diff --git a/src/observer/virtual_table/ob_all_virtual_dtl_first_cached_buffer.cpp b/src/observer/virtual_table/ob_all_virtual_dtl_first_cached_buffer.cpp
index ac1a90f45..e583e6e2c 100644
--- a/src/observer/virtual_table/ob_all_virtual_dtl_first_cached_buffer.cpp
+++ b/src/observer/virtual_table/ob_all_virtual_dtl_first_cached_buffer.cpp
@@ -88,9 +88,9 @@ class ObAllVirtualDtlFirstCachedBufferPoolOp {
 public:
   class ObDtlFirstBufferHashMapOp {
   public:
-    ObDtlFirstBufferHashMapOp(int64_t max_cnt, int64_t tenant_id,
+    ObDtlFirstBufferHashMapOp(int64_t tenant_id,
         ObArray<ObAllVirtualDtlFirstBufferInfo, ObWrapperAllocator>* first_buffer_info)
-        : max_cnt_(max_cnt), tenant_id_(tenant_id), first_buffer_infos_(first_buffer_info)
+        : tenant_id_(tenant_id), first_buffer_infos_(first_buffer_info)
     {}
     ~ObDtlFirstBufferHashMapOp()
     {
@@ -109,7 +109,6 @@ public:
     }
 
   private:
-    int64_t max_cnt_;
     int64_t tenant_id_;
     ObArray<ObAllVirtualDtlFirstBufferInfo, ObWrapperAllocator>* first_buffer_infos_;
   };
@@ -126,8 +125,8 @@ public:
   int operator()(ObDtlLocalFirstBufferCache* buffer_cache)
   {
     int ret = OB_SUCCESS;
-    ObDtlFirstBufferHashTable<uint64_t, ObDtlCacheBufferInfo>& buffer_map = buffer_cache->get_buffer_map();
-    ObDtlFirstBufferHashMapOp op(MAX_BUFFER_CNT_PER_TENANT, tenant_id_, first_buffer_infos_);
+    ObDtlFirstBufferHashTable<uint64_t, ObDtlCacheBufferInfo> &buffer_map = buffer_cache->get_buffer_map();
+    ObDtlFirstBufferHashMapOp op(tenant_id_, first_buffer_infos_);
     if (OB_FAIL(buffer_map.foreach_refactored(op))) {
       LOG_WARN("failed to get channel memory manager", K(ret));
     }
diff --git a/src/sql/dtl/ob_dtl_channel_group.h b/src/sql/dtl/ob_dtl_channel_group.h
index 5979b5c90..d53b8c1b4 100644
--- a/src/sql/dtl/ob_dtl_channel_group.h
+++ b/src/sql/dtl/ob_dtl_channel_group.h
@@ -24,7 +24,7 @@ namespace dtl {
 class ObDtlTask;
 class ObDtlChannel;
 class ObDtlChSet;
-class ObDtlChannelInfo;
+struct ObDtlChannelInfo;
 class ObDtlFlowControl;
 
 // Channel group is a bunch of channels than support communication
diff --git a/src/sql/dtl/ob_dtl_fc_server.cpp b/src/sql/dtl/ob_dtl_fc_server.cpp
index 0662e427c..db1e239c7 100644
--- a/src/sql/dtl/ob_dtl_fc_server.cpp
+++ b/src/sql/dtl/ob_dtl_fc_server.cpp
@@ -410,8 +410,7 @@ void ObDfcServer::runTimerTask()
   {
     ObLockGuard<ObSpinLock> lock_guard(lock_);
     for (DfcHashMapIterator iter = tenant_dfc_map_.begin(); iter != tenant_dfc_map_.end(); ++iter) {
-      uint64_t tenant_id = iter->first;
-      ObTenantDfc* dfc = iter->second;
+      ObTenantDfc *dfc = iter->second;
       if (OB_ISNULL(dfc)) {
         LOG_WARN("null ptr, unexpected. ignore this tenant and continue", K(ret));
       } else if (OB_FAIL(dfc_list.push_back(dfc))) {
diff --git a/src/sql/dtl/ob_dtl_linked_buffer.h b/src/sql/dtl/ob_dtl_linked_buffer.h
index 1e265ff1b..062063f48 100644
--- a/src/sql/dtl/ob_dtl_linked_buffer.h
+++ b/src/sql/dtl/ob_dtl_linked_buffer.h
@@ -22,7 +22,7 @@ namespace dtl {
 
 #define DTL_BROADCAST (1ULL)
 
-class ObDtlMsgHeader;
+struct ObDtlMsgHeader;
 class ObDtlChannel;
 
 class ObDtlDfoKey {
diff --git a/src/sql/engine/aggregate/ob_hash_distinct.cpp b/src/sql/engine/aggregate/ob_hash_distinct.cpp
index 4013c34bc..58d3a6544 100644
--- a/src/sql/engine/aggregate/ob_hash_distinct.cpp
+++ b/src/sql/engine/aggregate/ob_hash_distinct.cpp
@@ -839,7 +839,6 @@ int ObHashDistinct::ObHashDistinctCtx::get_dist_row_from_in_mem_partitions(
   ObNewRow* cur_row = NULL;
   uint64_t hash_value = 0;
   uint64_t bucket_idx = 0;
-  ObChunkRowStore* store;
   if (first_read_part_) {
     first_read_part_ = false;
     if (OB_FAIL(get_next_mem_partition())) {
diff --git a/src/sql/engine/basic/ob_pushdown_filter.h b/src/sql/engine/basic/ob_pushdown_filter.h
index d0d62bda9..6e3cc890c 100644
--- a/src/sql/engine/basic/ob_pushdown_filter.h
+++ b/src/sql/engine/basic/ob_pushdown_filter.h
@@ -246,7 +246,7 @@ public:
         col_params_(nullptr),
         allocator_(alloc)
   {}
-  ~ObPushdownFilterExecutor()
+  virtual ~ObPushdownFilterExecutor()
   {
     if (nullptr != filter_bitmap_) {
       filter_bitmap_->~ObBitmap();
@@ -471,7 +471,7 @@ private:
 
 class ObFilterExecutorConstructor {
 public:
-  ObFilterExecutorConstructor(common::ObIAllocator* alloc) : alloc_(alloc), factory_(alloc)
+  ObFilterExecutorConstructor(common::ObIAllocator* alloc) : factory_(alloc)
   {}
   int apply(ObPushdownFilterNode* filter_tree, ObPushdownFilterExecutor*& filter_executor);
 
@@ -480,7 +480,6 @@ private:
   int create_filter_executor(ObPushdownFilterNode* filter_tree, ObPushdownFilterExecutor*& filter_executor);
 
 private:
-  common::ObIAllocator* alloc_;
   ObPushdownFilterFactory factory_;
 };
 
diff --git a/src/sql/engine/join/ob_hj_batch.h b/src/sql/engine/join/ob_hj_batch.h
index 5fef188d5..3a8b15a43 100644
--- a/src/sql/engine/join/ob_hj_batch.h
+++ b/src/sql/engine/join/ob_hj_batch.h
@@ -21,19 +21,17 @@ namespace oceanbase {
 namespace sql {
 namespace join {
 
-class ObStoredJoinRow;
+struct ObStoredJoinRow;
 class ObHJBatch {
 public:
-  ObHJBatch(common::ObIAllocator& alloc, ObHJBufMgr* buf_mgr, uint64_t tenant_id, int32_t part_level, int32_t batchno)
-      : alloc_(alloc),
-        chunk_row_store_(&alloc),
+  ObHJBatch(common::ObIAllocator &alloc, ObHJBufMgr *buf_mgr, uint64_t tenant_id, int32_t part_level, int32_t batchno)
+      : chunk_row_store_(&alloc),
         inner_callback_(nullptr),
         part_level_(part_level),
         batchno_(batchno),
         is_chunk_iter_(false),
         buf_mgr_(buf_mgr),
         tenant_id_(tenant_id),
-        timeout_ms_(1000000),
         n_get_rows_(0),
         n_add_rows_(0),
         pre_total_size_(0),
@@ -159,8 +157,6 @@ public:
   }
 
 private:
-  const int64_t ROW_CNT_PER = 0x3FF;
-  common::ObIAllocator& alloc_;
   sql::ObChunkRowStore chunk_row_store_;
   sql::ObChunkRowStore::RowIterator row_store_iter_;
   sql::ObChunkRowStore::ChunkIterator chunk_iter_;
@@ -170,7 +166,6 @@ private:
   bool is_chunk_iter_;
   ObHJBufMgr* buf_mgr_;
   uint64_t tenant_id_;
-  int64_t timeout_ms_;
   int64_t n_get_rows_;
   int64_t n_add_rows_;
 
diff --git a/src/sql/engine/join/ob_hj_buf_mgr.h b/src/sql/engine/join/ob_hj_buf_mgr.h
index d594d910a..ca09c5c8a 100644
--- a/src/sql/engine/join/ob_hj_buf_mgr.h
+++ b/src/sql/engine/join/ob_hj_buf_mgr.h
@@ -22,23 +22,13 @@ namespace join {
 
 class ObHJBufMgr : public ObSqlMemoryCallback {
 public:
-  ObHJBufMgr()
-      : reserve_memory_size_(0),
-        pre_total_alloc_size_(0),
-        total_alloc_size_(0),
-        total_left_alloc_size_(0),
-        page_size_(-1),
-        dumped_size_(0)
+  ObHJBufMgr() :
+    reserve_memory_size_(0), pre_total_alloc_size_(0), total_alloc_size_(0),
+    page_size_(-1), dumped_size_(0)
   {}
 
-  inline void set_page_size(int64_t page_size)
-  {
-    page_size_ = page_size;
-  }
-  inline int64_t get_page_size()
-  {
-    return page_size_;
-  }
+  inline void set_page_size(int64_t page_size) { page_size_ = page_size; }
+  inline int64_t get_page_size() { return page_size_; }
 
   void set_reserve_memory_size(int64_t reserve_memory_size)
   {
@@ -86,8 +76,6 @@ public:
     return reserve_memory_size_ < page_size_ + total_alloc_size_;
   }
 
-  // OB_INLINE void finish_left_dump() { total_left_alloc_size_ = total_alloc_size_; }
-
   OB_INLINE bool need_dump()
   {
     return reserve_memory_size_ * RATIO / 100 < total_alloc_size_;
@@ -98,7 +86,6 @@ private:
   int64_t reserve_memory_size_;
   int64_t pre_total_alloc_size_;
   int64_t total_alloc_size_;
-  int64_t total_left_alloc_size_;
   int64_t page_size_;
   int64_t dumped_size_;
 };
diff --git a/src/sql/engine/ob_physical_plan_ctx.h b/src/sql/engine/ob_physical_plan_ctx.h
index 4fcf3dd0b..acd3cc7d7 100644
--- a/src/sql/engine/ob_physical_plan_ctx.h
+++ b/src/sql/engine/ob_physical_plan_ctx.h
@@ -30,7 +30,7 @@ class ObSQLSessionInfo;
 class ObPhysicalPlan;
 class ObExecContext;
 class ObUdfCtxMgr;
-class ObPxDmlRowInfo;
+struct ObPxDmlRowInfo;
 
 struct PartParamIdxArray {
   PartParamIdxArray() : part_id_(-1), part_param_idxs_()
diff --git a/src/sql/engine/px/exchange/ob_px_receive_op.cpp b/src/sql/engine/px/exchange/ob_px_receive_op.cpp
index d95944653..e55978867 100644
--- a/src/sql/engine/px/exchange/ob_px_receive_op.cpp
+++ b/src/sql/engine/px/exchange/ob_px_receive_op.cpp
@@ -254,9 +254,6 @@ int ObPxReceiveOp::rescan()
 int ObPxReceiveOp::drain_exch()
 {
   int ret = OB_SUCCESS;
-  int tmp_ret = OB_SUCCESS;
-  const ObNewRow* row = NULL;
-  ObPxReceiveOpInput* recv_input = NULL;
   uint64_t version = -1;
   if (OB_FAIL(try_open())) {
     LOG_WARN("get operator ctx failed", K(ret));
@@ -296,7 +293,6 @@ int ObPxReceiveOp::drain_exch()
 int ObPxReceiveOp::active_all_receive_channel()
 {
   int ret = OB_SUCCESS;
-  const int batch = 10;
   while (!dfc_.is_all_channel_act() && OB_SUCC(ret)) {
     if (OB_FAIL(inner_get_next_row())) {
       if (OB_ITER_END != ret) {
diff --git a/src/sql/engine/px/exchange/ob_px_transmit_op.cpp b/src/sql/engine/px/exchange/ob_px_transmit_op.cpp
index 6f677bf31..c6172912c 100644
--- a/src/sql/engine/px/exchange/ob_px_transmit_op.cpp
+++ b/src/sql/engine/px/exchange/ob_px_transmit_op.cpp
@@ -61,8 +61,7 @@ int ObPxTransmitOpInput::get_parent_dfo_key(ObDtlDfoKey& key)
 int ObPxTransmitOpInput::get_data_ch(ObPxTaskChSet& task_ch_set, int64_t timeout_ts, ObDtlChTotalInfo*& ch_info)
 {
   int ret = OB_SUCCESS;
-  int64_t task_id = OB_INVALID_ID;
-  ObPxSQCProxy* ch_provider = reinterpret_cast<ObPxSQCProxy*>(ch_provider_ptr_);
+  ObPxSQCProxy* ch_provider = reinterpret_cast<ObPxSQCProxy *>(ch_provider_ptr_);
   if (OB_ISNULL(ch_provider)) {
     ret = OB_NOT_INIT;
     LOG_WARN("ch provider not init", K(ret));
@@ -341,7 +340,6 @@ int ObPxTransmitOp::send_eof_row()
   int ret = OB_SUCCESS;
   ObPhysicalPlanCtx* phy_plan_ctx = GET_PHY_PLAN_CTX(ctx_);
   LOG_TRACE("Send eof row", "op_id", get_spec().id_, "ch_cnt", task_channels_.count(), K(ret));
-  int64_t max_loop = 0;
   if (OB_ISNULL(ch_info_) || ch_info_->receive_exec_server_.total_task_cnt_ != task_channels_.count()) {
     ret = OB_ERR_UNEXPECTED;
     LOG_WARN("unexpected status: ch info is null", K(ret), KP(ch_info_), K(task_channels_.count()));
diff --git a/src/sql/engine/px/ob_px_data_ch_provider.cpp b/src/sql/engine/px/ob_px_data_ch_provider.cpp
index 9b36de980..527047aa0 100644
--- a/src/sql/engine/px/ob_px_data_ch_provider.cpp
+++ b/src/sql/engine/px/ob_px_data_ch_provider.cpp
@@ -80,7 +80,6 @@ int ObPxChProviderUtil::inner_get_data_ch(bool ch_map_opt, ObPxTaskChSets& ch_se
     // transmit get channel
     // M: transmit task count
     // N: receive task count
-    uint64_t chid = 0;
     if (is_transmit) {
       // transmit
       if (OB_FAIL(ObDtlChannelUtil::get_transmit_dtl_channel_set(sqc_id, task_id, ch_total_info, ch_set))) {
diff --git a/src/sql/resolver/dml/ob_group_by_checker.cpp b/src/sql/resolver/dml/ob_group_by_checker.cpp
index d6920a758..2f41a3b23 100644
--- a/src/sql/resolver/dml/ob_group_by_checker.cpp
+++ b/src/sql/resolver/dml/ob_group_by_checker.cpp
@@ -451,7 +451,7 @@ int ObGroupByChecker::visit(ObConstRawExpr& expr)
   if (find_in_rollup(expr) || find_in_grouping_sets(expr)) {
     set_skip_expr(&expr);
   }
-  return OB_SUCCESS;
+  return ret;
 }
 
 int ObGroupByChecker::visit(ObVarRawExpr& expr)