# Modules in TiDB Server

__*TiDB Server Modules*__

![left](./student-guide/diagram/TiDBServerComponentsSimple_en_002_20220514.png)

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When TiDB Server is expanded, the user's SQL request will be sent directly or through the Load Balancer to the TiDB Server. The TiDB Server will parse the MySQL Protocol Packet, obtain the request content, perform syntax parse and semantic analysis on the SQL, develop and optimize Query plans, execute query plans, and obtain and process data. The data is all stored in the TiKV cluster, so in this process, the TiDB Server needs to interact with TiKV to get the data. Finally, TiDB Server needs to return the query results to the user.