The das module is a placeholder for compatibility in the master branch

src/sql/das/ob_das_task.cpp

@@ -361,7 +361,74 @@ OB_SERIALIZE_MEMBER(ObIDASTaskOp,
                     related_rtdefs_,
                     related_tablet_ids_,
                     attach_ctdef_,
-                    attach_rtdef_);
+                    attach_rtdef_,
+                    das_gts_opt_info_);
+
+OB_DEF_SERIALIZE(ObDASGTSOptInfo)
+{
+  int ret = OB_SUCCESS;
+  bool serialize_specify_snapshot = specify_snapshot_ == nullptr ? false : true;
+  LST_DO_CODE(OB_UNIS_ENCODE,
+              use_specify_snapshot_,
+              isolation_level_,
+              serialize_specify_snapshot);
+  if (serialize_specify_snapshot) {
+    OB_UNIS_ENCODE(*specify_snapshot_);
+  }
+  return ret;
+}
+
+OB_DEF_DESERIALIZE(ObDASGTSOptInfo)
+{
+  int ret = OB_SUCCESS;
+  bool serialize_specify_snapshot = false;
+  LST_DO_CODE(OB_UNIS_DECODE,
+              use_specify_snapshot_,
+              isolation_level_,
+              serialize_specify_snapshot);
+  if (serialize_specify_snapshot) {
+    if (OB_FAIL(init(isolation_level_))) {
+      LOG_WARN("fail to init gts_opt_info", K(ret));
+    } else {
+      OB_UNIS_DECODE(*specify_snapshot_);
+    }
+  }
+  return ret;
+}
+
+OB_DEF_SERIALIZE_SIZE(ObDASGTSOptInfo)
+{
+  int64_t len = 0;
+  bool serialize_specify_snapshot = specify_snapshot_ == nullptr ? false : true;
+  LST_DO_CODE(OB_UNIS_ADD_LEN,
+              use_specify_snapshot_,
+              isolation_level_,
+              serialize_specify_snapshot);
+  if (serialize_specify_snapshot) {
+    OB_UNIS_ADD_LEN(*specify_snapshot_);
+  }
+  return len;
+}
+
+int ObDASGTSOptInfo::init(transaction::ObTxIsolationLevel isolation_level)
+{
+  int ret = OB_SUCCESS;
+  void *buf = nullptr;
+  void *buf2 = nullptr;
+  if (OB_ISNULL(buf = alloc_.alloc(sizeof(ObTxReadSnapshot)))) {
+    ret = OB_ALLOCATE_MEMORY_FAILED;
+    LOG_WARN("failed to allocate memory for ObTxReadSnapshot", K(ret), K(sizeof(ObTxReadSnapshot)));
+  } else if (OB_ISNULL(buf2 = alloc_.alloc(sizeof(ObTxReadSnapshot)))) {
+    ret = OB_ALLOCATE_MEMORY_FAILED;
+    LOG_WARN("failed to allocate memory for ObTxReadSnapshot", K(ret), K(sizeof(ObTxReadSnapshot)));
+  } else {
+    use_specify_snapshot_ = true;
+    isolation_level_ = isolation_level;
+    specify_snapshot_ = new(buf) ObTxReadSnapshot();
+    response_snapshot_ = new(buf2) ObTxReadSnapshot();
+  }
+  return ret;
+}
 
 ObDASTaskArg::ObDASTaskArg()
   : timeout_ts_(0),

src/sql/das/ob_das_task.h

@@ -42,6 +42,49 @@ class ObDasAggregatedTasks;
 typedef ObDLinkNode<ObIDASTaskOp*> DasTaskNode;
 typedef ObDList<DasTaskNode> DasTaskLinkedList;
 
+struct ObDASGTSOptInfo
+{
+  OB_UNIS_VERSION(1);
+public:
+  ObDASGTSOptInfo(common::ObIAllocator &alloc)
+    : alloc_(alloc),
+      use_specify_snapshot_(false),
+      isolation_level_(),
+      specify_snapshot_(nullptr),
+      response_snapshot_(nullptr)
+  {
+  }
+
+  ~ObDASGTSOptInfo()
+  {
+    if (specify_snapshot_ != nullptr) {
+      specify_snapshot_->~ObTxReadSnapshot();
+    }
+    if (response_snapshot_ != nullptr) {
+      response_snapshot_->~ObTxReadSnapshot();
+    }
+  }
+
+  int init(transaction::ObTxIsolationLevel isolation_level);
+  void set_use_specify_snapshot(bool v)
+  {
+    use_specify_snapshot_ = v;
+  }
+  bool get_use_specify_snapshot() { return use_specify_snapshot_; }
+  transaction::ObTxReadSnapshot *get_specify_snapshot() { return specify_snapshot_; }
+  transaction::ObTxReadSnapshot *get_response_snapshot() { return response_snapshot_; }
+
+  TO_STRING_KV(K_(use_specify_snapshot),
+               K_(isolation_level),
+               KPC_(specify_snapshot),
+               KPC_(response_snapshot));
+  common::ObIAllocator &alloc_; // inited by op_alloc_ in das_op
+  bool use_specify_snapshot_;
+  transaction::ObTxIsolationLevel isolation_level_;
+  transaction::ObTxReadSnapshot *specify_snapshot_; // 给task指定snapshot_version
+  transaction::ObTxReadSnapshot *response_snapshot_; // 远端或者本地获取到的snapshot信息
+};
+
 struct ObDASRemoteInfo
 {
   OB_UNIS_VERSION(1);
@@ -124,7 +167,8 @@ public:
       cur_agg_list_(nullptr),
       op_result_(nullptr),
       attach_ctdef_(nullptr),
-      attach_rtdef_(nullptr)
+      attach_rtdef_(nullptr),
+      das_gts_opt_info_(op_alloc)
   {
     das_task_node_.get_data() = this;
   }
@@ -285,6 +329,7 @@ protected:
   //rowkey merging for index merge operations, and so on.
   const ObDASBaseCtDef *attach_ctdef_;
   ObDASBaseRtDef *attach_rtdef_;
+  ObDASGTSOptInfo das_gts_opt_info_;
 };
 typedef common::ObObjStore<ObIDASTaskOp*, common::ObIAllocator&> DasTaskList;
 typedef DasTaskList::Iterator DASTaskIter;

src/sql/engine/dml/ob_table_modify_op.cpp

@@ -626,7 +626,8 @@ ObTableModifySpec::ObTableModifySpec(common::ObIAllocator &alloc,
   : ObOpSpec(alloc, type),
     expr_frame_info_(NULL),
     ab_stmt_id_(nullptr),
-    flags_(0)
+    flags_(0),
+    das_dop_(0)
 {
 }
 
@@ -636,6 +637,7 @@ OB_DEF_SERIALIZE(ObTableModifySpec)
   BASE_SER((ObTableModifySpec, ObOpSpec));
   OB_UNIS_ENCODE(flags_);
   OB_UNIS_ENCODE(ab_stmt_id_);
+  OB_UNIS_ENCODE(das_dop_);
   return ret;
 }
 
@@ -645,6 +647,7 @@ OB_DEF_DESERIALIZE(ObTableModifySpec)
   BASE_DESER((ObTableModifySpec, ObOpSpec));
   OB_UNIS_DECODE(flags_);
   OB_UNIS_DECODE(ab_stmt_id_);
+  OB_UNIS_DECODE(das_dop_);
   return ret;
 }
 
@@ -654,6 +657,7 @@ OB_DEF_SERIALIZE_SIZE(ObTableModifySpec)
   BASE_ADD_LEN((ObTableModifySpec, ObOpSpec));
   OB_UNIS_ADD_LEN(flags_);
   OB_UNIS_ADD_LEN(ab_stmt_id_);
+  OB_UNIS_ADD_LEN(das_dop_);
   return len;
 }
 

src/sql/engine/dml/ob_table_modify_op.h

@@ -137,6 +137,7 @@ public:
       uint64_t reserved_                        : 55;
     };
   };
+  int64_t das_dop_; // default is 0
 private:
   DISALLOW_COPY_AND_ASSIGN(ObTableModifySpec);
 };