org.apache.hadoop.hive.ql.optimizer.calcite.rules.HiveUnionMergeRule Maven / Gradle / Ivy
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* to you under the Apache License, Version 2.0 (the
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* http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.hadoop.hive.ql.optimizer.calcite.rules;
import java.util.ArrayList;
import java.util.List;
import org.apache.calcite.plan.RelOptRule;
import org.apache.calcite.plan.RelOptRuleCall;
import org.apache.calcite.rel.RelNode;
import org.apache.hadoop.hive.ql.optimizer.calcite.reloperators.HiveIntersect;
import org.apache.hadoop.hive.ql.optimizer.calcite.reloperators.HiveUnion;
import org.apache.calcite.util.Util;
/**
* Planner rule that merges multiple union into one
* Before the rule, it is
* union all-branch1
* |-----union all-branch2
* |-----branch3
* After the rule, it becomes
* union all-branch1
* |-----branch2
* |-----branch3
* {@link org.apache.hadoop.hive.ql.optimizer.calcite.reloperators.HiveUnion}
*/
public class HiveUnionMergeRule extends RelOptRule {
public static final HiveUnionMergeRule INSTANCE = new HiveUnionMergeRule();
// ~ Constructors -----------------------------------------------------------
private HiveUnionMergeRule() {
super(
operand(HiveUnion.class, operand(RelNode.class, any()), operand(RelNode.class, any())));
}
// ~ Methods ----------------------------------------------------------------
public void onMatch(RelOptRuleCall call) {
final HiveUnion topUnion = call.rel(0);
final HiveUnion bottomUnion;
if (call.rel(2) instanceof HiveUnion) {
bottomUnion = call.rel(2);
} else if (call.rel(1) instanceof HiveUnion) {
bottomUnion = call.rel(1);
} else {
return;
}
List inputs = new ArrayList<>();
if (call.rel(2) instanceof HiveUnion) {
for (int i = 0; i < topUnion.getInputs().size(); i++) {
if (i != 1) {
inputs.add(topUnion.getInput(i));
}
}
inputs.addAll(bottomUnion.getInputs());
} else {
inputs.addAll(bottomUnion.getInputs());
inputs.addAll(Util.skip(topUnion.getInputs()));
}
HiveUnion newUnion = (HiveUnion) topUnion.copy(
topUnion.getTraitSet(), inputs, true);
call.transformTo(newUnion);
}
}