What specific information is stored in the schema load of the TiDB Server?

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Original topic: TiDB Server中 schema load具体存储什么信息？

| username: alfred

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| username: forever | Original post link

The Online DDL operation in TiDB requires the collaboration of the start job, worker, and schema load modules on the TiDB Server nodes, as well as the job queue and history queue on the TiKV nodes.

In the TiDB database, only one TiDB Server can perform Online DDL operations at any given time. We refer to the TiDB Server that can execute Online DDL tasks at the current moment as the Owner.

The scheduling process for Online DDL operations in TiDB is roughly as follows:

  1. Different users connect to different TiDB Servers, and the DDL operations they issue are received by the start job module, which generates a corresponding job and places it in the job queue on the TiKV nodes.
  2. The worker module in the TiDB Server acting as the Owner will fetch the Online DDL job from the job queue on the TiKV nodes to execute. The executed job will be moved to the history queue, and then the Owner will fetch the next job from the job queue to execute.
  3. When the current Owner’s term ends, a new TiDB Server will be elected as the new Owner to execute Online DDL tasks. At the same time, the schema load module in the new Owner will synchronize the latest schema information of all tables to the cache of the TiDB Server.
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| username: Running | Original post link

The original poster is professional.

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| username: tidb菜鸟一只 | Original post link

This behavior would be called “necroposting” in forums, right?

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| username: system | Original post link

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