org.apache.flink.table.plan.stats.ColumnStats Maven / Gradle / Ivy
/*
* 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.flink.table.plan.stats;
import org.apache.flink.annotation.PublicEvolving;
import java.util.ArrayList;
import java.util.List;
import java.util.Objects;
import java.util.function.BinaryOperator;
/** Column statistics. */
@PublicEvolving
public final class ColumnStats {
/** number of distinct values. */
private final Long ndv;
/** number of nulls. */
private final Long nullCount;
/** average length of column values. */
private final Double avgLen;
/** max length of column values. */
private final Integer maxLen;
/**
* Deprecated because not well supported comparable type, e.g. {@link java.util.Date}, {@link
* java.sql.Timestamp}.
*/
@Deprecated private final Number maxValue;
/** max value of column values, null if the value is unknown or not comparable. */
private final Comparable max;
/**
* Deprecated because not well supported comparable type, e.g. {@link java.util.Date}, {@link
* java.sql.Timestamp}.
*/
@Deprecated private final Number minValue;
/** min value of column values, null if the value is unknown or not comparable. */
private final Comparable min;
/**
* Deprecated because Number type max/min is not well supported comparable type, e.g. {@link
* java.util.Date}, {@link java.sql.Timestamp}. please use {@link ColumnStats.Builder} to
* construct ColumnStats instance.
*/
@Deprecated
public ColumnStats(
Long ndv, Long nullCount, Double avgLen, Integer maxLen, Number max, Number min) {
this.ndv = ndv;
this.nullCount = nullCount;
this.avgLen = avgLen;
this.maxLen = maxLen;
this.maxValue = max;
this.minValue = min;
this.max = null;
this.min = null;
}
/**
* Private because to avoid "cannot resolve constructor" error. please use {@link
* ColumnStats.Builder} to construct ColumnStats instance. could change to public if the
* deprecated constructor is removed in the future.
*/
private ColumnStats(
Long ndv,
Long nullCount,
Double avgLen,
Integer maxLen,
Comparable max,
Comparable min) {
this.ndv = ndv;
this.nullCount = nullCount;
this.avgLen = avgLen;
this.maxLen = maxLen;
this.max = max;
this.min = min;
this.maxValue = null;
this.minValue = null;
}
public Long getNdv() {
return ndv;
}
public Long getNullCount() {
return nullCount;
}
public Double getAvgLen() {
return avgLen;
}
public Integer getMaxLen() {
return maxLen;
}
/**
* Deprecated because Number type max/min is not well supported comparable type, e.g. {@link
* java.util.Date}, {@link java.sql.Timestamp}.
*
* Returns null if this instance is constructed by {@link ColumnStats.Builder}.
*/
@Deprecated
public Number getMaxValue() {
return maxValue;
}
/**
* Returns null if this instance is constructed by {@link ColumnStats#ColumnStats(Long, Long,
* Double, Integer, Number, Number)}.
*/
public Comparable getMax() {
return max;
}
/**
* Deprecated because Number type max/min is not well supported comparable type, e.g. {@link
* java.util.Date}, {@link java.sql.Timestamp}.
*
*
Returns null if this instance is constructed by {@link ColumnStats.Builder}.
*/
@Deprecated
public Number getMinValue() {
return minValue;
}
/**
* Returns null if this instance is constructed by {@link ColumnStats#ColumnStats(Long, Long,
* Double, Integer, Number, Number)}.
*/
public Comparable getMin() {
return min;
}
public String toString() {
List columnStats = new ArrayList<>();
if (ndv != null) {
columnStats.add("ndv=" + ndv);
}
if (nullCount != null) {
columnStats.add("nullCount=" + nullCount);
}
if (avgLen != null) {
columnStats.add("avgLen=" + avgLen);
}
if (maxLen != null) {
columnStats.add("maxLen=" + maxLen);
}
if (max != null) {
columnStats.add("max=" + max);
}
if (maxValue != null) {
columnStats.add("max=" + maxValue);
}
if (min != null) {
columnStats.add("min=" + min);
}
if (minValue != null) {
columnStats.add("min=" + minValue);
}
String columnStatsStr = String.join(", ", columnStats);
return "ColumnStats(" + columnStatsStr + ")";
}
/**
* Create a deep copy of "this" instance.
*
* @return a deep copy
*/
public ColumnStats copy() {
if (maxValue != null || minValue != null) {
return new ColumnStats(
this.ndv,
this.nullCount,
this.avgLen,
this.maxLen,
this.maxValue,
this.minValue);
} else {
return new ColumnStats(
this.ndv, this.nullCount, this.avgLen, this.maxLen, this.max, this.min);
}
}
/**
* Merges two column stats. When the stats are unknown, whatever the other are, we need return
* unknown stats. The unknown definition for column stats is null.
*
* @param other The other column stats to merge.
* @return The merged column stats.
*/
public ColumnStats merge(ColumnStats other) {
Long ndv = combineIfNonNull(Long::sum, this.ndv, other.ndv);
Long nullCount = combineIfNonNull(Long::sum, this.nullCount, other.nullCount);
Double avgLen = combineIfNonNull((a1, a2) -> (a1 + a2) / 2, this.avgLen, other.avgLen);
Integer maxLen = combineIfNonNull(Math::max, this.maxLen, other.maxLen);
Number maxValue =
combineIfNonNull(
(n1, n2) -> n1.doubleValue() > n2.doubleValue() ? n1 : n2,
this.maxValue,
other.maxValue);
Number minValue =
combineIfNonNull(
(n1, n2) -> n1.doubleValue() < n2.doubleValue() ? n1 : n2,
this.minValue,
other.minValue);
@SuppressWarnings("unchecked")
Comparable max =
combineIfNonNull(
(c1, c2) -> ((Comparable) c1).compareTo(c2) > 0 ? c1 : c2,
this.max,
other.max);
@SuppressWarnings("unchecked")
Comparable min =
combineIfNonNull(
(c1, c2) -> ((Comparable) c1).compareTo(c2) < 0 ? c1 : c2,
this.min,
other.min);
if (max != null || min != null) {
return new ColumnStats(ndv, nullCount, avgLen, maxLen, max, min);
} else {
return new ColumnStats(ndv, nullCount, avgLen, maxLen, maxValue, minValue);
}
}
@Override
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (o == null || getClass() != o.getClass()) {
return false;
}
ColumnStats that = (ColumnStats) o;
return Objects.equals(ndv, that.ndv)
&& Objects.equals(nullCount, that.nullCount)
&& Objects.equals(avgLen, that.avgLen)
&& Objects.equals(maxLen, that.maxLen)
&& Objects.equals(maxValue, that.maxValue)
&& Objects.equals(max, that.max)
&& Objects.equals(minValue, that.minValue)
&& Objects.equals(min, that.min);
}
@Override
public int hashCode() {
return Objects.hash(ndv, nullCount, avgLen, maxLen, maxValue, max, minValue, min);
}
private static T combineIfNonNull(BinaryOperator op, T t1, T t2) {
if (t1 == null || t2 == null) {
return null;
}
return op.apply(t1, t2);
}
/** ColumnStats builder. */
public static class Builder {
private Long ndv = null;
private Long nullCount = null;
private Double avgLen = null;
private Integer maxLen = null;
private Comparable max;
private Comparable min;
public static Builder builder() {
return new Builder();
}
public Builder setNdv(Long ndv) {
this.ndv = ndv;
return this;
}
public Builder setNullCount(Long nullCount) {
this.nullCount = nullCount;
return this;
}
public Builder setAvgLen(Double avgLen) {
this.avgLen = avgLen;
return this;
}
public Builder setMaxLen(Integer maxLen) {
this.maxLen = maxLen;
return this;
}
public Builder setMax(Comparable max) {
this.max = max;
return this;
}
public Builder setMin(Comparable min) {
this.min = min;
return this;
}
public ColumnStats build() {
return new ColumnStats(ndv, nullCount, avgLen, maxLen, max, min);
}
}
}