add config _enable_choose_migration_source_policy and choose_migration_source_policy in master code

src/share/config/ob_config_helper.cpp

@@ -1149,5 +1149,12 @@ bool ObConfigTableStoreFormatChecker::check(const ObConfigItem &t) const {
       0 == tmp_str.case_compare("COMPOUND");
 }
 
+bool ObConfigMigrationChooseSourceChecker::check(const ObConfigItem &t) const
+{
+  ObString v_str(t.str());
+  return 0 == v_str.case_compare("idc")
+      || 0 == v_str.case_compare("region");
+}
+
 } // end of namepace common
 } // end of namespace oceanbase

src/share/config/ob_config_helper.h

@@ -731,6 +731,17 @@ private:
   DISALLOW_COPY_AND_ASSIGN(ObConfigTableStoreFormatChecker);
 };
 
+class ObConfigMigrationChooseSourceChecker
+  : public ObConfigChecker
+{
+public:
+  ObConfigMigrationChooseSourceChecker() {}
+  virtual ~ObConfigMigrationChooseSourceChecker() {}
+  bool check(const ObConfigItem &t) const;
+private:
+  DISALLOW_COPY_AND_ASSIGN(ObConfigMigrationChooseSourceChecker);
+};
+
 typedef __ObConfigContainer<ObConfigStringKey,
                             ObConfigItem, OB_MAX_CONFIG_NUMBER> ObConfigContainer;
 } // namespace common

src/share/parameter/ob_parameter_seed.ipp

@@ -1871,3 +1871,12 @@ DEF_TIME(_faststack_min_interval, OB_CLUSTER_PARAMETER, "30m", "[1s,)",
         "Minimum interval for OBServer to automatically collect the obstack. "
         "Default: 30min. Range: [1s,+∞)",
         ObParameterAttr(Section::OBSERVER, Source::DEFAULT, EditLevel::DYNAMIC_EFFECTIVE));
+DEF_STR_WITH_CHECKER(choose_migration_source_policy, OB_TENANT_PARAMETER, "idc",
+        common::ObConfigMigrationChooseSourceChecker,
+        "the policy of choose source in migration and add replica. 'idc' means firstly choose follower replica of the same idc as source, "
+        "'region' means firstly choose follower replica of the same region as source",
+        ObParameterAttr(Section::TENANT, Source::DEFAULT, EditLevel::DYNAMIC_EFFECTIVE));
+DEF_BOOL(_enable_choose_migration_source_policy, OB_TENANT_PARAMETER, "True",
+        "Control whether to use chose_migration_source_policy. "
+        "If the value of configure is false, it will not use chose_migration_source_policy and choose replica with the largest checkpoint scn as the source.",
+        ObParameterAttr(Section::TENANT, Source::DEFAULT, EditLevel::DYNAMIC_EFFECTIVE));