Daniel Qian chanjarster

注：本文基于Elasticsearch 6.1.2编写

最近遇到这样一个需求，要通过Elasticsearch将Doc根据A字段降序，然后获得B字段的值，最终根据B字段的值再去做[Pipeline Aggregation][1]。

先尝试了[Max Aggregation][2]，但是Max Aggregation只能获得A字段的最大值。

然后尝试了[Top Hits Aggregation][3]，但是Top Hits Aggregation的结果无法被Pipeline Aggregation使用。

最终尝试[Scripted Metric Aggregation][4]成功。下面举例说明

	#!/bin/bash
	if [[ -z $1 \|\| -z $2 \|\| -z $3 \|\| -z $4 \|\| -z $5 \|\| -z $6 ]]; then
	echo 'usage: import-dpdump.sh <dba> <dba password> <user> <user password> <directory> <dump>'
	echo 'example: import-dpdump.sh admin 123456 user 123456 dir_object user20141010.dpdmp'
	exit
	fi

	dba=$1
	dbapsswd=$2
	user=$3

	/*
	Examples:

	查询我引用谁
	SELECT * FROM TABLE(FK_UTIL.get_refering_stats('TABLE_A'));

	查询谁引用我
	SELECT * FROM TABLE(FK_UTIL.get_refered_stats('TABLE_A'));

	查询ID为的某条记录的被引用计数

	import org.apache.catalina.Context;
	import org.apache.catalina.LifecycleException;
	import org.apache.catalina.session.StandardManager;
	import org.apache.catalina.startup.Tomcat;

	import javax.servlet.ServletException;
	import javax.servlet.http.HttpServlet;
	import javax.servlet.http.HttpServletRequest;
	import javax.servlet.http.HttpServletResponse;
	import javax.servlet.http.HttpSession;

	import java.text.ParseException;
	import java.text.SimpleDateFormat;
	import java.util.Date;

	/**
	* 中国居民身份证parser，支持15位，18位身份证
	* http://www.360doc.com/content/11/0322/21/4240950_103674335.shtml
	* http://baike.baidu.com/view/3457576.htm
	* Created by qianjia on 15/7/22.
	*/

	input {
	file {
	path => "/path/to/tomcat/logs/localhost_access_log*.txt"
	}
	}

	filter {
	grok {
	match => {
	"message" => "%{COMBINEDAPACHELOG} %{IPORHOST:serverip} %{NUMBER:serverport} %{NUMBER:elapsed_millis} %{NOTSPACE:sessionid} %{QS:proxiedip} %{QS:loginame}"

	http {
	// ssl 相关配置 ...

	map $http_upgrade $connection_upgrade {
	default upgrade;
	'' close;
	}

	server {
	listen 8020;

	# Haproxy的常见配置
	# 参考文档：
	# http://cbonte.github.io/haproxy-dconv/1.9/configuration.html
	# http://blog.sina.com.cn/s/blog_704836f40102w243.html
	# http://thread.gmane.org/gmane.comp.web.haproxy/12557
	# https://serverfault.com/questions/678882/is-there-a-way-to-rate-limit-connections-with-haproxy-using-
	# https://blog.codecentric.de/en/2014/12/haproxy-http-header-rate-limiting/
	# http://cbonte.github.io/haproxy-dconv/1.9/management.html
	# https://www.haproxy.com/blog/websockets-load-balancing-with-haproxy/