TiDB 突然访问不了,需要重启TiKV和TiDB才恢复

升级前:
select tidb_version() :

  • Version: 2.1.0-alpha.1-ff3dd160846b7d1aed9079c389fc188f7f5ea13e
    Check Table Before Drop: false’’’
  • Release Version: v3.0.0
  • Git Commit Hash: 60965b006877ca7234adaced7890d7b029ed1306
  • Git Branch: HEAD
  • UTC Build Time: 2019-06-28 12:14:07
  • GoVersion: go version go1.12 linux/amd64
  • Race Enabled: false
  • TiKV Min Version: 2.1.0-alpha.1-ff3dd160846b7d1aed9079c389fc188f7f5ea13e
  • Check Table Before Drop: false

升级后:
v3.1.1

连接数不多,只有十几个

和这个单情况有点像,但不知道是怎么解决的?