Affects Version/s: None
Fix Version/s: None
Change error & cancel logic on query execution.
- propagated from source to downstream nodes.
- Always propagated to the RootNode;
- RootNode receive an error and cancel all execution tree.
- propagated from downstream to source;
- any node may cancel its execution sub-tree;
- (technical details) to prevent race on Inbox creation Outbox resend Cancel message to Inbox.