根据我的经验，ZK 超时几乎总是由于 Solr 节点上的某些原因，而不是 ZK 中的问题.

In my experience, ZK timeouts have almost always been due to something on the Solr node, rather than a problem in ZK.

您没有提供所有时间戳，但理论上是这样的:

You don't provide all the timestamps, but the theory is that:

1. Solr 由于某种原因未能发送心跳
2. ZK 假设客户端已经离开并关闭连接
3. Solr 尝试使用 ZK 关闭的连接

那么为什么 Solr 节点可能无法发送心跳?这可能是因为 Solr 节点只是过载了(线程尖峰是原因还是症状?)或者只是通过很长的 GC 暂停也可以做到这一点.

So why might the Solr node fail to send the heartbeat? This could be because the Solr node was simply overloaded, (Is the thread spike a cause, or a symptom?) or just working through a very long GC pause could do it too.