学步园

begin
  --迁移数据
  insert into tb_users
    select  *
      from tb_users_dbc a
     where gmt_modified <= trunc(sysdate) - v_day and rownum<5000000;
   --删除原表数据   
  delete from tb_users_dbc
     where gmt_modified <= trunc(sysdate) - v_day and rownum<5000000;
 commit;
end;

declare
  v_counts number := 0;
begin
 --中间表
  insert into tmp_tb_users
    select *
      from tb_users_dbc
     where gmt_modified <= trunc(sysdate) - v_day and rownum<5000000;
    commit;
  for i in (select id from tmp_tb_users) loop
    --数据迁移
    insert into tb_users
      select * from tb_users_dbc where id = i.id;
    delete from tb_users_dbc where id = i.id;
    v_counts := v_counts + 1;
    --分批提交
    if mod(v_counts, 100) = 0 then
      commit;
    end if;
  end loop;
end;

declare
  type rec_rids is table of varchar2(32);
  v_rids rec_rids;
  cursor cur_aids is
    select id
      from tb_users_dbc
     where gmt_modified <= trunc(sysdate) - v_day and rownum<5000000;
begin
  open cur_aids;
  loop
    fetch cur_aids BULK COLLECT INTO v_rids LIMIT 1000;
    for i in 1 .. v_rids.count loop
      --数据迁移
      insert into tb_users
        select * from tb_users_dbc where id = v_rids(i);
      delete from tb_users_dbc where id = v_rids(i);
    end loop;
    commit;
    EXIT WHEN v_rids.COUNT = 0;
    end loop;
    close cur_aids;
end;

declare
  pagecount number;
  sumcount  number;
  loopcount number;
begin
  --取要迁移的数据
  execute immediate 'truncate table tmp_tb_users';
  insert into tmp_tb_users
    select id
      from tb_users_dbc
     where gmt_modified <= trunc(sysdate) - v_day and rownum < 5000000;
  --计算迁移总数
  select count(*) into sumcount from tmp_tb_users;
  --设定每次迁移条数
  pagecount = 2000;
  --得到循环次数
  loopcount := sumcount / pagecount + 1;
  for i in 1 .. loopcount loop
    begcount := (i - 1) * pagecount + 1;
    endcount := i * pagecount;
    --构建中间小表
    execute immediate 'truncate table mid_tb_users';
    insert into mid_tb_users
      select id, b.rn
        from tmp_tb_users b where b.rn >= begcount and b.rn <= endcount;
    --小表和原表进行关联，迁移数据
    insert into tb_users
      select f.*
        from mid_tb_users t, tb_users_dbc f
       where t.biz_order_id = f.biz_order_id
         and t.rn >= begcount  and t.rn < = endcount;
    --删除原表数据
    delete from tb_users_dbc where id in (select id from mid_tb_users);
    commit;
  end loop;
end;