The mysqldump command is used in MySQL to create backups of databases. One of its options, --apply-slave-statements, was historically used to include SQL statements that would enable a slave server to replicate the data from the dump. However, as of MySQL 8.0.22, this option has been deprecated due to potential issues with consistency and correctness in replication setups.
Here are several examples of how mysqldump --apply-slave-statements was used previously:
Example 1: Dumping a database with slave replication statements:
mysqldump --apply-slave-statements dbname > dbname_dump.sql
Output: The dump file dbname_dump.sql would include additional SQL statements that set up the slave to replicate from the dump, such as CHANGE MASTER TO commands.
To verify if the mysqldump command executed correctly, you can check the contents of the dump file using:
grep "CHANGE MASTER TO" dbname_dump.sql
This command would search for the presence of replication setup statements in the dump file.
Example 2: Dumping all databases with slave statements:
mysqldump --all-databases --apply-slave-statements > alldatabases_dump.sql
Output: The file alldatabases_dump.sql would contain replication setup statements for each database dumped.
Verification can be done by inspecting the dump file for occurrences of CHANGE MASTER TO statements related to each database.
Example 3: Dumping and compressing with slave replication:
mysqldump --apply-slave-statements dbname | gzip > dbname_dump.sql.gz
Output: This command compresses the dump file dbname_dump.sql.gz while including replication setup statements.
To ensure successful execution, decompress the file and check for CHANGE MASTER TO commands using tools like zcat and grep.
Despite its utility, caution should be exercised with --apply-slave-statements due to its deprecation and the potential for replication inconsistencies in modern MySQL environments.
Read Also
Apply Replica Statements in mysqldump Output
Allowing Keywords as Column Names in mysqldump Output
Include Locks around INSERT Statements in mysqldump
Adding DROP TRIGGER Statements in mysqldump Output
Include DROP TABLE Statements in mysqldump Output
Discussion about this post