morrySnow commented on code in PR #36567:
URL: https://github.com/apache/doris/pull/36567#discussion_r1651016828
##########
fe/fe-core/src/main/java/org/apache/doris/nereids/rules/exploration/mv/AbstractMaterializedViewAggregateRule.java:
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@@ -331,11 +337,64 @@ private boolean isGroupByEquals(Pair<Plan,
LogicalAggregate<Plan>> queryTopPlanA
queryAggregate.getGroupByExpressions(), queryTopPlan,
queryStructInfo.getTableBitSet())) {
queryGroupShuttledExpression.add(queryExpression);
}
+
+ // try to eliminate group by dimension by function dependency if group
by expression is not in query
+ Map<Expression, Expression>
viewShuttledExpressionQueryBasedToGroupByExpressionMap = new HashMap<>();
+ Map<Expression, Expression>
groupByExpressionToViewShuttledExpressionQueryBasedMap = new HashMap<>();
+ List<Expression> viewGroupByExpressions =
viewAggregate.getGroupByExpressions();
+ List<? extends Expression> viewGroupByShuttledExpressions =
ExpressionUtils.shuttleExpressionWithLineage(
+ viewGroupByExpressions, viewTopPlan,
viewStructInfo.getTableBitSet());
+
+ for (int index = 0; index < viewGroupByExpressions.size(); index++) {
+ Expression viewExpression = viewGroupByExpressions.get(index);
+ Expression viewGroupExpressionQueryBased = ExpressionUtils.replace(
+ viewGroupByShuttledExpressions.get(index),
+ viewToQuerySlotMapping.toSlotReferenceMap());
+
viewShuttledExpressionQueryBasedToGroupByExpressionMap.put(viewGroupExpressionQueryBased,
+ viewExpression);
+
groupByExpressionToViewShuttledExpressionQueryBasedMap.put(viewExpression,
+ viewGroupExpressionQueryBased
+ );
+ }
+ if
(queryGroupShuttledExpression.equals(viewShuttledExpressionQueryBasedToGroupByExpressionMap.values()))
{
+ // return true, if equals directly
+ return true;
+ }
+ List<NamedExpression> projects = new ArrayList<>();
+ for (Expression expression : queryGroupShuttledExpression) {
+ if
(!viewShuttledExpressionQueryBasedToGroupByExpressionMap.containsKey(expression))
{
+ // query group expression is not in view group by expression
+ return false;
+ }
+ Expression chosenExpression =
viewShuttledExpressionQueryBasedToGroupByExpressionMap.get(expression);
+ projects.add(chosenExpression instanceof NamedExpression
+ ? (NamedExpression) chosenExpression : new
Alias(chosenExpression));
+ }
+ LogicalProject<LogicalAggregate<Plan>> project = new
LogicalProject<>(projects, viewAggregate);
+ // try to eliminate group by expression which is not in query group by
expression
+ Plan rewrittenPlan =
MaterializedViewUtils.rewriteByRules(cascadesContext,
+ childContext -> {
+ Rewriter.getCteChildrenRewriter(childContext,
+ ImmutableList.of(Rewriter.topDown(new
EliminateGroupByKey()))).execute();
Review Comment:
why need apply this rule seperately? rewrite the whole mv plan tree could
not eliminate group by key?
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