/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.hadoop.hive.ql.optimizer.calcite.reloperators;
import org.apache.calcite.plan.RelOptCluster;
import org.apache.calcite.plan.RelTraitSet;
import org.apache.calcite.rel.RelNode;
import org.apache.calcite.rel.RelShuttle;
import org.apache.calcite.rel.core.Filter;
import org.apache.calcite.rex.RexCall;
import org.apache.calcite.rex.RexCorrelVariable;
import org.apache.calcite.rex.RexFieldAccess;
import org.apache.calcite.rex.RexSubQuery;
import org.apache.calcite.rex.RexNode;
import org.apache.hadoop.hive.ql.optimizer.calcite.HiveRelShuttle;
import org.apache.hadoop.hive.ql.optimizer.calcite.TraitsUtil;
import org.apache.calcite.rel.core.CorrelationId;
import java.util.Set;
import java.util.HashSet;
public class HiveFilter extends Filter implements HiveRelNode {
public HiveFilter(RelOptCluster cluster, RelTraitSet traits, RelNode child, RexNode condition) {
super(cluster, TraitsUtil.getDefaultTraitSet(cluster), child, condition);
}
@Override
public Filter copy(RelTraitSet traitSet, RelNode input, RexNode condition) {
assert traitSet.containsIfApplicable(HiveRelNode.CONVENTION);
return new HiveFilter(getCluster(), traitSet, input, condition);
}
@Override
public void implement(Implementor implementor) {
}
private static void findCorrelatedVar(RexNode node, Set<CorrelationId> allVars) {
if(node instanceof RexCall) {
RexCall nd = (RexCall)node;
for (RexNode rn : nd.getOperands()) {
if (rn instanceof RexFieldAccess) {
final RexNode ref = ((RexFieldAccess) rn).getReferenceExpr();
if (ref instanceof RexCorrelVariable) {
allVars.add(((RexCorrelVariable) ref).id);
}
} else {
findCorrelatedVar(rn, allVars);
}
}
}
}
//traverse the given node to find all correlated variables
// Note that correlated variables are supported in Filter only i.e. Where & Having
private static void traverseFilter(RexNode node, Set<CorrelationId> allVars) {
if(node instanceof RexSubQuery) {
//we expect correlated variables in HiveFilter only for now.
// Also check for case where operator has 0 inputs .e.g TableScan
RelNode input = ((RexSubQuery)node).rel.getInput(0);
while(input != null && !(input instanceof HiveFilter)
&& input.getInputs().size() >=1) {
//we don't expect corr vars withing JOIN or UNION for now
// we only expect cor vars in top level filter
if(input.getInputs().size() > 1) {
return;
}
input = input.getInput(0);
}
if(input != null && input instanceof HiveFilter) {
findCorrelatedVar(((HiveFilter)input).getCondition(), allVars);
}
return;
}
//AND, NOT etc
if(node instanceof RexCall) {
int numOperands = ((RexCall)node).getOperands().size();
for(int i=0; i<numOperands; i++) {
RexNode op = ((RexCall)node).getOperands().get(i);
traverseFilter(op, allVars);
}
}
}
@Override
public Set<CorrelationId> getVariablesSet() {
Set<CorrelationId> allCorrVars = new HashSet<>();
traverseFilter(condition, allCorrVars);
return allCorrVars;
}
public static Set<CorrelationId> getVariablesSet(RexSubQuery e) {
Set<CorrelationId> allCorrVars = new HashSet<>();
traverseFilter(e, allCorrVars);
return allCorrVars;
}
public RelNode accept(RelShuttle shuttle) {
if (shuttle instanceof HiveRelShuttle) {
return ((HiveRelShuttle)shuttle).visit(this);
}
return shuttle.visit(this);
}
}