Any ideas on how to parallelize mysql_upgrade? I am migrating from 5.5 to 5.6 and would like to speed up the mysql_upgrade process. I have thousands of databases per machine and 200 tables (innodb) per db. Any suggestion how to speed up the upgrade process?
I upvoted your question because this is a common problem, and a solution would be welcome. But unfortunately, I believe that there is no way to parellalize it. mysql_upgrade always operates on the whole server directory, there is no way to only upgrade one database, and it reads the system tables.