/**
* 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.optiq.rules;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;
import org.apache.hadoop.hive.metastore.api.FieldSchema;
import org.apache.hadoop.hive.ql.exec.FunctionRegistry;
import org.apache.hadoop.hive.ql.optimizer.optiq.RelOptHiveTable;
import org.apache.hadoop.hive.ql.optimizer.optiq.translator.SqlFunctionConverter;
import org.apache.hadoop.hive.ql.udf.generic.GenericUDF;
import org.eigenbase.relopt.RelOptCluster;
import org.eigenbase.reltype.RelDataType;
import org.eigenbase.reltype.RelDataTypeField;
import org.eigenbase.rex.RexCall;
import org.eigenbase.rex.RexInputRef;
import org.eigenbase.rex.RexLiteral;
import org.eigenbase.rex.RexNode;
import org.eigenbase.rex.RexVisitorImpl;
import org.eigenbase.sql.fun.SqlStdOperatorTable;
import org.eigenbase.util.Pair;
public class PartitionPruner {
/**
* Breaks the predicate into 2 pieces. The first piece is the expressions that
* only contain partition columns and can be used for Partition Pruning; the
* second piece is the predicates that are left.
*
* @param cluster
* @param hiveTable
* @param predicate
* @return a Pair of expressions, each of which maybe null. The 1st predicate
* is expressions that only contain partition columns; the 2nd
* predicate contains the remaining predicates.
*/
public static Pair<RexNode, RexNode> extractPartitionPredicates(
RelOptCluster cluster, RelOptHiveTable hiveTable, RexNode predicate) {
RexNode partitionPruningPred = predicate
.accept(new ExtractPartPruningPredicate(cluster, hiveTable));
RexNode remainingPred = predicate.accept(new ExtractRemainingPredicate(
cluster, partitionPruningPred));
return new Pair<RexNode, RexNode>(partitionPruningPred, remainingPred);
}
public static class ExtractPartPruningPredicate extends
RexVisitorImpl<RexNode> {
final RelOptHiveTable hiveTable;
final RelDataType rType;
final Set<String> partCols;
final RelOptCluster cluster;
public ExtractPartPruningPredicate(RelOptCluster cluster,
RelOptHiveTable hiveTable) {
super(true);
this.hiveTable = hiveTable;
rType = hiveTable.getRowType();
List<FieldSchema> pfs = hiveTable.getHiveTableMD().getPartCols();
partCols = new HashSet<String>();
for (FieldSchema pf : pfs) {
partCols.add(pf.getName());
}
this.cluster = cluster;
}
@Override
public RexNode visitLiteral(RexLiteral literal) {
return literal;
}
@Override
public RexNode visitInputRef(RexInputRef inputRef) {
RelDataTypeField f = rType.getFieldList().get(inputRef.getIndex());
if (partCols.contains(f.getName())) {
return inputRef;
} else {
return null;
}
}
@Override
public RexNode visitCall(RexCall call) {
if (!deep) {
return null;
}
List<RexNode> args = new LinkedList<RexNode>();
boolean argsPruned = false;
GenericUDF hiveUDF = SqlFunctionConverter.getHiveUDF(call.getOperator(),
call.getType(), call.operands.size());
if (hiveUDF != null &&
!FunctionRegistry.isDeterministic(hiveUDF)) {
return null;
}
for (RexNode operand : call.operands) {
RexNode n = operand.accept(this);
if (n != null) {
args.add(n);
} else {
argsPruned = true;
}
}
if (call.getOperator() != SqlStdOperatorTable.AND) {
return argsPruned ? null : call;
} else {
if (args.size() == 0) {
return null;
} else if (args.size() == 1) {
return args.get(0);
} else {
return cluster.getRexBuilder().makeCall(call.getOperator(), args);
}
}
}
}
public static class ExtractRemainingPredicate extends RexVisitorImpl<RexNode> {
List<RexNode> pruningPredicates;
final RelOptCluster cluster;
public ExtractRemainingPredicate(RelOptCluster cluster,
RexNode partPruningExpr) {
super(true);
this.cluster = cluster;
pruningPredicates = new ArrayList<RexNode>();
flattenPredicates(partPruningExpr);
}
private void flattenPredicates(RexNode r) {
if (r instanceof RexCall
&& ((RexCall) r).getOperator() == SqlStdOperatorTable.AND) {
for (RexNode c : ((RexCall) r).getOperands()) {
flattenPredicates(c);
}
} else {
pruningPredicates.add(r);
}
}
@Override
public RexNode visitLiteral(RexLiteral literal) {
return literal;
}
@Override
public RexNode visitInputRef(RexInputRef inputRef) {
return inputRef;
}
@Override
public RexNode visitCall(RexCall call) {
if (!deep) {
return null;
}
if (call.getOperator() != SqlStdOperatorTable.AND) {
if (pruningPredicates.contains(call)) {
return null;
} else {
return call;
}
}
List<RexNode> args = new LinkedList<RexNode>();
for (RexNode operand : call.operands) {
RexNode n = operand.accept(this);
if (n != null) {
args.add(n);
}
}
if (args.size() == 0) {
return null;
} else if (args.size() == 1) {
return args.get(0);
} else {
return cluster.getRexBuilder().makeCall(call.getOperator(), args);
}
}
}
}