addon>::init(ObSortVecOpContext
       SQL_ENG_LOG(WARN, "failed to init temp row store", K(ret));
     } else {
       selector_ =
-        (typeof(selector_))ctx.exec_ctx_->get_allocator().alloc(batch_size * sizeof(*selector_));
-      im_sk_rows_ = (typeof(im_sk_rows_))ctx.exec_ctx_->get_allocator().alloc(
+        (typeof(selector_))mem_context_->get_malloc_allocator().alloc(batch_size * sizeof(*selector_));
+      im_sk_rows_ = (typeof(im_sk_rows_))mem_context_->get_malloc_allocator().alloc(
         batch_size * sizeof(*im_sk_rows_));
-      im_addon_rows_ = (typeof(im_addon_rows_))ctx.exec_ctx_->get_allocator().alloc(
+      im_addon_rows_ = (typeof(im_addon_rows_))mem_context_->get_malloc_allocator().alloc(
         batch_size * sizeof(*im_addon_rows_));
       if (nullptr == selector_ || nullptr == im_sk_rows_ || nullptr == im_addon_rows_) {
         ret = OB_ALLOCATE_MEMORY_FAILED;
diff --git a/src/sql/engine/sort/ob_sort_op_impl.cpp b/src/sql/engine/sort/ob_sort_op_impl.cpp
index 1df98411c0..d5f0e26b68 100644
--- a/src/sql/engine/sort/ob_sort_op_impl.cpp
+++ b/src/sql/engine/sort/ob_sort_op_impl.cpp
@@ -2769,10 +2769,16 @@ void ObPrefixSortImpl::reset()
   selector_size_ = 0;
   sort_prefix_rows_ = 0;
   immediate_prefix_store_.reset();
-  immediate_prefix_rows_ = 0;
   immediate_prefix_pos_ = 0;
   brs_ = NULL;
-
+  if (nullptr != mem_context_ && nullptr != selector_) {
+    mem_context_->get_malloc_allocator().free(selector_);
+    selector_ = nullptr;
+  }
+  if (nullptr != mem_context_ && nullptr != immediate_prefix_rows_) {
+    mem_context_->get_malloc_allocator().free(immediate_prefix_rows_);
+    immediate_prefix_rows_ = nullptr;
+  }
   ObSortOpImpl::reset();
 }
 
@@ -2833,10 +2839,10 @@ int ObPrefixSortImpl::init(const int64_t tenant_id,
         LOG_WARN("fetch rows failed");
       }
     } else {
-      selector_ = (typeof(selector_))eval_ctx->exec_ctx_.get_allocator().alloc(
+      selector_ = (typeof(selector_))mem_context_->get_malloc_allocator().alloc(
           batch_size * sizeof(*selector_));
       immediate_prefix_rows_ = (typeof(immediate_prefix_rows_))
-          eval_ctx->exec_ctx_.get_allocator().alloc(batch_size * sizeof(*immediate_prefix_rows_));
+          mem_context_->get_malloc_allocator().alloc(batch_size * sizeof(*immediate_prefix_rows_));
       if (NULL == selector_ || NULL == immediate_prefix_rows_) {
         ret = OB_ALLOCATE_MEMORY_FAILED;
         LOG_WARN("allocate memory failed",