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Vladimir Sitnikov commented on CALCITE-482: ------------------------------------------- [~danny0405], thanks for the feature, however it looks like RelOptRuleCall#transformTo needs adjustments. {noformat} public abstract void transformTo(RelNode rel, Map<RelNode, RelNode> equiv, BiFunction<RelNode, RelNode, RelNode> handler); {noformat} In practice, the hints are not applied to {{Map<RelNode, RelNode> equiv}} Was it intentional? Why is it like that? > Implement SQL and planner hints > ------------------------------- > > Key: CALCITE-482 > URL: https://issues.apache.org/jira/browse/CALCITE-482 > Project: Calcite > Issue Type: Improvement > Components: core > Affects Versions: 1.21.0 > Reporter: Vladimir Sitnikov > Assignee: Danny Chen > Priority: Major > Labels: pull-request-available > Fix For: 1.22.0 > > Time Spent: 8h 10m > Remaining Estimate: 0h > > Query optimizer can never be perfect, so it makes sense to implement hints to > allow user better control the execution. > For instance: "never merge this subquery with others" (`/+ no_merge/`), > "treat those tables as leading ones" (`/*+ leading */`), etc. > Hints would enable predictable performance and the planning time would be > improved as well. -- This message was sent by Atlassian Jira (v8.3.4#803005)