This topic describes how to create and update the RootService list. Updates may occur automatically, manually, or based on specific triggering a condition.
What is the RootService list?
The RootService (RS) list contains the IP addresses of servers that run the RootService in the OceanBase Database cluster. Typically, each zone has a server that runs the RootService. Two types of RS lists are available:
RS lists that are directly obtained from the configuration server. This set of RS lists is called RS list [ null] .
RS lists that are refreshed after the servers are updated. This set of RS lists is called RS list [list of servers] .
Create an RS list
When ODP accesses a cluster for the first time, it sends an HTTP request to obtain the latest RS list of the cluster from the configuration server. This RS list belongs to the RS list [null] set.
Automatically update an RS list
After a cluster is created, ODP schedules a task for the cluster.
At a customizable interval (20s by default), ODP accesses the
all_virtual_proxy_server_stattable to obtain the list of servers. If the server list is changed, the RS list is updated as well. This RS list belongs to the RS list [ list of servers ] set.If the scheduled task fails to refresh the list for more than 10 times, ODP obtains the latest RS list from the configuration server. The RS list once again belongs to the RS list [null] set.
The condition that triggers the update of an RS list
If you have not accessed the cluster for a long time (more than 24 hours by default), and you have failed for more than 3 times when you re-create the cluster, ODP obtains a new RS list from the configuration server the next time you create the cluster. This RS list belongs to the RS list [null] set.
Manually update an RS list
You can change the value of the refresh_rslist parameter to true. ODP then refreshes all RS lists. The refreshed RS lists belong to the RS list [null] set.