我写了一个服务调用elasticsearch做增删改查的，结果前些天有一起假死事件，现象是服务全都没流量了，请求进不来，rpc服务队列里面堆积了好多请求都超时了。过了十几分钟后这个现象自己就缓解了。

当时的GC频率不高都是年轻带GC，qps也属于正常的范围，日志记录的耗时较长的查询或修改 但是我再拿去执行的时候发现其实耗时并不长，也许是因为请求超时了所以才会统计到耗时较长吧，感觉这个线索不具备可靠性。

还有一种可能，就是服务层和es集群的连接数满了，导致那一会儿请求es集群的任务都阻塞了？我的客户端是这么写的：

public class ClientManager {

private static Logger logger = LogManager.getLogger(ClientManager.class.getName());

private static final String CLUSTER_NAME = "cluster.name";
private static final String ES_SERVICES = "es.services";

private Client client;

private static class ClientManagerHolder {
    private ClientManagerHolder() {
    }

    private static final ClientManager INSTANCE = new ClientManager();
}

public static Client getClient() {
    return ClientManagerHolder.INSTANCE.client;
}

private ClientManager() {
    if (client == null) {
        createClient();
    }
}

private void createClient() {
    // init

    String configPath = Path.getCurrentPath() + "/../config/app.properties";
    logger.info("######## appConfig配置文件路径  " + configPath);
    AppConfig.init(configPath);

    try {
        String clusterName = AppConfig.getProperty(CLUSTER_NAME);
        String services = AppConfig.getProperty(ES_SERVICES);
        logger.debug("es.services:" + services);
        logger.debug("clusterName:" + clusterName);
        Settings settings = Settings.settingsBuilder().put("cluster.name", clusterName)
                .put("client.transport.sniff", true).put("client.transport.ignore_cluster_name", true)
                .put("client.transport.ping_timeout", "1s").put("client.transport.nodes_sampler_interval", "1s")
                .build();
        // add delete-by-query plugin
        TransportClient c = TransportClient.builder().settings(settings).addPlugin(DeleteByQueryPlugin.class)
                .build();
        String[] servicesArray;
        if (StringUtils.isNotBlank(services)) {
            servicesArray = services.split(",");
            for (String service : servicesArray) {
                String[] serviceInfo = service.split(":");
                if (serviceInfo.length > 1) {
                    c = c.addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName(serviceInfo[0]),
                            Integer.valueOf(serviceInfo[1])));
                }
            }
            client = c;
            logger.info("connect to es cluster success.");
        } else {
            logger.error(" has no services info.");
        }

    } catch (Exception e) {
        logger.error("create es client failed.", e);
    }
}

}
大致就是做了个单例，但是我不太清楚esclient 有没有做连接池 或者请求关闭等操作？总之我是没有手动调用过close方法的，不知道是不是这块导致连接池资源都释放不掉了。

es有关连接池部分的配置我也发一下吧：
threadpool:

    index:
            type: fixed
            size: 24
            queue_size: 500
    bulk:
            type: fixed
            size: 24
            queue_size: 500

action.write_consistency: one
index.store.type: mmapfs
indices.memory.index_buffer_size: 10%
index.translog.flush_threshold_ops: 50000
index.translog.flush_threshold_size: 500mb
index.translog.flush_threshold_period: 10m
indices.memory.min_translog_buffer_size: 512m
indices.memory.max_translog_buffer_size: 512m
indices.queries.cache.size: 512m
indices.queries.cache.count: 5000

求大神帮忙分析