[ https://issues.apache.org/jira/browse/CALCITE-4302?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
ASF GitHub Bot updated CALCITE-4302: ------------------------------------ Labels: pull-request-available (was: ) > Improve cost propagation in volcano to avoid re-propagation > ----------------------------------------------------------- > > Key: CALCITE-4302 > URL: https://issues.apache.org/jira/browse/CALCITE-4302 > Project: Calcite > Issue Type: Improvement > Reporter: Botong Huang > Priority: Major > Labels: pull-request-available > Time Spent: 10m > Remaining Estimate: 0h > > CALCITE-3330 changed the cost propagation in volcano from DFS to BFS. > However, there is still room for improvement. A subset can be updated more > than once in a cost propagation process. For instance, A -> D, A -> B -> C -> > D. When subset A has an update, using BFS subset D (and thus all subsets > above/after D) can be updated twice, first via A -> D and then C -> D. We can > further improve the BFS by always popping the relNode with the smallest cost > from the queue, similar to the Dijkstra algorithm. So that whenever a relNode > is popped from the queue, its current best cannot be further deceased any > more. As a result, all subsets will only be propagated at most once. -- This message was sent by Atlassian Jira (v8.3.4#803005)