[BUG] change error to warning

src/storage/memtable/ob_concurrent_control.cpp

@@ -161,7 +161,7 @@ int check_sequence_set_violation(const concurrent_control::ObWriteFlag write_fla
       // may break the promise of the memtable semantics. We need to be aware of
       // this situation and retry the entire SQL statement in such cases.
       ret = OB_SEQ_NO_REORDER_UNDER_PDML;
-      TRANS_LOG(ERROR, "wrong row of sequence on one row found", K(reader_seq_no),
+      TRANS_LOG(WARN, "wrong row of sequence on one row found", K(reader_seq_no),
                 K(writer_tx_id), K(writer_dml_flag), K(writer_seq_no),
                 K(locker_tx_id), K(locker_dml_flag), K(locker_seq_no));
     }