minkedong commented on issue #10519: URL: https://github.com/apache/druid/issues/10519#issuecomment-719326525
> For TopN, query engine collect top 1000(by default) ordered result from each segment, then merge all results to determine the global top 1000. For example, a data source has two segment A,B, for your second query, segment A, B contains value of (bundle, traffic) respectively (1115565187, 20) ranking 49 and (1115565187, 40) ranking 51, because of threshold = 50, query engine only collect result of segment A, result of B drop, which is approximate. But for your first query with filter, segment A, B contains value of (bundle, traffic) respectively (1115565187, 20) ranking 1 and (1115565187, 40) ranking 1 , result collected is accurate. if you need accurate result of your second query, try to increase threshold. @zoov-w Thank you very much for your answer, Your answer helped me solve the problem and at the same time let me understand the cause of the problem, great! ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
