https://www.elastic.co/
https://www.elastic.co/guide/en/elasticsearch/reference/current/getting-started.html
https://www.elastic.co/guide/en/elasticsearch/reference/current/search-request-scroll.html
http://www.16php.com/archives/380
http://www.tuicool.com/articles/nyiMFv
http://www.cnblogs.com/luxiaoxun/p/4869509.html
http://www.tuicool.com/articles/uUNvMnJ
https://www.baidu.com/s?wd=mysql%20slow%20log&rsv_spt=1&rsv_iqid=0xaed28e630004268f&issp=1&f=8&rsv_bp=0&rsv_idx=2&ie=utf-8&tn=baiduhome_pg&rsv_enter=1&rsv_sug3=14&rsv_sug1=8&rsv_n=1&sug=mysql%20slow%20log
https://www.elastic.co/products/elasticsearch
http://www.cnblogs.com/yjf512/p/4865930.html
http://www.qixing318.com/article/the-concept-of-elasticsearch.html
https://www.zhihu.com/question/29360024/answer/55368070
http://www.cnblogs.com/vovlie/p/4227027.html