[ https://issues.apache.org/jira/browse/IMPALA-10025?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Tim Armstrong resolved IMPALA-10025. ------------------------------------ Resolution: Invalid I'm going to do this in the first version of the patch > Avoid rebuilding in-memory heap during output phase of top-n > ------------------------------------------------------------ > > Key: IMPALA-10025 > URL: https://issues.apache.org/jira/browse/IMPALA-10025 > Project: IMPALA > Issue Type: Sub-task > Components: Backend > Reporter: Tim Armstrong > Assignee: Tim Armstrong > Priority: Major > > In the patch for IMPALA-9853, we reuse some code in the output phase that > necessitated building the in-memory heap from the sorter's output. This has > some inherent overhead that gets worse for larger limits and/or partition > counts. > It would be better to have the sorter do a full sort on partition/order by > columns and then apply the limit while streaming the results back from the > sorter. In combination with IMPALA-10023 this would let us gracefully degrade > to doing something closer to a regular sort and probably let us bump > ANALYTIC_PUSHDOWN_THRESHOLD. -- This message was sent by Atlassian Jira (v8.3.4#803005) --------------------------------------------------------------------- To unsubscribe, e-mail: issues-all-unsubscr...@impala.apache.org For additional commands, e-mail: issues-all-h...@impala.apache.org