/*
* 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.newplan.logical.rules;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.apache.pig.FuncSpec;
import org.apache.pig.data.DataType;
import org.apache.pig.impl.builtin.IdentityColumn;
import org.apache.pig.impl.logicalLayer.FrontendException;
import org.apache.pig.impl.util.Pair;
import org.apache.pig.newplan.Operator;
import org.apache.pig.newplan.OperatorPlan;
import org.apache.pig.newplan.OperatorSubPlan;
import org.apache.pig.newplan.logical.expression.LogicalExpression;
import org.apache.pig.newplan.logical.expression.LogicalExpressionPlan;
import org.apache.pig.newplan.logical.expression.ProjectExpression;
import org.apache.pig.newplan.logical.expression.UserFuncExpression;
import org.apache.pig.newplan.logical.optimizer.SchemaResetter;
import org.apache.pig.newplan.logical.optimizer.UidResetter;
import org.apache.pig.newplan.logical.relational.LOCross;
import org.apache.pig.newplan.logical.relational.LOForEach;
import org.apache.pig.newplan.logical.relational.LOGenerate;
import org.apache.pig.newplan.logical.relational.LOInnerLoad;
import org.apache.pig.newplan.logical.relational.LOJoin;
import org.apache.pig.newplan.logical.relational.LOSort;
import org.apache.pig.newplan.logical.relational.LogicalPlan;
import org.apache.pig.newplan.logical.relational.LogicalRelationalOperator;
import org.apache.pig.newplan.logical.relational.LogicalSchema;
import org.apache.pig.newplan.logical.relational.LogicalSchema.LogicalFieldSchema;
import org.apache.pig.newplan.logical.rules.PushDownForEachFlatten.PushDownForEachFlattenTransformer;
import org.apache.pig.newplan.optimizer.Rule;
import org.apache.pig.newplan.optimizer.Transformer;
/*
* This rule rewrite duplicate column projection into Identity UDF.
* So that we can generate different uid for each column
*/
public class DuplicateForEachColumnRewrite extends Rule {
public DuplicateForEachColumnRewrite(String n) {
super(n, true);
// See comments in ImplicitSplitInserter for the reason to skip listener
setSkipListener(true);
}
@Override
protected OperatorPlan buildPattern() {
LogicalPlan plan = new LogicalPlan();
LogicalRelationalOperator foreach = new LOForEach(plan);
plan.add( foreach );
return plan;
}
@Override
public Transformer getNewTransformer() {
return new DuplicateForEachColumnRewriteTransformer();
}
class DuplicateForEachColumnRewriteTransformer extends Transformer {
private List<LogicalExpressionPlan> expPlansToInsertIdentity = new ArrayList<LogicalExpressionPlan>();
@Override
public boolean check(OperatorPlan matched) throws FrontendException {
LOForEach foreach = (LOForEach)matched.getSources().get(0);
LOGenerate gen = (LOGenerate)foreach.getInnerPlan().getSinks().get(0);
List<LogicalExpressionPlan> expPlans = gen.getOutputPlans();
boolean[] flattens = gen.getFlattenFlags();
List<Long> uidSeen = new ArrayList<Long>();
for (int i=0;i<expPlans.size();i++) {
LogicalExpressionPlan expPlan = expPlans.get(i);
boolean flatten = flattens[i];
LogicalExpression exp = (LogicalExpression)expPlan.getSources().get(0);
if (exp.getFieldSchema()!=null) {
if (flatten && (exp.getFieldSchema().type == DataType.BAG || exp.getFieldSchema().type == DataType.TUPLE)) {
List<LogicalFieldSchema> innerFieldSchemas = null;
if (exp.getFieldSchema().type == DataType.BAG) {
if (exp.getFieldSchema().schema!=null) {
if (exp.getFieldSchema().type == DataType.BAG) {
// assert(fieldSchema.schema.size() == 1 && fieldSchema.schema.getField(0).type == DataType.TUPLE)
if (exp.getFieldSchema().schema.getField(0).schema!=null)
innerFieldSchemas = exp.getFieldSchema().schema.getField(0).schema.getFields();
} else {
if (exp.getFieldSchema().schema!=null)
innerFieldSchemas = exp.getFieldSchema().schema.getFields();
}
}
}
else { // DataType.TUPLE
if (exp.getFieldSchema().schema!=null)
innerFieldSchemas = exp.getFieldSchema().schema.getFields();
}
if (innerFieldSchemas != null) {
for (LogicalFieldSchema innerFieldSchema : innerFieldSchemas) {
long uid = innerFieldSchema.uid;
if (checkAndAdd(uid, uidSeen)) {
// Seen before
expPlansToInsertIdentity.add(expPlan);
break;
}
}
}
}
else {
long uid = exp.getFieldSchema().uid;
if (checkAndAdd(uid, uidSeen)) {
// Seen before
expPlansToInsertIdentity.add(expPlan);
}
}
}
}
if (expPlansToInsertIdentity.isEmpty())
return false;
return true;
}
private boolean checkAndAdd(long uid, List<Long> uidSeen) {
if (uidSeen.contains(uid))
return true;
uidSeen.add(uid);
return false;
}
@Override
public OperatorPlan reportChanges() {
return currentPlan;
}
@Override
public void transform(OperatorPlan matched) throws FrontendException {
for (LogicalExpressionPlan expPlan : expPlansToInsertIdentity) {
LogicalExpression oldRoot = (LogicalExpression)expPlan.getSources().get(0);
UserFuncExpression userFuncExpression = new UserFuncExpression(expPlan, new FuncSpec(IdentityColumn.class.getName()));
expPlan.connect(userFuncExpression, oldRoot);
}
expPlansToInsertIdentity.clear();
// Since we adjust the uid layout, clear all cached uids
UidResetter uidResetter = new UidResetter(currentPlan);
uidResetter.visit();
// Manually regenerate schema since we skip listener
// skip duplicate uid check in schema as it would be fixed in
// only portion of the plan
SchemaResetter schemaResetter = new SchemaResetter(currentPlan, true);
schemaResetter.visit();
}
}
}