MySQL master-slave synchronization - how to transfer existing data from the master database to the slave database

1. Copy the data from the master database to the slave database

This step is mainly for the master database that has been running for a period of time. Historical data needs to be imported into the slave database to ensure strong master-slave consistency.

Main database lock table stops writing operations

Execute in the main database MySQL command line

flush tables with read lock;

Export main database data

Use the mysqldump command on the command line of the host where the main library is located to export all data.

mysqldump -uroot -p --all-databases|gzip > all_db.sql.gz

Import data into slave library

Transfer the exported file to the host where the slave library is located, and execute the import. Be careful not to make a mistake in the file path

mysqldump -uroot -p --all-databases < all_db.sql

 2. Configure master-slave synchronization

See the article for details:

MySQL master-slave synchronization (without GTID)_DK_521's blog-CSDN blog

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Problems you may encounter:

1. Mysqldump gets stuck there and doesn’t move. What should I do?

 solve:

When using mysqldumpbackup, add a parameter: --single-transaction, so that the data table can not be locked when backing up the database.

For example:

mysqldump -uroot -p --all-databases --single-transaction |gzip > all_db.sql.gz

Shoulders of Giants:

When mysqldump backed up, all data tables were locked and services could not be provided_mysqldump lock table_Heartsuit's blog-CSDN blog

The main database already has data configured for MySQL8 master-slave synchronization.