text: create schema if not exists dtm_barrier;
  drop table if exists dtm_barrier.barrier;
  CREATE SEQUENCE if not EXISTS dtm_barrier.barrier_seq;
  create table if not exists dtm_barrier.barrier(
    id bigint NOT NULL DEFAULT NEXTVAL ('dtm_barrier.barrier_seq'),
    trans_type varchar(45) default '',
    gid varchar(128) default '',
    branch_id varchar(128) default '',
    op varchar(45) default '',
    barrier_id varchar(45) default '',
    reason varchar(45) default '',
    create_time timestamp(0) DEFAULT NULL,
    update_time timestamp(0) DEFAULT NULL,
    PRIMARY KEY(id),
    CONSTRAINT uniq_barrier unique(gid, branch_id, op, barrier_id)
  );