[CP] reset multi_version_start at restore start

src/storage/high_availability/ob_ls_restore.cpp

@@ -1063,6 +1063,8 @@ int ObStartLSRestoreTask::update_ls_meta_and_create_all_tablets_()
                      && OB_FAIL(ctx_->sys_tablet_id_array_.push_back(tablet_info.param_.tablet_id_))) {
             LOG_WARN("failed to push sys tablet id into array", K(ret), "array count", ctx_->sys_tablet_id_array_.count());
           } else if (!tablet_info.param_.is_empty_shell() && OB_FALSE_IT(set_tablet_to_restore(tablet_info.param_))) {
+          } else if (OB_FAIL(reset_multi_version_start_(tablet_info.param_))) {
+            LOG_WARN("failed to reset multi version start", K(ret), K(tablet_info));
           } else if (OB_FAIL(create_tablet_(tablet_info.param_, ls))) {
             LOG_WARN("failed to create tablet", K(ret));
           } else {
@@ -1181,6 +1183,21 @@ int ObStartLSRestoreTask::generate_tablets_restore_dag_()
   return ret;
 }
 
+int ObStartLSRestoreTask::reset_multi_version_start_(ObMigrationTabletParam &param)
+{
+  int ret = OB_SUCCESS;
+  if (!param.is_valid()) {
+    ret = OB_INVALID_ARGUMENT;
+    LOG_WARN("param is not valid", K(ret), K(param));
+  } else {
+    // We reset the multi version start of the tablet migration parameter that is backup in backup consistent SCN stage.
+    // This stage does not have any SSTables and only serves as a placeholder.
+    // So the multi version start can be reset to 0 and then pushed up in the restore minor stage and restore major stage.
+    param.multi_version_start_ = 0;
+  }
+  return ret;
+}
+
 /******************ObSysTabletsRestoreDag*********************/
 ObSysTabletsRestoreDag::ObSysTabletsRestoreDag()
   : ObLSRestoreDag(ObDagType::DAG_TYPE_SYS_TABLETS_RESTORE),

src/storage/high_availability/ob_ls_restore.h

@@ -213,6 +213,7 @@ private:
   void free_copy_ls_view_reader_(ObICopyLSViewInfoReader *&reader);
   int generate_tablet_id_array_(
       const ObIArray<common::ObTabletID> &tablet_id_array);
+  int reset_multi_version_start_(ObMigrationTabletParam &param);
 private:
   bool is_inited_;
   ObLSRestoreCtx *ctx_;