- 【TiDB 版本】：v3.0.12
- 【问题描述】：
region score突然变得很不稳定，这个score是怎么计算得到的？
{
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“address”: “172.18.69.174:20160”,
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“status”: {
“capacity”: “6.93TiB”,
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“leader_count”: 25863,
“leader_weight”: 1,
“leader_score”: 5340750,
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“region_count”: 79590,
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“region_score”: 16703192,
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“start_ts”: “2020-12-09T21:49:55+08:00”,
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“region_count”: 79246,
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“region_score”: 16702847,
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“sending_snap_count”: 1,
“start_ts”: “2020-12-09T21:34:20+08:00”,
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“leader_count”: 25732,
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“region_size”: 16702867,
“start_ts”: “2020-12-09T20:51:48+08:00”,
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pd 计算 region score 是一个分段函数计算的，当剩余空间容量低于某一个值的时候，对应的分段函数斜率会比较大。
有两个对应的 pd 参数控制，high-space-ratio 已经 low-space-ratio
当 TiKV 实例空间使用率达到 high-space-ratio 的时候，会计算 region score 比较高，这样可以让 region 尽量调度到别的节点上，平衡各个实例之间的空间使用率。
可以通过 pd-ctl 执行 config show all 确认 high-space-ratio 和 low-space-ratio 设置值，并根据实际情况可以进行调整。
