Guide to Upgrading MySQL from 5.7 to 8.0

MySQL 8.0 offers improved security, performance, stability, and new features such as hash joins, window functions, instant DDL, and enhanced JSON support, making it a compelling upgrade target for DBAs.

Before upgrading, administrators should verify dictionary upgrades (e.g., password authentication changes), keyword and SQL compatibility, storage engine formats, application compatibility, and password policies.

Key new features and deprecated/removed items are listed in the official MySQL documentation, and the upgrade process can be assisted by MySQL Shell utilities.

Preparation steps include testing upgrades in a sandbox, backing up data, adjusting my.cnf, identifying incompatible operations, planning a phased rollout (e.g., upgrading a replica first), estimating downtime, and defining rollback procedures.

Pre‑upgrade checks can be performed with MySQL Shell, for example:

#mysqlsh root:[email protected]:3410 -e 'util.checkForServerUpgrade({"targetVersion":"8.0.19","configPath":"/etc/my3410.cnf"})';

During the upgrade, the mysql_upgrade client is deprecated; the server now handles necessary upgrades when started with the new binaries. Ensure a clean shutdown by setting innodb_fast_shutdown=0, then back up the data.

Start the new MySQL 8.0 server:

[root@ss30 bin]# /opt/mysql8.0.19/bin/mysqld_safe --defaults-file=/etc/my3400.cnf --user=mysql &

Verify the server is running and check the version:

mysql> select version();
+-----------+
| version() |
+-----------+
| 8.0.19    |
+-----------+

Confirm no MyISAM tables remain and that all engines are InnoDB. After verification, perform application testing to ensure normal operation.

The article concludes that a successful upgrade requires thorough planning, testing, backup, and validation, after which teams can begin leveraging MySQL 8.0’s new capabilities.