[ https://issues.apache.org/jira/browse/CALCITE-3920?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
ASF GitHub Bot updated CALCITE-3920: ------------------------------------ Labels: pull-request-available pull-requests-available (was: pull-requests-available) > Improve ORDER BY computation in Enumerable convention by exploiting LIMIT > ------------------------------------------------------------------------- > > Key: CALCITE-3920 > URL: https://issues.apache.org/jira/browse/CALCITE-3920 > Project: Calcite > Issue Type: Improvement > Components: core > Affects Versions: 1.22.0 > Reporter: Stamatis Zampetakis > Assignee: Thomas Rebele > Priority: Major > Labels: pull-request-available, pull-requests-available > Time Spent: 20m > Remaining Estimate: 0h > > There are many use-cases (pagination, top-k) relying on queries with an ORDER > BY clause followed by a LIMIT. > At the moment, the two operations are implemented independently the one from > the other > in the Enumerable convention. Even when we know that consumer needs only the > top-10 results the sort operation will try to maintain its entire input > sorted. The complexity of the sorting operation is O( n ) space and O( nlogn > ) time, where n is the size of the input. > By implementing ORDER BY and LIMIT together there are various optimizations > that can be applied to reduce the space and time complexity of the sorting > algorithm. -- This message was sent by Atlassian Jira (v8.3.4#803005)