org.apache.druid.segment.index.DictionaryRangeScanningBitmapIndex Maven / Gradle / Ivy
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/*
* 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.druid.segment.index;
import org.apache.druid.query.BitmapResultFactory;
import org.apache.druid.segment.column.ColumnConfig;
import javax.annotation.Nullable;
/**
* Common {@link BitmapColumnIndex} implementation for indexes which need to scan a range of values. Contains logic
* to skip computing indexes with {@link #computeBitmapResult(BitmapResultFactory, int, int, boolean)} if
* {@link #rangeSize} is larger than {@link #sizeScale} multiplied by the number of selected rows. Numeric range
* indexes will typically want to set {@link #sizeScale} to a double closer to 0.0 than to 1.0 because numeric
* comparisons are relatively cheap compared to bitmap operations. Most numerical implementations should use the
* value of {@link ColumnConfig#skipValueRangeIndexScale()}.
*
* Other implementations should adjust {@link #sizeScale} as appropriate for the expense of the value matcher compared
* to the expense of the bitmap operations.
*/
public abstract class DictionaryRangeScanningBitmapIndex extends SimpleImmutableBitmapDelegatingIterableIndex
{
private final double sizeScale;
private final int rangeSize;
public DictionaryRangeScanningBitmapIndex(double sizeScale, int rangeSize)
{
this.sizeScale = sizeScale;
this.rangeSize = rangeSize;
}
@Nullable
@Override
public final T computeBitmapResult(
BitmapResultFactory bitmapResultFactory,
int applyRowCount,
int totalRowCount,
boolean includeUnknown
)
{
final int scale = (int) Math.ceil(sizeScale * applyRowCount);
if (rangeSize > scale) {
return null;
}
return computeBitmapResult(bitmapResultFactory, includeUnknown);
}
}