/*
* 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.phoenix.execute;
import java.sql.SQLException;
import java.util.Collections;
import java.util.List;
import org.apache.hadoop.hbase.client.Scan;
import org.apache.phoenix.compile.GroupByCompiler.GroupBy;
import org.apache.phoenix.compile.OrderByCompiler.OrderBy;
import org.apache.phoenix.compile.RowProjector;
import org.apache.phoenix.compile.StatementContext;
import org.apache.phoenix.coprocessor.BaseScannerRegionObserver;
import org.apache.phoenix.coprocessor.UngroupedAggregateRegionObserver;
import org.apache.phoenix.expression.Expression;
import org.apache.phoenix.expression.OrderByExpression;
import org.apache.phoenix.expression.RowKeyExpression;
import org.apache.phoenix.expression.aggregator.Aggregators;
import org.apache.phoenix.iterate.AggregatingResultIterator;
import org.apache.phoenix.iterate.ConcatResultIterator;
import org.apache.phoenix.iterate.DistinctAggregatingResultIterator;
import org.apache.phoenix.iterate.FilterAggregatingResultIterator;
import org.apache.phoenix.iterate.GroupedAggregatingResultIterator;
import org.apache.phoenix.iterate.LimitingResultIterator;
import org.apache.phoenix.iterate.MergeSortRowKeyResultIterator;
import org.apache.phoenix.iterate.OrderedAggregatingResultIterator;
import org.apache.phoenix.iterate.OrderedResultIterator;
import org.apache.phoenix.iterate.ParallelIterators;
import org.apache.phoenix.iterate.ParallelIterators.ParallelIteratorFactory;
import org.apache.phoenix.iterate.PeekingResultIterator;
import org.apache.phoenix.iterate.ResultIterator;
import org.apache.phoenix.iterate.SequenceResultIterator;
import org.apache.phoenix.iterate.SpoolingResultIterator;
import org.apache.phoenix.iterate.UngroupedAggregatingResultIterator;
import org.apache.phoenix.parse.FilterableStatement;
import org.apache.phoenix.query.KeyRange;
import org.apache.phoenix.query.QueryServices;
import org.apache.phoenix.query.QueryServicesOptions;
import org.apache.phoenix.schema.PDataType;
import org.apache.phoenix.schema.TableRef;
/**
*
* Query plan for aggregating queries
*
*
* @since 0.1
*/
public class AggregatePlan extends BaseQueryPlan {
private final Aggregators aggregators;
private final Expression having;
private List<KeyRange> splits;
public AggregatePlan(
StatementContext context, FilterableStatement statement, TableRef table, RowProjector projector,
Integer limit, OrderBy orderBy, ParallelIteratorFactory parallelIteratorFactory, GroupBy groupBy,
Expression having) {
super(context, statement, table, projector, context.getBindManager().getParameterMetaData(), limit, orderBy, groupBy, parallelIteratorFactory);
this.having = having;
this.aggregators = context.getAggregationManager().getAggregators();
}
public Expression getHaving() {
return having;
}
@Override
public List<KeyRange> getSplits() {
return splits;
}
private static class OrderingResultIteratorFactory implements ParallelIteratorFactory {
private final QueryServices services;
public OrderingResultIteratorFactory(QueryServices services) {
this.services = services;
}
@Override
public PeekingResultIterator newIterator(StatementContext context, ResultIterator scanner, Scan scan) throws SQLException {
Expression expression = RowKeyExpression.INSTANCE;
OrderByExpression orderByExpression = new OrderByExpression(expression, false, true);
int threshold = services.getProps().getInt(QueryServices.SPOOL_THRESHOLD_BYTES_ATTRIB, QueryServicesOptions.DEFAULT_SPOOL_THRESHOLD_BYTES);
return new OrderedResultIterator(scanner, Collections.<OrderByExpression>singletonList(orderByExpression), threshold);
}
}
private static class WrappingResultIteratorFactory implements ParallelIteratorFactory {
private final ParallelIteratorFactory innerFactory;
private final ParallelIteratorFactory outerFactory;
public WrappingResultIteratorFactory(ParallelIteratorFactory innerFactory, ParallelIteratorFactory outerFactory) {
this.innerFactory = innerFactory;
this.outerFactory = outerFactory;
}
@Override
public PeekingResultIterator newIterator(StatementContext context, ResultIterator scanner, Scan scan) throws SQLException {
PeekingResultIterator iterator = innerFactory.newIterator(context, scanner, scan);
return outerFactory.newIterator(context, iterator, scan);
}
}
private ParallelIteratorFactory wrapParallelIteratorFactory () {
ParallelIteratorFactory innerFactory;
QueryServices services = context.getConnection().getQueryServices();
if (groupBy.isEmpty() || groupBy.isOrderPreserving()) {
innerFactory = new SpoolingResultIterator.SpoolingResultIteratorFactory(services);
} else {
innerFactory = new OrderingResultIteratorFactory(services);
}
if (parallelIteratorFactory == null) {
return innerFactory;
}
// wrap any existing parallelIteratorFactory
return new WrappingResultIteratorFactory(innerFactory, parallelIteratorFactory);
}
@Override
protected ResultIterator newIterator() throws SQLException {
if (groupBy.isEmpty()) {
UngroupedAggregateRegionObserver.serializeIntoScan(context.getScan());
} else if (limit != null && orderBy.getOrderByExpressions().isEmpty() && having == null
&& ( ( statement.isDistinct() && ! statement.isAggregate() )
|| ( ! statement.isDistinct() && ( context.getAggregationManager().isEmpty()
|| BaseScannerRegionObserver.KEY_ORDERED_GROUP_BY_EXPRESSIONS.equals(groupBy.getScanAttribName()) ) ) ) ) {
/*
* Optimization to early exit from the scan for a GROUP BY or DISTINCT with a LIMIT.
* We may exit early according to the LIMIT specified if the query has:
* 1) No ORDER BY clause (or the ORDER BY was optimized out). We cannot exit
* early if there's an ORDER BY because the first group may be found last
* in the scan.
* 2) No HAVING clause, since we execute the HAVING on the client side. The LIMIT
* needs to be evaluated *after* the HAVING.
* 3) DISTINCT clause with no GROUP BY. We cannot exit early if there's a
* GROUP BY, as the GROUP BY is processed on the client-side post aggregation
* if a DISTNCT has a GROUP BY. Otherwise, since there are no aggregate
* functions in a DISTINCT, we can exit early regardless of if the
* groups are in row key order or unordered.
* 4) GROUP BY clause with no aggregate functions. This is in the same category
* as (3). If we're using aggregate functions, we need to look at all the
* rows, as otherwise we'd exit early with incorrect aggregate function
* calculations.
* 5) GROUP BY clause along the pk axis, as the rows are processed in row key
* order, so we can early exit, even when aggregate functions are used, as
* the rows in the group are contiguous.
*/
context.getScan().setAttribute(BaseScannerRegionObserver.GROUP_BY_LIMIT, PDataType.INTEGER.toBytes(limit));
}
ParallelIterators parallelIterators = new ParallelIterators(context, tableRef, statement, projection, groupBy, null, wrapParallelIteratorFactory());
splits = parallelIterators.getSplits();
AggregatingResultIterator aggResultIterator;
// No need to merge sort for ungrouped aggregation
if (groupBy.isEmpty()) {
aggResultIterator = new UngroupedAggregatingResultIterator(new ConcatResultIterator(parallelIterators), aggregators);
} else {
aggResultIterator = new GroupedAggregatingResultIterator(new MergeSortRowKeyResultIterator(parallelIterators), aggregators);
}
if (having != null) {
aggResultIterator = new FilterAggregatingResultIterator(aggResultIterator, having);
}
if (statement.isDistinct() && statement.isAggregate()) { // Dedup on client if select distinct and aggregation
aggResultIterator = new DistinctAggregatingResultIterator(aggResultIterator, getProjector());
}
ResultIterator resultScanner = aggResultIterator;
if (orderBy.getOrderByExpressions().isEmpty()) {
if (limit != null) {
resultScanner = new LimitingResultIterator(aggResultIterator, limit);
}
} else {
int thresholdBytes = context.getConnection().getQueryServices().getProps().getInt(
QueryServices.SPOOL_THRESHOLD_BYTES_ATTRIB, QueryServicesOptions.DEFAULT_SPOOL_THRESHOLD_BYTES);
resultScanner = new OrderedAggregatingResultIterator(aggResultIterator, orderBy.getOrderByExpressions(), thresholdBytes, limit);
}
if (context.getSequenceManager().getSequenceCount() > 0) {
resultScanner = new SequenceResultIterator(resultScanner, context.getSequenceManager());
}
return resultScanner;
}
}