What is the concept of TiDB instances? How should I connect to it?

[sykp241095]

原帖作者：Candice\n原帖时间：2022-12-16 09:48:41.349188\n原帖ID/Slug：109 / what-is-the-concept-of-tidb-instances-how-should-i-connect-to-it\n\n

Note that this question was originally posted on the Chinese TiDB Forum. We copied it here to help new users solve their problems quickly.

Application environment:

Test environment

TiDB version:

TiDB v6.0.0

Problem:

I started two TiDB servers and three TiKV servers. The data read from both TiDB servers is the same. Do I need to connect two TiDB servers and then do load balancing? Which TiDB server should I connect to in the application layer?

[sykp241095]

原帖作者：Mia\n原帖时间：2022-12-16 09:51:02.932577\n\n

TiDB Server is stateless, connecting to any of them is possible. For your reference, you can read this doc about TiDB architecture:TiDB Architecture | PingCAP Docs

You can also do load balancing to achieve high availability. Haproxy, F5, SLB/CLB, Weir, etc. can be used as load balance middleware. Here is a doc about the best practices for using HAProxy in TiDB： Best Practices for Using HAProxy in TiDB | PingCAP Docs