In the MySQL team, we are considering deprecating the
mysqlhotcopy utility. To provide some background, here is an excerpt from the MySQL manual:
mysqlhotcopy is a Perl script that was originally written and contributed by Tim Bunce. It uses FLUSH TABLES, LOCK TABLES, and cp or scp to make a database backup. It is a fast way to make a backup of the database or single tables, but it can be run only on the same machine where the database directories are located. mysqlhotcopy works only for backing up MyISAM and ARCHIVE tables. It runs on Unix.
And now let me explain the motivations leading to our proposal:
- The name implies that this utility will work for ‘MySQL’ and is hot, but actually neither are true:
- Only MyISAM and ARCHIVE engines are supported.
- Tables are read-locked before the copy phase.
By contrast, backing up InnoDB tables with
mysqldump --single-transactionor MySQL Enterprise Backup uses the more traditional definition of ‘hot’, and allows both READ and WRITE operations to continue during the backup.
- There is no warning when backing up InnoDB tables that this operation is not supported. The .ibd files are also copied as part of creating the backup, which may mislead a user to believe they have successfully taken a backup.
- The manual page for mysqlhotcopy notes that the utility ‘runs on UNIX’, since it relies on some filesystem locking semantics which can not be guaranteed to work cross-platform. We would like to ensure that Windows users always have a first-class experience.
- mysqlhotcopy does not guarantee a consistent backup in the case that there are VIEWs present. I have a test-case available here to demonstrate.
Our current plan is to deprecate mysqlhotcopy in MySQL 5.6, with removal as early as MySQL 5.7. Do you use mysqlhotcopy? Will you be affected by the removal of this program?
We are seeking feedback from users who will be affected by this plan. Please leave a comment or get in touch!