/*
* 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,
* 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 com.facebook.presto.operator.aggregation;
import com.facebook.presto.operator.aggregation.state.DigestAndPercentileState;
import com.facebook.presto.spi.block.BlockBuilder;
import com.facebook.presto.spi.function.AggregationFunction;
import com.facebook.presto.spi.function.AggregationState;
import com.facebook.presto.spi.function.CombineFunction;
import com.facebook.presto.spi.function.InputFunction;
import com.facebook.presto.spi.function.OutputFunction;
import com.facebook.presto.spi.function.SqlType;
import com.facebook.presto.spi.type.StandardTypes;
import io.airlift.stats.QuantileDigest;
import static com.facebook.presto.spi.StandardErrorCode.INVALID_FUNCTION_ARGUMENT;
import static com.facebook.presto.spi.type.BigintType.BIGINT;
import static com.facebook.presto.util.Failures.checkCondition;
import static com.google.common.base.Preconditions.checkState;
@AggregationFunction("approx_percentile")
public final class ApproximateLongPercentileAggregations
{
private ApproximateLongPercentileAggregations() {}
@InputFunction
public static void input(@AggregationState DigestAndPercentileState state, @SqlType(StandardTypes.BIGINT) long value, @SqlType(StandardTypes.DOUBLE) double percentile)
{
QuantileDigest digest = state.getDigest();
if (digest == null) {
digest = new QuantileDigest(0.01);
state.setDigest(digest);
state.addMemoryUsage(digest.estimatedInMemorySizeInBytes());
}
state.addMemoryUsage(-digest.estimatedInMemorySizeInBytes());
digest.add(value);
state.addMemoryUsage(digest.estimatedInMemorySizeInBytes());
// use last percentile
state.setPercentile(percentile);
}
@InputFunction
public static void weightedInput(@AggregationState DigestAndPercentileState state, @SqlType(StandardTypes.BIGINT) long value, @SqlType(StandardTypes.BIGINT) long weight, @SqlType(StandardTypes.DOUBLE) double percentile)
{
checkWeight(weight);
QuantileDigest digest = state.getDigest();
if (digest == null) {
digest = new QuantileDigest(0.01);
state.setDigest(digest);
state.addMemoryUsage(digest.estimatedInMemorySizeInBytes());
}
state.addMemoryUsage(-digest.estimatedInMemorySizeInBytes());
digest.add(value, weight);
state.addMemoryUsage(digest.estimatedInMemorySizeInBytes());
// use last percentile
state.setPercentile(percentile);
}
@InputFunction
public static void weightedInput(@AggregationState DigestAndPercentileState state, @SqlType(StandardTypes.BIGINT) long value, @SqlType(StandardTypes.BIGINT) long weight, @SqlType(StandardTypes.DOUBLE) double percentile, @SqlType(StandardTypes.DOUBLE) double accuracy)
{
checkWeight(weight);
QuantileDigest digest = state.getDigest();
if (digest == null) {
if (accuracy > 0 && accuracy < 1) {
digest = new QuantileDigest(accuracy);
}
else {
throw new IllegalArgumentException("Percentile accuracy must be strictly between 0 and 1");
}
state.setDigest(digest);
state.addMemoryUsage(digest.estimatedInMemorySizeInBytes());
}
state.addMemoryUsage(-digest.estimatedInMemorySizeInBytes());
digest.add(value, weight);
state.addMemoryUsage(digest.estimatedInMemorySizeInBytes());
// use last percentile
state.setPercentile(percentile);
}
@CombineFunction
public static void combine(@AggregationState DigestAndPercentileState state, DigestAndPercentileState otherState)
{
QuantileDigest input = otherState.getDigest();
QuantileDigest previous = state.getDigest();
if (previous == null) {
state.setDigest(input);
state.addMemoryUsage(input.estimatedInMemorySizeInBytes());
}
else {
state.addMemoryUsage(-previous.estimatedInMemorySizeInBytes());
previous.merge(input);
state.addMemoryUsage(previous.estimatedInMemorySizeInBytes());
}
state.setPercentile(otherState.getPercentile());
}
@OutputFunction(StandardTypes.BIGINT)
public static void output(@AggregationState DigestAndPercentileState state, BlockBuilder out)
{
QuantileDigest digest = state.getDigest();
double percentile = state.getPercentile();
if (digest == null || digest.getCount() == 0.0) {
out.appendNull();
}
else {
checkState(percentile != -1.0, "Percentile is missing");
checkCondition(0 <= percentile && percentile <= 1, INVALID_FUNCTION_ARGUMENT, "Percentile must be between 0 and 1");
BIGINT.writeLong(out, digest.getQuantile(percentile));
}
}
private static void checkWeight(long weight)
{
checkCondition(weight > 0, INVALID_FUNCTION_ARGUMENT, "percentile weight must be > 0");
}
}