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Migrating Using a Logical Dump and Replication

To minimize downtime during migration, you can set up live replication from your source database to the SkySQL database.

Prerequisites

  1. An active SkySQL account. Identify requirements for your SkySQL implementation prior to deployment, including:
  2. Topology - Enterprise Server Single node or with Replica(s)
  3. Instance size
  4. Storage requirements
  5. Desired server version
  6. An existing source database with the IP added to your SkySQL allowlist.

Steps

  1. Dump the Source Database: Take a dump of your source database using mysqldump or mariadb-dump. Include triggers, procedures, views, and schedules in the dump, and ignore the system databases to avoid conflicts with the existing SkySQL schemas.

    mysqldump --single-transaction --master-data=2 --routines --triggers --ignore-database=mysql --ignore-database=information_schema --ignore-database=performance_schema --ignore-database=sys > dump.sql

  2. Create the Users and Grants Separately: To avoid conflicts with the existing SkySQL users, use SELECT CONCAT on your source database to create users and grants in separate files. Note that you may need to create the schema and table grants separately as well.

    mysql -u [username] -p -h [hostname] --silent --skip-column-names -e "SELECT CONCAT('CREATE USER \'', user, '\'@\'', host, '\' IDENTIFIED BY PASSWORD \'', authentication_string, '\';') FROM mysql.user;" > users.sql

mysql -h [hostname] -u [username] -p --silent --skip-column-names -e "SELECT CONCAT('GRANT ', privilege_type, ' ON ', table_schema, '.* TO \'', grantee, '\';') FROM information_schema.schema_privileges;" > grants.sql

mysql -h [hostname] -u [username] -p --silent --skip-column-names -e "SELECT CONCAT('GRANT ', privilege_type, ' ON ', table_schema, '.', table_name, ' TO \'', grantee, '\';') FROM information_schema.table_privileges;" >> grants.sql

  3. Import the Dumps into SkySQL: Import the logical dumps (SQL files) into your SkySQL database, ensuring to load the user and grant dumps after the main dump.

    mariadb -u [SkySQL username] -p -h [SkySQL hostname] --port 3306 --ssl-verify-server-cert < dump.sql
mariadb -u [SkySQL username] -p -h [SkySQL hostname] --port 3306 --ssl-verify-server-cert < users.sql
mariadb -u [SkySQL username] -p -h [SkySQL hostname] --port 3306 --ssl-verify-server-cert < grants.sql

If you encounter an error while importing your users, you may need to uninstall the simple_password_check plugin on your SkySQL instance.

```sql
UNINSTALL PLUGIN simple_password_check;
```

  1. Start Replication: Turn on replication using SkySQL stored procedures. There are procedures allowing you to set and start replication. See our documentation for details. The dump.sql file you created in step 1 will contain the GTID and binary log information needed for the change_external_primary procedure.

    ```sql CALL sky.change_external_primary( host VARCHAR(255), port INT, logfile TEXT, logpos LONG , use_ssl_encryption BOOLEAN );

    CALL sky.replication_grants(); CALL sky.start_replication(); ```

Performance Optimization During Migration

  • Disable Foreign Key Checks: Temporarily disable foreign key checks during import to speed up the process.

    SET foreign_key_checks = 0;

  • Disable Binary Logging: If binary logging is not required during the import process, and you are using a standalone instance, it can potentially be disabled to improve performance. SkyDBA Services can assist with this as part of a detailed migration plan.

Data Integrity and Validation

  • Consistency Checks: Perform consistency checks on the source database before migration. Use a supported SQL client to connect to your SkySQL instance and run the following.

    CHECK TABLE [table_name] FOR UPGRADE;

  • Post-Import Validation: Validate the data integrity and consistency after the import.

    CHECKSUM TABLE [table_name];

Advanced Migration Techniques

  • Adjust Buffer Sizes: Temporarily increase buffer sizes to optimize the import performance. This can be done via the Configuration Manager in the portal.

    innodb_buffer_pool_size = 2G
innodb_log_file_size = 512M

  • Parallel Dump and Import: Use tools that support parallel processing for dumping and importing data.

    mysqldump -u [username] -p --default-parallelism=4 --add-drop-database \
    --databases [database_name] > dump.sql

  • Incremental Backups: For large datasets, incremental backups can be used to minimize the amount of data to be transferred. SkyDBA Services can assist you with setting these up as part of a custom migration plan.

Monitoring and Logging

  • Enable Detailed Logging: Enable detailed logging while testing the migration process to monitor and troubleshoot effectively. The slow_log can be enabled in the SkySQL configuration manager.

  • Resource Monitoring: Use monitoring tools to track resource usage (CPU, memory, I/O) during the migration to ensure system stability. See our monitoring documentation for details.

Additional Resources