Migrate from MySQL SQL Files Using TiDB Lightning

This document describes how to migrate data from MySQL SQL files to TiDB using TiDB Lightning. For details on how to generate MySQL SQL files, refer to Mydumper or Dumpling.

The data migration process described in this document uses TiDB Lightning. The steps are as follows.

Step 1: Deploy TiDB Lightning

Before you start the migration, deploy TiDB Lightning.

Note:

• If you choose the Importer-backend to import data, you need to deploy tikv-importer along with TiDB Lightning. During the import process, the TiDB cluster cannot provide services. This mode imports data quickly, which is suitable for importing a large amount of data (above the TB level).
• If you choose the TiDB-backend, deploy TiDB Lightning only. The cluster can provide services normally during the import.
• For detailed differences between the two backend mode, see TiDB Lightning Backend.

Step 2: Configure data source of TiDB Lightning

This document takes the TiDB-backend as an example. Create the tidb-lightning.toml configuration file and add the following major configurations in the file:

1. Set the data-source-dir under [mydumper] to the path of the MySQL SQL file.

   [mydumper]
   # Data source directory
   data-source-dir = "/data/export"

   Note:

   If a corresponding schema already exists in the downstream, set no-schema=true to skip the creation of the schema.

2. Add the configuration of the target TiDB cluster.

   [tidb]
   # The target cluster information. Fill in one address of tidb-server.
   host = "172.16.31.1"
   port = 4000
   user = "root"
   password = ""

For other configurations, see TiDB Lightning Configuration.

Step 3: Run TiDB Lightning to import data

Run TiDB Lightning to start the import operation. If you start TiDB Lightning by using nohup directly in the command line, the program might exit because of the SIGHUP signal. Therefore, it is recommended to write nohup in a script. For example:

# !/bin/bash
nohup ./tidb-lightning -config tidb-lightning.toml > nohup.out &

When the import operation is started, view the progress by the following two ways:

• grep the keyword progress in logs, which is updated every 5 minutes by default.
• Access the monitoring dashboard. See Monitor TiDB Lightning for details.