又没录上，只能凭零星记忆来记录了

• 知识图谱有了解吗，知道用在你们系统哪个环节吗
• tomcat内存设置的多大。32位系统的话有限制吗？复盘：后面一想，可能是说32位系统地址寻址空间有限，内存最多4G
• gprc你们用的序列化方式？A：protobuf。Q：网络通信协议是HTTP还是TCP。复盘：HTTP2
• 如何处理kafka的重复消息
• elasticSearch集群搭建的情况。index是定时刷新还是实时刷新的？
  我参考了一些文档^{1 2} ，包括elastic的官网³：

Sitting between Elasticsearch and the disk is the filesystem cache. Documents in the in-memory indexing buffer (Figure 1) are written to a new segment (Figure 2). The new segment is written to the filesystem cache first (which is cheap) and only later is it flushed to disk(which is expensive). However, after a file is in the cache, it can be opened and read just like any other file.

In Elasticsearch, this process of writing and opening a new segment is called a refresh … You can control refreshes through the following means: … Waiting for the refresh interval …

By default, Elasticsearch periodically refreshes indices every second … This is why we say that Elasticsearch has near real-time search

给出了自己的简单概括（这个也可以回答2021年面试乐言时为什么es是近实时的提问）：
ES写入数据是先把数据写进内存，再写入 filesystem cache，最后再写入硬盘。在第二步（写入filesystem cache形成新的segment，这一步也被称为refresh）后，新数据就可以被搜索到了。refresh默认一秒执行一次（其实官网原文还有个条件，就是过去30秒有收到查询请求的index）。