We are having thousands of mysql databases (v 5.7) and want to upgrade to latest v8.0. We have configured new mysql on same sarver with diff port (say 3307). we tried multiple steps
Replacing mysql5.7/data directory to mysql8.0/data gives an error on service start (attached error.log from mysql)
2019-08-08T10:44:03.134490-00:00 1 [System] [MY-011012] [Server] Starting upgrade of data directory.
2019-08-08T10:46:14.363244-00:00 1 [ERROR] [MY-012083] [InnoDB] Table mysql/plugin is not found in InnoDB dictionary
We checked mysql/plugin table on older version, table is listed in "show tables" command but gives an error on executing "desc plugin" as table not found.
- on new mysql 8.0 we started the service, stopped it again. Moved only databases folder mysql5.7/data directory to mysql8.0/data. but service couldn't started at this time.
Can some one guide me to upgrade thousands of dbs (volume 300+gb) to latest version in one go.. export/ import will take more time. Is there any alternate way?