org.apache.hadoop.hive.ql.exec.mapjoin.MapJoinMemoryExhaustionHandler.java Source code

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Here is the source code for org.apache.hadoop.hive.ql.exec.mapjoin.MapJoinMemoryExhaustionHandler.java

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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.hadoop.hive.ql.exec.mapjoin;

import java.lang.management.ManagementFactory;
import java.lang.management.MemoryMXBean;
import java.text.NumberFormat;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hive.ql.exec.Utilities;
import org.apache.hadoop.hive.ql.session.SessionState.LogHelper;

/**
 * Handles the logic around deciding when to throw an MapJoinMemoryExhaustionException
 * for HashTableSinkOperator.
 */
public class MapJoinMemoryExhaustionHandler {
    private static final Log LOG = LogFactory.getLog(MapJoinMemoryExhaustionHandler.class);

    public final MemoryMXBean memoryMXBean;

    /**
     * The percentage of overall heap that the JVM is allowed
     * to allocate before failing a MapJoin local task.
     */
    private final double maxMemoryUsage;
    /**
     * The max heap of the JVM in bytes.
     */
    private final long maxHeapSize;
    private final LogHelper console;
    private final NumberFormat percentageNumberFormat;

    /**
     * Constructor expects a LogHelper object in addition to the max percent
     * of heap memory which can be consumed before a MapJoinMemoryExhaustionException
     * is thrown.
     */
    public MapJoinMemoryExhaustionHandler(LogHelper console, double maxMemoryUsage) {
        this.console = console;
        this.maxMemoryUsage = maxMemoryUsage;
        this.memoryMXBean = ManagementFactory.getMemoryMXBean();
        this.maxHeapSize = getMaxHeapSize(memoryMXBean);
        percentageNumberFormat = NumberFormat.getInstance();
        percentageNumberFormat.setMinimumFractionDigits(2);
        LOG.info("JVM Max Heap Size: " + this.maxHeapSize);
    }

    public static long getMaxHeapSize() {
        return getMaxHeapSize(ManagementFactory.getMemoryMXBean());
    }

    private static long getMaxHeapSize(MemoryMXBean bean) {
        long maxHeapSize = bean.getHeapMemoryUsage().getMax();
        /*
         * According to the javadoc, getMax() can return -1. In this case
         * default to 200MB. This will probably never actually happen.
         */
        if (maxHeapSize == -1) {
            LOG.warn(
                    "MemoryMXBean.getHeapMemoryUsage().getMax() returned -1, " + "defaulting maxHeapSize to 200MB");
            return 200L * 1024L * 1024L;
        }
        return maxHeapSize;
    }

    /**
     * Throws MapJoinMemoryExhaustionException when the JVM has consumed the
     * configured percentage of memory. The arguments are used simply for the error
     * message.
     *
     * @param tableContainerSize currently table container size
     * @param numRows number of rows processed
     * @throws MapJoinMemoryExhaustionException
     */
    public void checkMemoryStatus(long tableContainerSize, long numRows) throws MapJoinMemoryExhaustionException {
        long usedMemory = memoryMXBean.getHeapMemoryUsage().getUsed();
        double percentage = (double) usedMemory / (double) maxHeapSize;
        String msg = Utilities.now() + "\tProcessing rows:\t" + numRows + "\tHashtable size:\t" + tableContainerSize
                + "\tMemory usage:\t" + usedMemory + "\tpercentage:\t" + percentageNumberFormat.format(percentage);
        console.printInfo(msg);
        if (percentage > maxMemoryUsage) {
            throw new MapJoinMemoryExhaustionException(msg);
        }
    }
}