/**
* 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.ppd;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.Stack;
import org.apache.hadoop.hive.ql.exec.CommonJoinOperator;
import org.apache.hadoop.hive.ql.exec.FilterOperator;
import org.apache.hadoop.hive.ql.exec.JoinOperator;
import org.apache.hadoop.hive.ql.exec.Operator;
import org.apache.hadoop.hive.ql.exec.OperatorFactory;
import org.apache.hadoop.hive.ql.exec.ReduceSinkOperator;
import org.apache.hadoop.hive.ql.exec.RowSchema;
import org.apache.hadoop.hive.ql.lib.DefaultRuleDispatcher;
import org.apache.hadoop.hive.ql.lib.Dispatcher;
import org.apache.hadoop.hive.ql.lib.GraphWalker;
import org.apache.hadoop.hive.ql.lib.LevelOrderWalker;
import org.apache.hadoop.hive.ql.lib.Node;
import org.apache.hadoop.hive.ql.lib.NodeProcessor;
import org.apache.hadoop.hive.ql.lib.NodeProcessorCtx;
import org.apache.hadoop.hive.ql.lib.Rule;
import org.apache.hadoop.hive.ql.lib.RuleRegExp;
import org.apache.hadoop.hive.ql.optimizer.Transform;
import org.apache.hadoop.hive.ql.parse.ParseContext;
import org.apache.hadoop.hive.ql.parse.SemanticException;
import org.apache.hadoop.hive.ql.plan.ExprNodeDesc;
import org.apache.hadoop.hive.ql.plan.ExprNodeDescUtils;
import org.apache.hadoop.hive.ql.plan.FilterDesc;
import org.apache.hadoop.hive.ql.plan.JoinCondDesc;
import org.apache.hadoop.hive.ql.plan.JoinDesc;
import org.apache.hadoop.hive.ql.plan.OperatorDesc;
/**
* propagates filters to other aliases based on join condition
*/
public class PredicateTransitivePropagate extends Transform {
private ParseContext pGraphContext;
@Override
public ParseContext transform(ParseContext pctx) throws SemanticException {
pGraphContext = pctx;
Map<Rule, NodeProcessor> opRules = new LinkedHashMap<Rule, NodeProcessor>();
opRules.put(new RuleRegExp("R1", "(" +
FilterOperator.getOperatorName() + "%" +
ReduceSinkOperator.getOperatorName() + "%" +
JoinOperator.getOperatorName() + "%)"), new JoinTransitive());
// The dispatcher fires the processor corresponding to the closest matching
// rule and passes the context along
TransitiveContext context = new TransitiveContext();
Dispatcher disp = new DefaultRuleDispatcher(null, opRules, context);
GraphWalker ogw = new LevelOrderWalker(disp, 2);
// Create a list of topop nodes
List<Node> topNodes = new ArrayList<Node>();
topNodes.addAll(pGraphContext.getTopOps().values());
ogw.startWalking(topNodes, null);
Map<ReduceSinkOperator, List<ExprNodeDesc>> newFilters = context.getNewfilters();
// insert new filter between RS and parent of RS
for (Map.Entry<ReduceSinkOperator, List<ExprNodeDesc>> entry : newFilters.entrySet()) {
ReduceSinkOperator reducer = entry.getKey();
Operator<?> parent = reducer.getParentOperators().get(0);
List<ExprNodeDesc> exprs = entry.getValue();
if (parent instanceof FilterOperator) {
exprs = ExprNodeDescUtils.split(((FilterOperator)parent).getConf().getPredicate(), exprs);
ExprNodeDesc merged = ExprNodeDescUtils.mergePredicates(exprs);
((FilterOperator)parent).getConf().setPredicate(merged);
} else {
ExprNodeDesc merged = ExprNodeDescUtils.mergePredicates(exprs);
RowSchema parentRS = parent.getSchema();
Operator<FilterDesc> newFilter = createFilter(reducer, parent, parentRS, merged);
}
}
return pGraphContext;
}
// insert filter operator between target(child) and input(parent)
private Operator<FilterDesc> createFilter(Operator<?> target, Operator<?> parent,
RowSchema parentRS, ExprNodeDesc filterExpr) {
Operator<FilterDesc> filter = OperatorFactory.get(parent.getCompilationOpContext(),
new FilterDesc(filterExpr, false), new RowSchema(parentRS.getSignature()));
filter.getParentOperators().add(parent);
filter.getChildOperators().add(target);
parent.replaceChild(target, filter);
target.replaceParent(parent, filter);
return filter;
}
private static class TransitiveContext implements NodeProcessorCtx {
private final Map<CommonJoinOperator, int[][]> filterPropagates;
private final Map<ReduceSinkOperator, List<ExprNodeDesc>> newFilters;
public TransitiveContext() {
filterPropagates = new HashMap<CommonJoinOperator, int[][]>();
newFilters = new HashMap<ReduceSinkOperator, List<ExprNodeDesc>>();
}
public Map<CommonJoinOperator, int[][]> getFilterPropagates() {
return filterPropagates;
}
public Map<ReduceSinkOperator, List<ExprNodeDesc>> getNewfilters() {
return newFilters;
}
}
private static class JoinTransitive implements NodeProcessor {
@Override
public Object process(Node nd, Stack<Node> stack, NodeProcessorCtx procCtx,
Object... nodeOutputs) throws SemanticException {
@SuppressWarnings("unchecked")
CommonJoinOperator<JoinDesc> join = (CommonJoinOperator) nd;
ReduceSinkOperator source = (ReduceSinkOperator) stack.get(stack.size() - 2);
FilterOperator filter = (FilterOperator) stack.get(stack.size() - 3);
int srcPos = join.getParentOperators().indexOf(source);
TransitiveContext context = (TransitiveContext) procCtx;
Map<CommonJoinOperator, int[][]> filterPropagates = context.getFilterPropagates();
Map<ReduceSinkOperator, List<ExprNodeDesc>> newFilters = context.getNewfilters();
int[][] targets = filterPropagates.get(join);
if (targets == null) {
filterPropagates.put(join, targets = getTargets(join));
}
List<Operator<? extends OperatorDesc>> parents = join.getParentOperators();
for (int targetPos : targets[srcPos]) {
ReduceSinkOperator target = (ReduceSinkOperator) parents.get(targetPos);
List<ExprNodeDesc> sourceKeys = source.getConf().getKeyCols();
List<ExprNodeDesc> targetKeys = target.getConf().getKeyCols();
ExprNodeDesc predicate = filter.getConf().getPredicate();
ExprNodeDesc replaced = ExprNodeDescUtils.replace(predicate, sourceKeys, targetKeys);
if (replaced != null && !filterExists(target, replaced)) {
List<ExprNodeDesc> prev = newFilters.get(target);
if (prev == null) {
newFilters.put(target, ExprNodeDescUtils.split(replaced));
} else {
ExprNodeDescUtils.split(replaced, prev);
}
}
}
return null;
}
// check same filter exists already
private boolean filterExists(ReduceSinkOperator target, ExprNodeDesc replaced) {
Operator<?> operator = target.getParentOperators().get(0);
for (; operator instanceof FilterOperator; operator = operator.getParentOperators().get(0)) {
ExprNodeDesc predicate = ((FilterOperator) operator).getConf().getPredicate();
if (ExprNodeDescUtils.containsPredicate(predicate, replaced)) {
return true;
}
}
return false;
}
}
// calculate filter propagation directions for each alias
// L<->R for inner/semi join, L->R for left outer join, R->L for right outer join
public static int[][] getTargets(CommonJoinOperator<JoinDesc> join) {
JoinCondDesc[] conds = join.getConf().getConds();
int aliases = conds.length + 1;
Vectors vector = new Vectors(aliases);
for (JoinCondDesc cond : conds) {
int left = cond.getLeft();
int right = cond.getRight();
switch (cond.getType()) {
case JoinDesc.INNER_JOIN:
case JoinDesc.LEFT_SEMI_JOIN:
vector.add(left, right);
vector.add(right, left);
break;
case JoinDesc.LEFT_OUTER_JOIN:
vector.add(left, right);
break;
case JoinDesc.RIGHT_OUTER_JOIN:
vector.add(right, left);
break;
case JoinDesc.FULL_OUTER_JOIN:
break;
}
}
int[][] result = new int[aliases][];
for (int pos = 0 ; pos < aliases; pos++) {
// find all targets recursively
result[pos] = vector.traverse(pos);
}
return result;
}
private static class Vectors {
private final Set<Integer>[] vector;
@SuppressWarnings("unchecked")
public Vectors(int length) {
vector = new Set[length];
}
public void add(int from, int to) {
if (vector[from] == null) {
vector[from] = new HashSet<Integer>();
}
vector[from].add(to);
}
public int[] traverse(int pos) {
Set<Integer> targets = new HashSet<Integer>();
traverse(targets, pos);
return toArray(targets, pos);
}
private int[] toArray(Set<Integer> values, int pos) {
values.remove(pos);
int index = 0;
int[] result = new int[values.size()];
for (int value : values) {
result[index++] = value;
}
return result;
}
private void traverse(Set<Integer> targets, int pos) {
if (vector[pos] == null) {
return;
}
for (int target : vector[pos]) {
if (targets.add(target)) {
traverse(targets, target);
}
}
}
}
}