OpenHFT/历史记录映射失败

Question

我使用一个VanillaChroncile临时存储和检索条目，除了有巨大的负载外，它工作得非常好。我得到地图失败异常。虽然我有处理此异常的恢复逻辑，但我想知道为什么首先会出现此异常。任何帮助都将不胜感激。

     public enum PreAuthEventChronicle {
INSTANCE;
private String basePath = PropertyUtilsEnum.INSTANCE.getChronicleDirPath();
private final Logger logger = Logger.getLogger(PreAuthEventChronicle.class);
private long indexBlockSize = 64L;
// Length of the excerpt.
private final int excerptLength = 1024;
private final int cycleLength = "yyyyMMddhhmmss";
// Number of entries that are stored in the chronicle queue.
private final long entriesPerCycle = 1L << 20;
// Format for the folder. Chronicle writes in GMT time zone.
private final String format = ApplicationConstants.CHRONICLE_FORMAT;
private Chronicle chronicle = null;
private List<PreAuthEventListener> listeners = new      ArrayList<PreAuthEventListener>();

public Chronicle getChr() {
    return chronicle;
}

/**
 * There can only be one chronicle built.
 */
private PreAuthEventChronicle() {
    if (basePath != null) {
        if (!basePath.endsWith(ApplicationConstants.FILE_SEP)) {
            basePath = basePath + ApplicationConstants.FILE_SEP + ApplicationConstants.CHRONICLE_DATA_PATH;
        }
        logger.debug("Starting from a clean state");
        cleanUp();
        logger.debug("Building a Vanilla Chronicle instance with path: " + basePath);
        buildChronicle();
    } else {
        throw new RuntimeException("No directory specified for chronicle to be built.");
    }
}

private void buildChronicle() {
    logger.debug("Begin-Starting to build a vanilla chronicle");
    try {
        if (chronicle != null) {
            chronicle.clear();
            chronicle = null;
        }
        chronicle = ChronicleQueueBuilder.vanilla(basePath).cycleLength(cycleLength, false).cycleFormat(format)
                .indexBlockSize(indexBlockSize).entriesPerCycle(entriesPerCycle).build();
    } catch (IOException e) {
        logger.error("Error building chronicle" + e.getMessage());
    }
    logger.debug("End-Finished building the vanilla chronicle");
}

/**
 * Clean up the resources
 */
public void cleanUp() {
    logger.debug("Begin-Cleaning up chronicle resources");
    File f = new File(basePath);
    if (f.exists() && f.isDirectory()) {
        File[] dirs = f.listFiles();
        for (File dir : dirs) {
            if (dir.isDirectory()) {
                try {
                    FileUtils.deleteDirectory(dir);
                } catch (IOException ignore) {
                }
            }
        }
    }
    buildChronicle();
    logger.debug("End-Done cleaning up chronicle resources");
}

/**
 * Write the object to the chronicle queue, and notify the listeners
 * 
 * @param event
 * @throws IOException
 */
public synchronized void writeObject(Object event) throws IOException {
    ExcerptAppender appender = INSTANCE.getChr().createAppender();
    if (appender != null && event != null) {
        logger.debug("Begin-Writing event to the chronicle queue");
        appender.startExcerpt(excerptLength);
        appender.writeObject(event);
        appender.finish();
        appender.clear();
        appender.close();
        notifyListeners();
        logger.debug("End-Done writing event to the chronicle queue.");
    }
}

/**
 * Read the object from the queue
 * 
 * @return
 * @throws IOException
 */
public synchronized Object readObject() throws IOException {
    ExcerptTailer reader = INSTANCE.getChr().createTailer().toStart();
    Object evt = null;
    while (reader != null && reader.nextIndex()) {
        logger.debug("Begin-Reading event from the chronicle queue");
        evt = reader.readObject();
        reader.finish();
        reader.clear();
        reader.close();
        logger.debug("End-Done reading the event from the chronicle queue.");
    }
    return evt;
}

/**
 * Attach a listener
 * 
 * @param listen
 */
public void attachListener(PreAuthEventListener listen) {
    listeners.add(listen);
}

/**
 * Notify the listeners that an event has been written.
 */
private void notifyListeners() {
    for (PreAuthEventListener listener : listeners) {
        logger.debug("Notification received from the chronicle queue. Performing action.");
        listener.perform();
    }
}

}

Answer 1

了解您得到的异常情况会很有用，但我敢打赌原因是OutOfMemoryError。

关于您的代码：

• 你想要滚动每一秒，这是可能的，但不是真正有效的每个滚动，Chronicle-Queue需要mmap至少两个区域
• readObject/WriteObject是不需要的同步方法，因为Va nillaChronque是线程安全的
• 在readObject中，你关闭了每个循环中的尾轮，这可能会导致映射区域在每次迭代中被取消映射/映射，最好在循环之外调用关闭（）
• 在WriteObject中，你显式地关闭摘录，如果你不能控制调用该方法的线程数量，这是可以的，但这可能不是最有效的方法，因为每个新线程都必须映射一个新区域
• 不需要调用[ailer|appender]. Clear（）