hsyuan commented on a change in pull request #1160: [CALCITE-2712] Add rule to
eliminate unnecessary outer join
URL: https://github.com/apache/calcite/pull/1160#discussion_r276744020
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File path: core/src/main/java/org/apache/calcite/plan/RelOptUtil.java
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@@ -735,6 +737,95 @@ public static RelNode createCastRel(
}
}
+ /** Transforms the aggregate call according to the limit and offset. */
+ public static List<AggregateCall> transformAggregateCall(
+ List<AggregateCall> aggregateCalls, int limit, int offset) {
+ // Adjust arguments of the aggregate call.
+ final List<AggregateCall> newAggregateCall = new ArrayList<>();
+ for (AggregateCall aggregateCall : aggregateCalls) {
+ final List<Integer> args = new ArrayList<>();
+ aggregateCall.getArgList()
+ .forEach(i -> args.add(i >= limit ? i - offset : i));
+
+ newAggregateCall.add(AggregateCall
+ .create(aggregateCall.getAggregation(), aggregateCall.isDistinct(),
+ aggregateCall.isApproximate(), aggregateCall.ignoreNulls(), args,
+ aggregateCall.filterArg, aggregateCall.getCollation(),
+ aggregateCall.getType(), aggregateCall.getName()));
+ }
+ return newAggregateCall;
+ }
+
+ /** Transforms the condition according to the limit and offset. */
+ public static RexNode transformCondition(RexNode condition,
+ RexBuilder rexBuilder, int limit, int offset) {
+ RexShuttle shuttle = new RexShuttle() {
+ @Override public RexNode visitInputRef(RexInputRef inputRef) {
+ int index = inputRef.getIndex();
+ if (index >= limit) {
+ return rexBuilder.makeInputRef(inputRef.getType(), index - offset);
+ }
+ return inputRef;
+ }
+ };
+ return condition.accept(shuttle);
+ }
+
+ /**
+ * Whether it can remove join according to the aggregate.
+ *
+ * @param aggregate Aggregate
+ * @param lowerLimit lower limit (included)
+ * @param upperLimit upper limit (excluded)
Review comment:
The explanation of lower/upper limit is unclear.
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