org.apache.hadoop.dynamodb.IopsController.java Source code

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Here is the source code for org.apache.hadoop.dynamodb.IopsController.java

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/**
 * Copyright 2012-2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file
 * except in compliance with the License. A copy of the License is located at
 *
 *  http://aws.amazon.com/apache2.0/
 *
 * or in the "LICENSE.TXT" file accompanying this file. This file 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.hadoop.dynamodb;

import static org.apache.hadoop.dynamodb.DynamoDBConstants.DEFAULT_AVERAGE_ITEM_SIZE_IN_BYTES;

import org.joda.time.DateTime;
import org.joda.time.DateTimeZone;
import org.joda.time.Duration;

import java.util.Random;

public class IopsController {

    private final IopsCalculator iopsCalculator;
    private final Duration iopsUpdateDuration;
    private final DynamoDBOperationType operationType;
    private DateTime lastUpdateTime;
    private double targetIops;
    private double targetItemsPerSecond;

    public IopsController(IopsCalculator iopsCalculator, double averageItemSizeInBytes,
            DynamoDBOperationType operationType) {
        this.iopsCalculator = iopsCalculator;
        this.operationType = operationType;

        iopsUpdateDuration = getUpdateDuration();
        lastUpdateTime = getCurrentTime();
        targetIops = iopsCalculator.calculateTargetIops();

        if (averageItemSizeInBytes < 1) {
            averageItemSizeInBytes = DEFAULT_AVERAGE_ITEM_SIZE_IN_BYTES;
        }
        double bytesPerIO = (DynamoDBOperationType.READ == operationType)
                ? DynamoDBConstants.BYTES_PER_READ_CAPACITY_UNIT
                : DynamoDBConstants.BYTES_PER_WRITE_CAPACITY_UNIT;
        double itemsPerIO = bytesPerIO / averageItemSizeInBytes;
        targetItemsPerSecond = calculateTargetItemsPerSecond(operationType, targetIops, itemsPerIO);
    }

    public static double calculateTargetItemsPerSecond(DynamoDBOperationType operationType, double targetIops,
            double itemsPerIO) {
        // Minimum required IOPS for write is 1.0 even for small items
        if (DynamoDBOperationType.WRITE.equals(operationType) && itemsPerIO > 1.0) {
            itemsPerIO = 1.0;
        }

        double result = targetIops * itemsPerIO;
        if (result < 1) {
            result = 1;
        }
        return result;
    }

    public long getTargetItemsPerSecond() {
        return (long) targetItemsPerSecond;
    }

    public void update(long itemsPerSecond, double iopsConsumed) {
        DateTime currentTime = getCurrentTime();
        if (currentTime.isAfter(lastUpdateTime.plus(iopsUpdateDuration))) {
            lastUpdateTime = currentTime;
            targetIops = iopsCalculator.calculateTargetIops();
        }

        if (itemsPerSecond != 0 && iopsConsumed != 0) {
            double itemsPerIO = itemsPerSecond / iopsConsumed;
            targetItemsPerSecond = calculateTargetItemsPerSecond(operationType, targetIops, itemsPerIO);
        }
    }

    /**
     * This method generates a random duration between 5 and 10 minutes. This is the duration used
     * to get the updated capacity unit information from the table.
     */
    private Duration getUpdateDuration() {
        Random random = new Random(System.currentTimeMillis());
        long randomDuration = random.nextInt(5 * 60 * 1000);
        return Duration.standardMinutes(5).plus(randomDuration);
    }

    private DateTime getCurrentTime() {
        return new DateTime(DateTimeZone.UTC);
    }

}