为提高效率，提问时请提供以下信息，问题描述清晰可优先响应。
- 【TiDB 版本】：V3.0.12
- 【问题描述】：使用operator add split-region 处理热点regions 问题，可是反问更严重了，什么问题呀？
发现 split-region 只是把一个region 变成了两个，并且还在这个store上面，没有迁移的动作，热点问题还是不能解决。
下面为拆分之前的状况：
root@EM-6CU649E6X8: ~# python table-regions.py --host ip --port 10080 dbname asset_his
[RECORD - dbname.asset_his] - Leaders Distribution:
total leader count: 7
store: 17, num_leaders: 1, percentage: 14.29%
store: 11, num_leaders: 1, percentage: 14.29%
store: 12, num_leaders: 1, percentage: 14.29%
store: 14, num_leaders: 1, percentage: 14.29%
**store: 15, num_leaders: 3, percentage: 42.86%**
执行15 store 对应的regions 进行拆分：
./pd-ctl -u http://ip:2379 operator add split-region 170659
./pd-ctl -u http://ip:2379 operator add split-region 170602
./pd-ctl -u http://ip:2379 operator add split-region 170701
./pd-ctl -u http://ip:2379 operator add split-region 170667
之后在查看：
[RECORD - dbname.asset_his] - Leaders Distribution:
total leader count: 9
store: 17, num_leaders: 1, percentage: 11.11%
store: 11, num_leaders: 1, percentage: 11.11%
store: 12, num_leaders: 1, percentage: 11.11%
store: 14, num_leaders: 1, percentage: 11.11%
**store: 15, num_leaders: 5, percentage: 55.56%**
还是分在了该15号store 上面了
再执行一次operator add split-region
发现还是在改store 上进行拆分，并没有迁移到其他store上面
total leader count: 13
store: 17, num_leaders: 1, percentage: 7.69%
store: 11, num_leaders: 1, percentage: 7.69%
store: 12, num_leaders: 1, percentage: 7.69%
store: 14, num_leaders: 1, percentage: 7.69%
store: 15, num_leaders: 9, percentage: 69.23%
下面为面板信息：
若提问为性能优化、故障排查类问题，请下载脚本运行。终端输出打印结果，请务必全选并复制粘贴上传。
