Zookeeper watch reference table

Watcher settings are the most common in development. You need to understand some basic features of watcher. Different watcher information is received for different operations on nodes of exists, getdata, and getchild. The change of the parent node and the sun node will not trigger watcher, but the change of the watcher node and the child node will trigger watcher. For details, refer to the table below.

Operation	Method	Trigger watcher	Watcher state	Watcher type	Watcher path
Create current node	Getdata	×	×	×	×
	Getchildren	√	3	4	√
	Exists	×	×	×	×
Set current node	Getdata	√	3	3	√
	Getchildren	×	×	×	×
	Exists	√	3	3	√
Delete current node	Getdata	√	3	2	√
	Getchildren	√	3	2	√
	Exists	√	3	2	√
Create subnode	Getdata	×	×	×	×
	Getchildren	√	3	4	√
	Exists	×	×	×	×
Set subnode	Getdata	×	×	×	×
	Getchildren	×	×	×	×
	Exists	×	×	×	×
Delete subnode	Getdata	×	×	×	×
	Getchildren	√	3	4	√
	Exists	×	×	×	×
Restore connection	Getdata	√	1	-1	×
	Getchildren	√	1	-1	×
	Exists	√	1	-1	×
Session restoration has not timed out.	Getdata	√	-112	-1	×
	Getchildren	√	-112	-1	×
	Exists	√	-112	-1	×
Session restoration timeout	Getdata	√	3	-1	×
	Getchildren	√	3	-1	×
	Exists	√	3	-1	×

Note: State = 2 indicates the deletion event; State = 3 indicates the node data change; State = 4 indicates the subnode event; State =-1 indicates the session event. Type =-112 indicates that the session is invalid; type = 1 indicates that the session is being established; tpye = 3 indicates that the session is successfully established. * Indicates no, and √ indicates yes.

Zookeeper watch reference table