/*
* 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.pig.backend.hadoop.executionengine.tez.plan.optimizer;
import java.util.List;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.pig.backend.hadoop.executionengine.physicalLayer.PhysicalOperator;
import org.apache.pig.backend.hadoop.executionengine.physicalLayer.expressionOperators.ConstantExpression;
import org.apache.pig.backend.hadoop.executionengine.physicalLayer.plans.PhysicalPlan;
import org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators.POFilter;
import org.apache.pig.backend.hadoop.executionengine.physicalLayer.util.PlanHelper;
import org.apache.pig.backend.hadoop.executionengine.tez.plan.TezOpPlanVisitor;
import org.apache.pig.backend.hadoop.executionengine.tez.plan.TezOperPlan;
import org.apache.pig.backend.hadoop.executionengine.tez.plan.TezOperator;
import org.apache.pig.impl.plan.DependencyOrderWalker;
import org.apache.pig.impl.plan.PlanException;
import org.apache.pig.impl.plan.VisitorException;
/**
* For historical reasons splits will always produce filters that pass
* everything through unchanged. This optimizer removes these.
*
* The condition we look for is POFilters with a constant boolean
* (true) expression as it's plan.
*/
public class NoopFilterRemover extends TezOpPlanVisitor {
private static Log LOG = LogFactory.getLog(NoopFilterRemover.class);
public NoopFilterRemover(TezOperPlan plan) {
super(plan, new DependencyOrderWalker<TezOperator, TezOperPlan>(plan));
}
@Override
public void visitTezOp(TezOperator tezOp) throws VisitorException {
if (tezOp.getSplitParent() == null) {
return;
}
try {
List<POFilter> filters = PlanHelper.getPhysicalOperators(tezOp.plan, POFilter.class);
for (POFilter filter : filters) {
PhysicalPlan filterPlan = filter.getPlan();
if (filterPlan.size() == 1) {
PhysicalOperator fp = filterPlan.getRoots().get(0);
if (fp instanceof ConstantExpression) {
ConstantExpression exp = (ConstantExpression)fp;
Object value = exp.getValue();
if (value instanceof Boolean) {
Boolean filterValue = (Boolean)value;
if (filterValue) {
tezOp.plan.removeAndReconnect(filter);
}
}
}
}
}
} catch (PlanException e) {
throw new VisitorException(e);
}
}
}