[IMPALA-7031] Add additional info to query canceled from http endpoint

• Type: New Feature
• Status: Closed
• Priority: Major
• Resolution: Won't Do
• Affects Version/s: Impala 3.0
• Component/s: Distributed Exec
• Labels: query-lifecycle
• Target Version: Product Backlog
• Epic Color: ghx-label-7
• Assignee: Alice Fan
• Reporter: Adriano
• Created: 15/May/18 11:24
• Updated: 21/Jan/20 03:32
• Resolved: 21/Jan/20 03:32

Description

In big clusters with many jdbc/odbc users, in order to save resources are often implemented scripts that automatically cancel queries (e.g. long running queries) (the scripts typically are using the Impala Webui).

Typical Scenario:

1. A jdbc/odbc client submit a query
2. The Coordinator start the query execution
3. The query is cancelled from the Coordinator WebUi
4. The jdbc/odbc client ask to the Coordinator the query status (GetOperationStatus)
5. The Coordinator answer "unknown query ID" (as the query was cancelled)
6. For the client perspective the query failed for "unknown query ID"

Currently, if a running query is cancelled from the impalad WebUI, the client will just receive an 'unknown query ID' error on the next fetch/getOperationStatus attempt. It would be good to be able to explicitly call out this case.