[2017-06-14T21:06:39,330][ERROR][o.e.b.ElasticsearchUncaughtExceptionHandler] [xx.xx.xx.xx] fatal error in thread [elasticsearch[xx.xx.xx.xx][search][T#29]], exiting
java.lang.StackOverflowError
        at org.apache.lucene.util.automaton.Operations.isFinite(Operations.java:1053) ~[lucene-core-6.2.1.jar:6.2.1 43ab70147eb494324a1410f7a9f16a896a59bc6f - shalin - 2016-09-15 05:15:20]
        at org.apache.lucene.util.automaton.Operations.isFinite(Operations.java:1053) ~[lucene-core-6.2.1.jar:6.2.1 43ab70147eb494324a1410f7a9f16a896a59bc6f - shalin - 2016-09-15 05:15:20]
        at org.apache.lucene.util.automaton.Operations.isFinite(Operations.java:1053) ~[lucene-core-6.2.1.jar:6.2.1 43ab70147eb494324a1410f7a9f16a896a59bc6f - shalin - 2016-09-15 05:15:20]
        at org.apache.lucene.util.automaton.Operations.isFinite(Operations.java:1053) ~[lucene-core-6.2.1.jar:6.2.1 43ab70147eb494324a1410f7a9f16a896a59bc6f - shalin - 2016-09-15 05:15:20]

POST /test/_search

{

  "query": {

    "regexp": {

      "test": "t{1,9500}"

    }

  }

}

public class PrefixQuery extends AutomatonQuery {



  /** Constructs a query for terms starting with <code>prefix</code>. */

  public PrefixQuery(Term prefix) {

    // It's OK to pass unlimited maxDeterminizedStates: the automaton is born small and determinized:

    super(prefix, toAutomaton(prefix.bytes()), Integer.MAX_VALUE, true);

    if (prefix == null) {

      throw new NullPointerException("prefix must not be null");

    }

  // TODO: not great that this is recursive... in theory a

  // large automata could exceed java's stack

  private static boolean isFinite(Transition scratch, Automaton a, int state, BitSet path, BitSet visited) {

    path.set(state);

    int numTransitions = a.initTransition(state, scratch);

    for(int t=0;t<numTransitions;t++) {

      a.getTransition(state, t, scratch);

      if (path.get(scratch.dest) || (!visited.get(scratch.dest) && !isFinite(scratch, a, scratch.dest, path, visited))) {

        return false;

      }

    }

    path.clear(state);

    visited.set(state);

    return true;

  }

ElasticHD 是一款 ElasticSearch的可视化应用。不依赖ES的插件安装，更便捷；导航栏直接填写对应的ES IP和端口就可以操作Es了。目前支持如下功能：

•  ES Real time data search
•  ES Dashboard data visualization
•  ES Index Template (在线修改、查看、上传）
•  ES Indices Index deletion and search
•  SQL Converts to Elasticsearch DSL
•  ES 基本查询文档

•   linux and MacOs use ElasticHD

1. 下载对应的elasticHD版本，unzip xxx_elasticHd_xxx.zip 
2. 修改权限 chmod 0777 ElasticHD 
3. 可指定ip端口运行elastichd ./ElasticHD -p 127.0.0.1:9800 默认 ip和端口也是这个

•  windows use ElasticHD 
• 直接下载对应windows版本,解压，双击运行。当然想指定端口的话同linux

1. 修复 bug，单分片进行 scroll 操作可能引起 X-Pack Security 造成节点僵死及 OOM。
2. Elasticsearch 5.4.0 启用 TLS 不能对 5.3.x 和之前的节点进行认证。
3. LDAP 认证用户在撤销认证之后后可能任然驻留在缓存。
4. 现在，Netty在处理线程池、缓冲池和其他资源时，尊重处理器的设置，而不是在其他容器上运行时，可能会对这些资源进行过度的调整。
5. 对关闭的索引进行 Index setting 修改将进行验证，保护因为错误的配置造成索引无法打开的问题。
6. 修复 TransportClient 关于嗅探可能造成客户端挂起的异常。
7. 修复在KERBEROS安全模式，HDFS repository 插件与 Java Security Manager 发生的冲突。
8. 修复 Snapshot/restore 在 Elasticsearch 5.2.x 及之前的版本在取回所有快照时异常缓慢的问题。

• Debugging Java Native Memory Leaks
• Tracking Down Native Memory Leaks in Elasticsearch
• CompressingStoredFieldsFormat should reclaim memory more aggressively
• Close InputStream when receiving cluster state in PublishClusterStateAction
• Kafka OOM During Log Recovery Due to Leaked Native Memory