mariadb-backup and BACKUP STAGE

Understand backup locking stages. This page explains how mariadb-backup uses BACKUP STAGE statements to minimize locking during operation.

mariadb-backup was previously called mariabackup.

The BACKUP STAGE statements make it possible to make an efficient external backup tool. How mariadb-backup uses these statements depends on the version of MariaDB Server it is bundled with.

Every release of MariaDB Enterprise Server uses all of the BACKUP STAGE statements to do the work described below. MariaDB Community Server gained the same behavior in MariaDB Community Server 10.11.8, 11.0.6, 11.1.5, 11.2.4, and 11.4.2, and in every release since. See MDEV-32932.

The change landed in a maintenance release of each series, so the version series alone does not tell you which behavior you get. Releases before those listed above use the older behavior, as does every release in the 11.3 series.

For a complete list of mariadb-backup options, see this page.

For a detailed description of mariadb-backup functionality, see this page.

BACKUP STAGE in MariaDB Enterprise Server and MariaDB Community Server 10.11.8 and Later

The following sections describe how mariadb-backup uses each BACKUP STAGE statement in an efficient way.

BACKUP STAGE START

mariadb-backup performs the following tasks in the START stage:

• Copy all transactional tables.

  • InnoDB (i.e. ibdataN and file extensions .ibd and .isl)

  • Aria (i.e. aria_log_control and file extensions .MAD and .MAI)

• Copy the tail of all transaction logs.

  • The tail of the InnoDB redo log (i.e. ib_logfileN files) are copied for InnoDB tables.

  • The tail of the Aria redo log (i.e. aria_log.N files) are copied for Aria tables.

BACKUP STAGE FLUSH

mariadb-backup performs the following tasks in the FLUSH stage:

• Copy all non-transactional tables that are not in use. This list of used tables is found with SHOW OPEN TABLES.

  • MyISAM (i.e. file extensions .MYD and .MYI)

  • MERGE (i.e. file extensions .MRG)

  • ARCHIVE (i.e. file extensions .ARM and .ARZ)

  • CSV (i.e. file extensions .CSM and .CSV)

• Copy the tail of all transaction logs.

  • The tail of the InnoDB redo log (i.e. ib_logfileN files) are copied for InnoDB tables.

  • The tail of the Aria redo log (i.e. aria_log.N files) are copied for Aria tables.

BACKUP STAGE BLOCK_DDL

mariadb-backup performs the following tasks in the BLOCK_DDL stage:

• Copy other files.

  • i.e. file extensions .frm, .isl, .TRG, .TRN, .opt, .par

• Copy the non-transactional tables that were in use during BACKUP STAGE FLUSH.

  • MyISAM (i.e. file extensions .MYD and .MYI)

  • MERGE (i.e. file extensions .MRG)

  • ARCHIVE (i.e. file extensions .ARM and .ARZ)

  • CSV (i.e. file extensions .CSM and .CSV)

• Check ddl.log for DDL executed before the BLOCK DDL stage.

  • The file names of newly created tables can be read from ddl.log.

  • The file names of dropped tables can also be read from ddl.log.

  • The file names of renamed tables can also be read from ddl.log, so the files can be renamed instead of re-copying them.

• Copy changes to system log tables.

  • mysql.general_log

  • mysql.slow_log

  • This is easy as these are append only.

• Copy the tail of all transaction logs.

  • The tail of the InnoDB redo log (i.e. ib_logfileN files) are copied for InnoDB tables.

  • The tail of the Aria redo log (i.e. aria_log.N files) are copied for Aria tables.

BACKUP STAGE BLOCK_COMMIT

mariadb-backup performs the following tasks in the BLOCK_COMMIT stage:

• Create a MyRocks checkpoint using the rocksdb_create_checkpoint system variable.

• Copy changes to system log tables.

  • mysql.general_log

  • mysql.slow_log

  • This is easy as these are append only.

• Copy changes to statistics tables.

  • mysql.table_stats

  • mysql.column_stats

  • mysql.index_stats

• Copy the tail of all transaction logs.

  • The tail of the InnoDB redo log (i.e. ib_logfileN files) are copied for InnoDB tables.

  • The tail of the Aria redo log (i.e. aria_log.N files) are copied for Aria tables.

• Save the binary log position to xtrabackup_binlog_info.

• Save the Galera Cluster state information to xtrabackup_galera_info.

BACKUP STAGE END

mariadb-backup performs the following tasks in the END stage:

• Copy the MyRocks checkpoint into the backup.

BACKUP STAGE Before MariaDB Community Server 10.11.8

In these releases, the BACKUP STAGE statements are supported, but mariadb-backup does not use them in the most efficient way. It simply executes the following BACKUP STAGE statements to lock the database:

BACKUP STAGE START;
BACKUP STAGE BLOCK_COMMIT;

When the backup is complete, it executes the following BACKUP STAGE statement to unlock the database:

BACKUP STAGE END;

To use a version of mariadb-backup that uses the BACKUP STAGE statements in the most efficient way, upgrade to MariaDB Community Server 10.11.8, 11.0.6, 11.1.5, 11.2.4, or 11.4.2 or later, or use MariaDB Enterprise Server.

Tasks Performed Prior to BACKUP STAGE

• Copy some transactional tables.

  • InnoDB (i.e. ibdataN and file extensions .ibd and .isl)

• Copy the tail of some transaction logs.

  • The tail of the InnoDB redo log (i.e. ib_logfileN files) are copied for InnoDB tables.

BACKUP STAGE START

mariadb-backup does not perform any tasks in the START stage.

BACKUP STAGE FLUSH

mariadb-backup does not perform any tasks in the FLUSH stage.

BACKUP STAGE BLOCK_DDL

mariadb-backup does not perform any tasks in the BLOCK_DDL stage.

BACKUP STAGE BLOCK_COMMIT

mariadb-backup performs the following tasks in the BLOCK_COMMIT stage:

• Copy other files.

  • i.e. file extensions .frm, .isl, .TRG, .TRN, .opt, .par

• Copy some transactional tables.

  • Aria (i.e. aria_log_control and file extensions .MAD and .MAI)

• Copy the non-transactional tables.

  • MyISAM (i.e. file extensions .MYD and .MYI)

  • MERGE (i.e. file extensions .MRG)

  • ARCHIVE (i.e. file extensions .ARM and .ARZ)

  • CSV (i.e. file extensions .CSM and .CSV)

• Create a MyRocks checkpoint using the rocksdb_create_checkpoint system variable.

• Copy the tail of some transaction logs.

  • The tail of the InnoDB redo log (i.e. ib_logfileN files) are copied for InnoDB tables.

• Save the binary log position to xtrabackup_binlog_info.

• Save the Galera Cluster state information to xtrabackup_galera_info.

BACKUP STAGE END

mariadb-backup performs the following tasks in the END stage:

• Copy the MyRocks checkpoint into the backup.

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