diff --git a/deps/oblib/src/rpc/obrpc/ob_rpc_packet_list.h b/deps/oblib/src/rpc/obrpc/ob_rpc_packet_list.h
index c6e7da4fd9..ce071b3514 100644
--- a/deps/oblib/src/rpc/obrpc/ob_rpc_packet_list.h
+++ b/deps/oblib/src/rpc/obrpc/ob_rpc_packet_list.h
@@ -204,6 +204,7 @@ PCODE_DEF(OB_REVOKE_SYSPRIV, 0x270)
 PCODE_DEF(OB_EXECUTE_RANGE_PART_SPLIT, 0x271)
 PCODE_DEF(OB_CLUSTER_ACTION_VERIFY, 0x273)
 PCODE_DEF(OB_SUBMIT_BUILD_INDEX_TASK, 0x274)
+PCODE_DEF(OB_FETCH_SSTABLE_SIZE, 0x275)
 
 // system admin commnad
 PCODE_DEF(OB_ADMIN_SWITCH_REPLICA_ROLE, 0x280)
diff --git a/src/observer/ob_rpc_processor_simple.cpp b/src/observer/ob_rpc_processor_simple.cpp
index 601633929f..225acb58f2 100644
--- a/src/observer/ob_rpc_processor_simple.cpp
+++ b/src/observer/ob_rpc_processor_simple.cpp
@@ -1992,5 +1992,37 @@ int ObKillPartTransCtxP::process()
   return ret;
 }
 
+int ObFetchSstableSizeP::process()
+{
+  int ret = OB_SUCCESS;
+  ObPartitionStorage *storage = NULL;
+  ObTableHandle sstable_handle;
+  ObIPartitionGroupGuard guard;
+  ObPGPartitionGuard pg_partition_guard;
+  ObSSTable *sstable = nullptr;
+  if (OB_FAIL(gctx_.par_ser_->get_partition(arg_.pkey_, guard))
+      || NULL == guard.get_partition_group()) {
+    LOG_WARN("get_partition_storage fail", "pkey", arg_);
+    ret = OB_ENTRY_NOT_EXIST;
+  } else if (OB_FAIL(guard.get_partition_group()->get_pg_partition(arg_.pkey_, pg_partition_guard))) {
+    LOG_WARN("get pg partition fail", K(ret), "pkey", arg_.pkey_);
+  } else if (OB_ISNULL(storage = static_cast<ObPartitionStorage *>
+                                 (pg_partition_guard.get_pg_partition()->get_storage()))) {
+    ret = OB_ERR_UNEXPECTED;
+    LOG_WARN("get_partition_storage fail", "pkey", arg_.pkey_);
+  } else if (OB_FAIL(storage->get_partition_store().get_last_major_sstable(arg_.index_id_, sstable_handle))) {
+    LOG_WARN("fail to get index major sstable handle", K(ret), K_(arg));
+  } else if (OB_FAIL(sstable_handle.get_sstable(sstable))) {
+    LOG_WARN("fail to get index major sstable handle", K(ret), K_(arg));
+  } else if (OB_ISNULL(sstable)) {
+    ret = OB_ERR_UNEXPECTED;
+    LOG_WARN("index sstable is null", K(ret), K_(arg));
+  } else {
+    const blocksstable::ObSSTableMeta &sstable_meta = sstable->get_meta();
+    result_.size_ = sstable_meta.get_total_macro_block_count() * OB_FILE_SYSTEM.get_macro_block_size();
+  }
+  return ret;
+}
+
 }  // end of namespace observer
 }  // end of namespace oceanbase
diff --git a/src/observer/ob_rpc_processor_simple.h b/src/observer/ob_rpc_processor_simple.h
index e859e85405..8a6b915a00 100644
--- a/src/observer/ob_rpc_processor_simple.h
+++ b/src/observer/ob_rpc_processor_simple.h
@@ -226,6 +226,8 @@ OB_DEFINE_PROCESSOR_S(Common, OB_GET_MASTER_RS, ObRpcGetMasterRSP);
 OB_DEFINE_PROCESSOR_S(Srv, OB_CHECK_PHYSICAL_FLASHBACK_SUCC, ObCheckPhysicalFlashbackSUCCP);
 OB_DEFINE_PROCESSOR_S(Srv, OB_RENEW_IN_ZONE_HB, ObRenewInZoneHbP);
 OB_DEFINE_PROCESSOR_S(Srv, OB_KILL_PART_TRANS_CTX, ObKillPartTransCtxP);
+OB_DEFINE_PROCESSOR_S(Srv, OB_FETCH_SSTABLE_SIZE, ObFetchSstableSizeP);
+
 }  // end of namespace observer
 }  // end of namespace oceanbase
 
diff --git a/src/observer/ob_srv_xlator_storage.cpp b/src/observer/ob_srv_xlator_storage.cpp
index 5de150717c..580294646c 100644
--- a/src/observer/ob_srv_xlator_storage.cpp
+++ b/src/observer/ob_srv_xlator_storage.cpp
@@ -131,4 +131,5 @@ void oceanbase::observer::init_srv_xlator_for_storage(ObSrvRpcXlator* xlator)
   RPC_PROCESSOR(ObRpcValidateBackupBatchP, gctx_);
   RPC_PROCESSOR(ObRpcBackupArchiveLogBatchP, gctx_);
   RPC_PROCESSOR(ObRpcBackupBackupsetBatchP, gctx_);
+  RPC_PROCESSOR(ObFetchSstableSizeP, gctx_);
 }
diff --git a/src/rootserver/ob_root_service.cpp b/src/rootserver/ob_root_service.cpp
index 87164b118f..b2696ddf92 100644
--- a/src/rootserver/ob_root_service.cpp
+++ b/src/rootserver/ob_root_service.cpp
@@ -7804,7 +7804,10 @@ int ObRootService::observer_copy_local_index_sstable(const obrpc::ObServerCopyLo
       } else if (OB_FAIL(rebalance_task_mgr_.add_task(task))) {
         LOG_WARN("fail to add task", K(ret), K(task));
       } else {
-        LOG_INFO("add copy local index sstable task", K(ret));
+        ROOTSERVICE_EVENT_ADD("balancer", "add_copy_sstable_task",
+                              "partition", ReplicaInfo(pkey, data_size),
+                              "source", src_member,
+                              "destination", dest_replica);
       }
     }
   }
diff --git a/src/share/ob_rpc_struct.cpp b/src/share/ob_rpc_struct.cpp
index 590f44e4d2..0d00bfe843 100755
--- a/src/share/ob_rpc_struct.cpp
+++ b/src/share/ob_rpc_struct.cpp
@@ -4939,5 +4939,30 @@ int ObSubmitBuildIndexTaskArg::assign(const ObSubmitBuildIndexTaskArg &other)
 
 OB_SERIALIZE_MEMBER((ObSubmitBuildIndexTaskArg, ObDDLArg), index_tid_);
 
+OB_SERIALIZE_MEMBER(ObFetchSstableSizeArg, pkey_, index_id_);
+
+int ObFetchSstableSizeArg::assign(const ObFetchSstableSizeArg &other)
+{
+  int ret = OB_SUCCESS;
+  if (this == &other) {
+  } else {
+    pkey_ = other.pkey_;
+    index_id_ = other.index_id_;
+  }
+  return ret;
+}
+
+OB_SERIALIZE_MEMBER(ObFetchSstableSizeRes, size_);
+
+int ObFetchSstableSizeRes::assign(const ObFetchSstableSizeRes &other)
+{
+  int ret = OB_SUCCESS;
+  if (this == &other) {
+  } else {
+    size_ = other.size_;
+  }
+  return ret;
+}
+
 }  // end namespace obrpc
 }  // namespace oceanbase
diff --git a/src/share/ob_rpc_struct.h b/src/share/ob_rpc_struct.h
index eda618ffa9..eaf19bd7aa 100755
--- a/src/share/ob_rpc_struct.h
+++ b/src/share/ob_rpc_struct.h
@@ -8346,6 +8346,47 @@ public:
   uint64_t index_tid_;
 };
 
+struct ObFetchSstableSizeArg final {
+  OB_UNIS_VERSION(1);
+
+public:
+  ObFetchSstableSizeArg() : pkey_(), index_id_(-1)
+  {}
+  ~ObFetchSstableSizeArg()
+  {}
+  bool is_valid() const
+  {
+    return pkey_.is_valid() && index_id_ > 0;
+  }
+  int assign(const ObFetchSstableSizeArg &other);
+  TO_STRING_KV(K_(pkey), K_(index_id));
+
+public:
+  common::ObPartitionKey pkey_;
+  int64_t index_id_;
+
+private:
+  DISALLOW_COPY_AND_ASSIGN(ObFetchSstableSizeArg);
+};
+
+struct ObFetchSstableSizeRes final {
+  OB_UNIS_VERSION(1);
+
+public:
+  ObFetchSstableSizeRes() : size_(0)
+  {}
+  ~ObFetchSstableSizeRes()
+  {}
+  int assign(const ObFetchSstableSizeRes &other);
+  TO_STRING_KV(K_(size));
+
+public:
+  int64_t size_;
+
+private:
+  DISALLOW_COPY_AND_ASSIGN(ObFetchSstableSizeRes);
+};
+
 }  // end namespace obrpc
 }  // end namespace oceanbase
 #endif
diff --git a/src/share/ob_srv_rpc_proxy.h b/src/share/ob_srv_rpc_proxy.h
index b27fb06945..05e4fa5eef 100644
--- a/src/share/ob_srv_rpc_proxy.h
+++ b/src/share/ob_srv_rpc_proxy.h
@@ -208,6 +208,8 @@ public:
   RPC_S(PR5 renew_in_zone_hb, OB_RENEW_IN_ZONE_HB, (share::ObInZoneHbRequest), share::ObInZoneHbResponse);
   RPC_AP(PR5 batch_get_protection_level, OB_BATCH_GET_PROTECTION_LEVEL, (ObBatchCheckLeaderArg), ObBatchCheckRes);
   RPC_S(PR5 kill_part_trans_ctx, OB_KILL_PART_TRANS_CTX, (obrpc::ObKillPartTransCtxArg));
+  RPC_S(PR5 fetch_sstable_size, obrpc::OB_FETCH_SSTABLE_SIZE, (obrpc::ObFetchSstableSizeArg),
+      obrpc::ObFetchSstableSizeRes);
 };  // end of class ObSrvRpcProxy
 
 }  // namespace obrpc
diff --git a/src/storage/ob_build_index_scheduler.cpp b/src/storage/ob_build_index_scheduler.cpp
index 0c0871222f..5951f7fe5f 100644
--- a/src/storage/ob_build_index_scheduler.cpp
+++ b/src/storage/ob_build_index_scheduler.cpp
@@ -1419,42 +1419,18 @@ int ObBuildIndexScheduleTask::schedule_dag()
 int ObBuildIndexScheduleTask::get_data_size(int64_t &data_size)
 {
   int ret = OB_SUCCESS;
-  ObSqlString sql;
-  SMART_VAR(ObMySQLProxy::MySQLResult, res)
-  {
-    sqlclient::ObMySQLResult *result = NULL;
-    char ip[common::OB_MAX_SERVER_ADDR_SIZE] = "";
-    if (OB_INVALID_ID == index_id_ || !pkey_.is_valid() || !candidate_replica_.is_valid()) {
-      ret = OB_INVALID_ARGUMENT;
-      LOG_WARN("invalid arguments", K(ret), K(index_id_), K(pkey_), K(candidate_replica_));
-    } else if (!candidate_replica_.ip_to_string(ip, sizeof(ip))) {
-      LOG_WARN("fail to convert ObAddr to ip", K(ret));
-    } else if (OB_FAIL(sql.assign_fmt(
-                   "SELECT used_size, MAX(major_version) from %s "
-                   "WHERE tenant_id = %ld AND table_id = %ld AND partition_id = %ld  AND sstable_id = %ld "
-                   "AND svr_ip = '%s' AND svr_port = %d",
-                   OB_ALL_VIRTUAL_STORAGE_STAT_TNAME,
-                   extract_tenant_id(index_id_),
-                   pkey_.get_table_id(),
-                   pkey_.get_partition_id(),
-                   index_id_,
-                   ip,
-                   candidate_replica_.get_port()))) {
-      STORAGE_LOG(WARN, "fail to assign sql", K(ret));
-    } else if (OB_FAIL(GCTX.sql_proxy_->read(res, sql.ptr()))) {
-      LOG_WARN("fail to execute sql", K(ret), K(sql));
-    } else if (OB_ISNULL(result = res.get_result())) {
-      ret = OB_ERR_UNEXPECTED;
-      STORAGE_LOG(WARN, "error unexpected, query result must not be NULL", K(ret));
-    } else if (OB_FAIL(result->next())) {
-      if (OB_LIKELY(OB_ITER_END == ret)) {
-        ret = OB_SUCCESS;
-      } else {
-        LOG_WARN("fail to get next row", K(ret));
-      }
-    } else {
-      EXTRACT_INT_FIELD_MYSQL(*result, "used_size", data_size, int64_t);
-    }
+  data_size = 0;
+  ObFetchSstableSizeArg arg;
+  ObFetchSstableSizeRes res;
+  arg.pkey_ = pkey_;
+  arg.index_id_ = index_id_;
+  if (OB_UNLIKELY(candidate_replica_.is_valid())) {
+    ret = OB_ERR_UNEXPECTED;
+    STORAGE_LOG(WARN, "candidate replica is invalid", K(ret), K(candidate_replica_));
+  } else if (OB_FAIL(GCTX.srv_rpc_proxy_->to(candidate_replica_).fetch_sstable_size(arg, res))) {
+    STORAGE_LOG(WARN, "fail to get sstable size", K(ret), K(arg));
+  } else {
+    data_size = res.size_;
   }
   return ret;
 }
diff --git a/src/storage/ob_build_index_task.cpp b/src/storage/ob_build_index_task.cpp
index bda16e300f..3f1a19a4d0 100644
--- a/src/storage/ob_build_index_task.cpp
+++ b/src/storage/ob_build_index_task.cpp
@@ -146,10 +146,11 @@ int ObBuildIndexDag::fill_comment(char* buf, const int64_t buf_len) const
     STORAGE_LOG(WARN, "ObBuildIndexDag has not been inited", K(ret));
   } else if (OB_FAIL(databuff_printf(buf,
                  buf_len,
-                 "build index task: key=%s index_id=%ld snapshot_version=%ld",
+                 "build index task: pkey=%s index_id=%ld snapshot_version=%ld parallelism=%ld",
                  to_cstring(pkey_),
                  index_id,
-                 param_.snapshot_version_))) {
+                 param_.snapshot_version_,
+                 param_.concurrent_cnt_))) {
     STORAGE_LOG(WARN, "failed to fill comment", K(ret), K(pkey_));
   }