loadertool to export and import all the data
You can use
mydumper to export data from MySQL and
loader to import the data into TiDB.
Although TiDB also supports the official
mysqldumptool from MySQL for data migration, it is not recommended to use it. Its performance is much lower than
loaderand it takes much time to migrate large amounts of data. It is important to use the
mydumperprovided by TiDB and not the upstream
mydumperversion. See Mydumper for more information.
loader can be downloaded as part of Enterprise Tools.
mydumper tool to export data from MySQL by using the following command:
./bin/mydumper -h 127.0.0.1 -P 3306 -u root -t 16 -F 64 -B test -T t1,t2 --skip-tz-utc -o ./var/test
In this command,
-B test: means the data is exported from the
-T t1,t2: means only the
t2tables are exported.
-t 16: means 16 threads are used to export the data.
-F 64: means a table is partitioned into chunks and one chunk is 64MB.
--skip-tz-utc: the purpose of adding this parameter is to ignore the inconsistency of time zone setting between MySQL and the data exporting machine and to disable automatic conversion.
On the Cloud platforms which require the
super privilege, such as on the Amazon RDS, add the
--no-locksparameter to the command. If not, you might get the error message that you don’t have the privilege.
loader to import the data from MySQL to TiDB. See Loader instructions for more information.
./bin/loader -h 127.0.0.1 -u root -P 4000 -t 32 -d ./var/test
After the data is imported, you can view the data in TiDB using the MySQL client:
mysql -h127.0.0.1 -P4000 -uroot mysql> show tables; +----------------+ | Tables_in_test | +----------------+ | t1 | | t2 | +----------------+ mysql> select * from t1; +----+------+ | id | age | +----+------+ | 1 | 1 | | 2 | 2 | | 3 | 3 | +----+------+ mysql> select * from t2; +----+------+ | id | name | +----+------+ | 1 | a | | 2 | b | | 3 | c | +----+------+
To migrate data quickly, especially for huge amount of data, you can refer to the following recommendations.
-Fparameter to set the value.
loaderbased on the number and the load of TiKV instances. For example, if there are three TiKV instances,
-tcan be set to 3 * (1 ~ n). If the load of TiKV is too high and the log
backoffer.maxSleep 15000ms is exceededis displayed many times, decrease the value of
-t; otherwise, increase it.
mydumperis set to 16 and the
loaderis set to 64.
Results: It takes 11 hours to import all the data, which is 19.4G/hour.