Downgrade MySQL
- In the unlikely case that the previous version worked better than the new one, a downgrade may be necessary.
- Back up the databases, including the
mysql database that contains the grant tables.
- It is always a good idea to make a backup.
- If there is a downgrading section to the release notes, read it.
- In most cases, one can move the MySQL format files and data files between different versions on the same architecture within versions for the same release series of MySQL.
- Downgrading from 5.1 to 5.0.
- If downgrading from one release series to another, there may be incompatibilities in table storage formats.
- In this case, use
mysqldump to dump the tables before downgrading.
- After downgrading, reload the dump file using
mysql or mysqlimport to re-create the tables.
- Being unable to open tables is the normal symptom of a downward-incompatible table format change.
- In that case, to solve the problem, use the following procedure:
- Stop the older MySQL server.
- Restart the newer MySQL server.
- Dump any tables that were inaccessible to the older server by using
mysqldump to create a dump file.
- Stop the newer MySQL server and restart the older one.
- Reload the dump file into the older server.
- The tables should be accessible.
What are the environment variables used by MySQL?
© 2007 John Michael Pierobon
Notes