我想了解更多关于复制品（即。 system.replicas.is_leader )在clickhouse数据库中。
文件说明如下：

is_leader:          Whether the replica is the leader.
Only one replica can be the leader at a time. The leader is responsible for selecting background merges to perform.
Note that writes can be performed to any replica that is available and has a session in ZK, regardless of whether it is a leader.

这在我看来很模糊。有没有人知道关于领导者复制品的更多细节？
领导者复制品有什么需要注意的吗？
我可以读/写一个领导者的副本，像一个标准的？
领导人选举如何运作？
领导层什么时候换？