Question

我正在考虑添加JMX bean以获取lucene索引的热备份。

LuceneMBean mbean = new LuceneMBeanImpl（）; ObjectName name = new ObjectName（“indexing.index：type = lucene”）; MBeanServer mbs = ManagementFactory.getPlatformMBeanServer（）; mbs.registerMBean（mbean，name）;

LuceneMBean将有一个名为backupIndex（String directory）的方法。

我已经浏览了lucene docs并找到了Directory的copy（）方法。如果我在目录上有Writer Open，这个方法会起作用吗？基本上我的代码片段如下：

public class LuceneMBeanImpl implements LuceneMBean{
     public void backupIndex(String directory){
           Directory fileDirectory =  FSDirectory.getDirectory(directory);
           Directory.copy(masterDirectory, fileDirectory,false);
     }
}

Answer 1

我认为一个开放的Writer应该没问题，但是当另一个线程正在修改索引时你肯定无法复制，或者你可能会得到一个FileNotFoundException。来自消息来源：

 /**
   * Copy contents of a directory src to a directory dest.
   * If a file in src already exists in dest then the
   * one in dest will be blindly overwritten.
   *
   * <p><b>NOTE:</b> the source directory cannot change
   * while this method is running.  Otherwise the results
   * are undefined and you could easily hit a
   * FileNotFoundException.
   *
   * @param src source directory
   * @param dest destination directory
   * @param closeDirSrc if <code>true</code>, call {@link #close()} method on source directory
   * @throws IOException
   */
  public static void copy(Directory src, Directory dest, boolean closeDirSrc) throws IOException {

如何采取lucene FileDirecotry索引的在线热备份？

1 个答案: