io.druid.query.topn.Historical1AggPooledTopNScanner Maven / Gradle / Ivy
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* Licensed to Metamarkets Group Inc. (Metamarkets) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. Metamarkets 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
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package io.druid.query.topn;
import io.druid.query.aggregation.BufferAggregator;
import io.druid.segment.ColumnValueSelector;
import io.druid.segment.historical.HistoricalCursor;
import io.druid.segment.historical.HistoricalDimensionSelector;
import java.nio.ByteBuffer;
public interface Historical1AggPooledTopNScanner<
DimensionSelectorType extends HistoricalDimensionSelector,
MetricSelectorType extends ColumnValueSelector,
BufferAggregatorType extends BufferAggregator>
{
/**
* @param aggregatorSize number of bytes required by aggregator for a single aggregation
* @param positions a cache for positions in resultsBuffer, where specific (indexed) dimension values are aggregated
* @return number of scanned rows, i. e. number of steps made with the given cursor
*/
long scanAndAggregate(
DimensionSelectorType dimensionSelector,
MetricSelectorType metricSelector,
BufferAggregatorType aggregator,
int aggregatorSize,
HistoricalCursor cursor,
int[] positions,
ByteBuffer resultsBuffer
);
}