1.coding, LRU。2.http请求头和响应头的结构?3.常见http响应码? 502和504的区别?4.mysql innodb的索引结构?5. 以下情况的索引使用情况:create table myTest (a string, b int, c int, KEY a(a,b,c));(1).select * from myTest where c=3 and a="test" and b=5;(2).select * from myTest where a="test" and b>5 and c=6;(3).select * from myTest where a="test" order by b asc;(4).select * from myTest order by a asc, b desc;(5).select a,b,c from myTest where a like "te%" and b=5 and c=3;6. 某高并发电商系统,订单表日增量超过500万条,当前单表数据量已达数十亿,导致慢查询频发,分页查询深度偏移时性能急剧下降。如何优化?7. 聊项目。