io.questdb.griffin.engine.functions.groupby.CountDistinctStringGroupByFunction Maven / Gradle / Ivy

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 *  Copyright (c) 2014-2019 Appsicle
 *  Copyright (c) 2019-2024 QuestDB
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 *  Licensed 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,
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package io.questdb.griffin.engine.functions.groupby;

import io.questdb.cairo.ArrayColumnTypes;
import io.questdb.cairo.ColumnType;
import io.questdb.cairo.map.MapValue;
import io.questdb.cairo.sql.Function;
import io.questdb.cairo.sql.Record;
import io.questdb.griffin.engine.functions.GroupByFunction;
import io.questdb.griffin.engine.functions.LongFunction;
import io.questdb.griffin.engine.functions.UnaryFunction;
import io.questdb.std.CompactCharSequenceHashSet;
import io.questdb.std.Numbers;
import io.questdb.std.ObjList;

public class CountDistinctStringGroupByFunction extends LongFunction implements UnaryFunction, GroupByFunction {
    private final Function arg;
    private final int setInitialCapacity;
    private final double setLoadFactor;
    private final ObjList sets = new ObjList<>();
    private int setIndex = 0;
    private int valueIndex;
    private final boolean earlyExit;

    public CountDistinctStringGroupByFunction(Function arg, int setInitialCapacity, double setLoadFactor) {
        this.arg = arg;
        this.setInitialCapacity = setInitialCapacity;
        this.setLoadFactor = setLoadFactor;
        this.earlyExit = arg.isConstant();
    }

    @Override
    public void clear() {
        sets.clear();
        setIndex = 0;
    }

    @Override
    public void computeFirst(MapValue mapValue, Record record, long rowId) {
        final CompactCharSequenceHashSet set;
        if (sets.size() <= setIndex) {
            sets.extendAndSet(setIndex, set = new CompactCharSequenceHashSet(setInitialCapacity, setLoadFactor));
        } else {
            set = sets.getQuick(setIndex);
            set.clear();
        }

        final CharSequence val = arg.getStrA(record);
        if (val != null) {
            set.add(val);
            mapValue.putLong(valueIndex, 1L);
        } else {
            mapValue.putLong(valueIndex, 0L);
        }
        mapValue.putInt(valueIndex + 1, setIndex++);
    }

    @Override
    public boolean earlyExit(MapValue mapValue) {
        return earlyExit;
    }

    @Override
    public boolean isEarlyExitSupported() {
        return earlyExit;
    }

    @Override
    public void computeNext(MapValue mapValue, Record record, long rowId) {
        final CompactCharSequenceHashSet set = sets.getQuick(mapValue.getInt(valueIndex + 1));
        final CharSequence val = arg.getStrA(record);
        if (val != null) {
            final int index = set.keyIndex(val);
            if (index < 0) {
                return;
            }
            set.addAt(index, val);
            mapValue.addLong(valueIndex, 1);
        }
    }

    @Override
    public Function getArg() {
        return arg;
    }

    @Override
    public long getLong(Record rec) {
        return rec.getLong(valueIndex);
    }

    @Override
    public String getName() {
        return "count_distinct";
    }

    @Override
    public int getValueIndex() {
        return valueIndex;
    }

    @Override
    public void initValueIndex(int valueIndex) {
        this.valueIndex = valueIndex;
    }

    @Override
    public void initValueTypes(ArrayColumnTypes columnTypes) {
        this.valueIndex = columnTypes.getColumnCount();
        columnTypes.add(ColumnType.LONG);
        columnTypes.add(ColumnType.INT);
    }

    @Override
    public boolean isConstant() {
        return false;
    }

    @Override
    public boolean isThreadSafe() {
        return false;
    }

    @Override
    public void setEmpty(MapValue mapValue) {
        mapValue.putLong(valueIndex, 0L);
    }

    @Override
    public void setLong(MapValue mapValue, long value) {
        mapValue.putLong(valueIndex, value);
    }

    @Override
    public void setNull(MapValue mapValue) {
        mapValue.putLong(valueIndex, Numbers.LONG_NULL);
    }

    @Override
    public boolean supportsParallelism() {
        return false;
    }

    @Override
    public void toTop() {
        UnaryFunction.super.toTop();
        setIndex = 0;
    }
}