Global settings

[zhang2014]

SET GLOBAL max_block_size = 30;
-- We should store the settings in meta service and get this for cluster other nodes of the tenant.

Tasks:

• Refine the session: change mutable status to session context
• Add settings set in meta
• Write/Read global settings for settings
• SET GLOBAL xx=yy statement

[BohuTANG]

From the experience of snow, it seems that the settings should bind with tenant not the cluster, from the user side, he shouldn't know what's the cluster is.
So, what is the purpose related to the cluster setting here?

[zhang2014]

From the experience of snow, it seems that the settings should bind with tenant not the cluster, from the user side, he shouldn't know what's the cluster is.
So, what is the purpose related to the cluster setting here?

This can be useful when opening the features of different warehouses. For example, on user side, the test cluster (read-only) and the stable cluster may share the same data, but they have different settings. But it seems that global is more suitable for tenants.

Possible solutions(multiple level settings):

SET GLOBAL enable_some_experimental_feature = false; -- tenant
SET WAREHOUSE enable_some_experimental_feature = true; -- cluster(higher priority)

I misunderstood. you are right. in this case, we may use the shared data feature(different tenant). SET GLOBAL should bind with tenant level.

[BohuTANG]

I think we can restart the task now.
cc @zhang2014 @sundy-li