[jira] [Created] (DRILL-5897) Support Query Cancellation when WebConnection is closed on client side both for authenticated and unauthenticated user's

["Sorabh Hamirwasia (JIRA)" <ji...@apache.org>]

Sorabh Hamirwasia created DRILL-5897:
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             Summary: Support Query Cancellation when WebConnection is closed on client side both for authenticated and unauthenticated user's
                 Key: DRILL-5897
                 URL: https://issues.apache.org/jira/browse/DRILL-5897
             Project: Apache Drill
          Issue Type: Task
          Components: Web Server
            Reporter: Sorabh Hamirwasia


Today there is no session created (using cookies) for unauthenticated Webuser whereas for authenticated user's session is created. Also when a user submits a query then we wait until entire results is gathered on WebServer side and then send the entire Webpage in the response (probably that's how ftl works).
For authenticated user's we only cancel the queries in-flight when the session is invalidated (either by timeout or logout). However in absence of session we do nothing for unauthenticated user's so once a query is submitted it will run until it's failed or successful. The only way to explicitly cancel a query is from profile page which will not work when profiles are disabled.

We should research more on if it's possible to get the underlying WebConnection (not session) close event and cancel queries running as part of that connection close event. Also since today we will wait for entire query to finish on backend server and then send the response back, which is when a bad connection is detected it doesn't makes sense to cancel at that point (there is 1:1 mapping between request and connection) since query is already completed. Instead we can send header followed by batches of data (pagination) then we can detect early enough if connection is valid or not and cancel the query in response to that. More research is needed in this area along with knowledge of Jetty on how this can be achieved to make our WebServer more performant.



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