This way, any node in the cluster knows which nodes have which system views.
From the query engine perspective the system view is an unmodifiable table that is located in SYSTEM
schema. System views don't support transactions. With each query, the sql engine requests data from the system view data provider, which does not have transaction integration. That is, regardless of whether a transaction has started or not, each query to the system view may return a different set of data.
Cluster-wide view data can be obtained on any node so the view of this type has a single distribution.
Local node view data must be obtained on every node where view is registered, so it uses special identity-distribution, that calculates destinations based on a value of the row field.