oleg-zinovev commented on code in PR #12096:
URL: https://github.com/apache/ignite/pull/12096#discussion_r2253911086
##########
modules/calcite/src/main/java/org/apache/ignite/internal/processors/query/calcite/prepare/PlannerPhase.java:
##########
@@ -98,6 +101,22 @@ public enum PlannerPhase {
}
},
+ /** */
+ HEP_WINDOW_SPLIT("Heuristic phase to split project to project and window")
{
+ @Override public RuleSet getRules(PlanningContext ctx) {
+ return ctx.rules(
+ RuleSets.ofList(
+ CoreRules.PROJECT_TO_LOGICAL_PROJECT_AND_WINDOW,
Review Comment:
@alex-plekhanov
**Problem**
Calcite’s FILTER_PROJECT_TRANSPOSE rule does not transpose filters when the
projection contains an OVER clause (i.e., a window function).
This behavior is explicitly enforced in FilterProjectTransposeRule.java.
At the same time, window-specific rules like FILTER_WINDOW_TRANSPOSE and
PROJECT_WINDOW_TRANSPOSE only apply after window expressions have been
converted into logical Window nodes.
**Observation**
This creates a limitation:
During the HEP_FILTER_PUSH_DOWN and HEP_PROJECT_PUSH_DOWN phases, filters
and projections cannot be pushed down if OVER expressions are still embedded in
projections.
Conclusion
To ensure proper operation of HEP_FILTER_PUSH_DOWN and
HEP_PROJECT_PUSH_DOWN, all OVER expressions must be already transformed into
logical Window relations beforehand.
**Suggested Actions**
- Add PROJECT_TO_LOGICAL_PROJECT_AND_WINDOW in HEP_FILTER_PUSH_DOWN pahse so
that the transformation of OVER into LogicalWindow occurs before other filter
push down rules.
- Alternatively, introduce an intermediate phase to extract OVER expressions
earlier in the pipeline (HEP_WINDOW_SPLIT phase in pull request)
Let me know if you'd like to propose a more robust solution.
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