Migrate from RDS for MySQL to RocketMQ-Data Transmission Service(DTS)-阿里云帮助中心

Prerequisites

You have created a target non-Serverless ApsaraMQ for RocketMQ instance. For more information, see Manage instances or Manage instances.

Note
For the supported versions of the source and target databases, see migration scenarios.
A topic is created in the target Alibaba Cloud Message Queue for RocketMQ instance to receive the data to be migrated. For more information about how to create a topic, see Manage topics or Manage topics.

Important
For 4.x series, the Message Type for the topic must be set to Partitionally Ordered Message.

For 5.x series, the Message Type for the topic must be set to Ordered Message.

Limitations

Type	Description
Source database limitations	Bandwidth requirement: The server hosting the source database must have sufficient outbound bandwidth. Otherwise, migration speed will drop. Migration objects: Each table to migrate must have a primary key or UNIQUE constraint, and the key columns must contain unique values. Otherwise, duplicate records may appear in the destination database. If you select tables as the migration objects and edit them—for example, by mapping column names—a single migration task supports up to 1,000 tables. If you exceed this limit, the task fails with an error when submitted. To fix this, split the tables across multiple tasks or configure a full-database migration task. If you need incremental migration, enable binary logging: Set binlog_format to ROW and binlog_row_image to FULL. Otherwise, the precheck fails and the task cannot start. Important If your self-managed MySQL source is a dual-master cluster—where each instance acts as both master and slave—enable the log_slave_updates parameter. This ensures DTS can read all binary logs. For RDS for MySQL instances, retain local binary logs for at least three days (seven days recommended). For self-managed MySQL databases, retain local binary logs for at least seven days. If DTS cannot access binary logs, the task fails. In extreme cases, data inconsistency or data loss may occur. Issues caused by binary log retention periods shorter than DTS requires are not covered under the DTS SLA. Note To set the retention period for local binary logs on an RDS for MySQL instance, see Automatically delete local logs. During the schema migration and full migration phases, do not perform DDL operations that change the database or table structure. Otherwise, the data migration task will fail. Note During the full migration phase, DTS queries the source database. This creates a metadata lock that may block DDL operations on the source database. If you perform only a full data migration, do not write new data to the source database. Otherwise, the data in the source and destination databases will become inconsistent. To maintain data consistency in real time, select both full data migration and incremental data migration. DTS does not migrate data generated by changes that do not write to binary logs. Examples include data restored from physical backups or created by cascade operations. Note If this occurs, re-run full migration after your business allows it. If your source MySQL database is version 8.0.23 or later and contains invisible hidden columns, DTS cannot read those columns. This may cause data loss. Note Run `ALTER TABLE <table_name> ALTER COLUMN <column_name> SET VISIBLE;` to make the hidden column visible. For more information, see Invisible Columns.
Other limitations	Serverless instances of ApsaraMQ for RocketMQ are not supported as the destination. You can migrate data only to specific topics in the destination ApsaraMQ for RocketMQ instance. For 4.x series instances, the message type of the destination topic must be partitionally ordered message. If the destination ApsaraMQ for RocketMQ instance and the source database are in different Instance Region, DTS accesses the destination ApsaraMQ for RocketMQ instance over the internet. This incurs internet traffic fees. Make sure that public access is enabled for the destination ApsaraMQ for RocketMQ instance. Note You can view the public access status on the Basic Information tab of the instance details page in the ApsaraMQ for RocketMQ console. For more information about the internet traffic fees for the destination ApsaraMQ for RocketMQ instance, see Internet traffic pricing details. For 5.x series instances, the message type of the destination topic must be ordered message. The destination ApsaraMQ for RocketMQ instance supports a maximum message body size of 4 MB. If the specifications of the destination ApsaraMQ for RocketMQ instance change (for example, when you upgrade or downgrade the instance), the delivery order of the DTS instance may differ from the order before the change. Messages are subsequently delivered based on the new order. During full data migration, DTS consumes read and write resources on the source and destination databases, which may increase the database load. Before you start data migration, evaluate the performance of the source and destination databases. Perform data migration during off-peak hours, for example, when the CPU utilization of both databases is below 30%. During full data migration, concurrent INSERT operations cause table fragmentation in the destination database. As a result, after the full data migration is complete, the storage space occupied by tables in the destination database may be larger than that in the source database. During data migration, do not use tools such as pt-online-schema-change to perform online DDL operations on the migration objects in the source database. Otherwise, the migration task fails. If another source writes data to the destination database during data migration, data inconsistency may occur between the source and destination databases. If the EncDB feature is enabled for an ApsaraDB RDS for MySQL instance, full data migration is not supported. Note An ApsaraDB RDS for MySQL instance with transparent data encryption (TDE) enabled supports both full data migration and incremental data migration. If a task fails, DTS support staff will attempt to restore it within eight hours. During restoration, they may restart the task or adjust its parameters. Note Only DTS task parameters are modified—not database parameters. Parameters that may be adjusted include those listed in Modify instance parameters.
Special cases	For self-managed MySQL sources: A master–standby switchover on the source database causes the migration task to fail. DTS calculates latency by comparing the timestamp of the last record migrated to the destination database with the current time. If no DML operations run on the source for a long time, latency reporting becomes inaccurate. If latency appears too high, run a DML operation on the source to update the latency value. Note If you select full-database migration, create a heartbeat table. Update or write to it every second. DTS periodically runs CREATE DATABASE IF NOT EXISTS `test` on the source database to advance the binary log offset. If your source is Amazon Aurora MySQL or another clustered MySQL instance, ensure the domain name or IP address configured for the task—and its DNS resolution—always points to a read–write (RW) node. Otherwise, the migration task may fail. For RDS for MySQL sources: If you need incremental migration, RDS for MySQL instances that do not record transaction logs—such as RDS for MySQL 5.6 read-only instances—are not supported as sources. DTS periodically runs CREATE DATABASE IF NOT EXISTS `test` on the source database to advance the binary log offset.

Billing

Migration type	Instance configuration fee
Full data migration	Free of charge.
Incremental data migration	Charged. For more information, see billing overview.

SQL operations for incremental migration

Operation type	SQL statement
DML	INSERT, UPDATE, and DELETE
DDL	CREATE TABLE, ALTER TABLE, DROP TABLE, RENAME TABLE, and TRUNCATE TABLE CREATE VIEW, ALTER VIEW, and DROP VIEW CREATE PROCEDURE, ALTER PROCEDURE, and DROP PROCEDURE CREATE FUNCTION, DROP FUNCTION, CREATE TRIGGER, and DROP TRIGGER CREATE INDEX and DROP INDEX

Database account permissions

Database	Required permissions	Actions
Source ApsaraDB RDS for MySQL instance	Read permissions on the objects to be migrated.	Create an account and Modify account permissions.

Note

Source database accounts not created and authorized in the ApsaraDB RDS for MySQL console must have the REPLICATION CLIENT, REPLICATION SLAVE, SHOW VIEW, and SELECT permissions.

Procedure

Navigate to the migration task list page for the destination region using one of the following methods.
From the DTS console
1. Log on to the Data Transmission Service (DTS) console.
2. In the navigation pane on the left, click Data Migration.
3. In the upper-left corner of the page, select the region where the migration instance is located.
From the DMS console

Note
The actual operations may vary based on the mode and layout of the DMS console. For more information, see Simple mode console and Customize the layout and style of the DMS console.
1. Log on to the Data Management (DMS) console.
2. In the top menu bar, choose Data + AI > Data Transmission (DTS) > Data Migration.
3. To the right of Data Migration Tasks, select the region where the migration instance is located.
Click Create Task to navigate to the task configuration page.

Configure the source and destination databases.

Category	Parameter	Description
N/A	Task Name	DTS automatically generates a task name. We recommend that you specify a descriptive name for easy identification. The name does not need to be unique.
Source Database	Select Existing Connection	To use a database instance that has been added to the system (created or saved), select the desired database instance from the drop-down list. The database information below will be automatically configured. Note In the DMS console, this parameter is named Select a DMS database instance.. If you have not registered the database instance with the system, or do not need to use a registered instance, manually configure the database information below.
	Database Type	Select MySQL.
	Access Method	Select Alibaba Cloud Instance.
	Instance Region	Select the region where the source ApsaraDB RDS for MySQL instance is located.
	Replicate Data Across Alibaba Cloud Accounts	In this example, a database instance under the current Alibaba Cloud account is used. Select No.
	RDS Instance ID	Select the ID of the source ApsaraDB RDS for MySQL instance.
	Database Account	Enter the database account of the source ApsaraDB RDS for MySQL instance. For information about the required permissions, see Permissions required for database accounts.
	Database Password	Enter the password for the database account.
	Encryption	Select Non-encrypted or SSL-encrypted as needed. If you set this to SSL-encrypted, you must enable SSL encryption for the RDS for MySQL instance beforehand. For more information, see Use a cloud certificate to quickly enable SSL link encryption.
Destination Database	Select Existing Connection	To use a database instance that has been added to the system (created or saved), select the desired database instance from the drop-down list. The database information below will be automatically configured. Note In the DMS console, this parameter is named Select a DMS database instance.. If you have not registered the database instance with the system, or do not need to use a registered instance, manually configure the database information below.
	Database Type	Select RocketMQ.
	Access Method	Select Alibaba Cloud Instance.
	Instance Region	Select the region where the destination ApsaraMQ for RocketMQ instance is located.
	RocketMQ version	Select the version of the destination ApsaraMQ for RocketMQ instance.
	Instance ID	Select the ID of the destination ApsaraMQ for RocketMQ instance.
	Database Account	Enter the database account and password for the destination ApsaraMQ for RocketMQ instance. Note These parameters are required only when you set RocketMQ version to 5.x. You can obtain the credentials on the Intelligent Authentication tab of the RAM page in the ApsaraMQ for RocketMQ console.
	Database Password
	Topic	From the drop-down list, select the topic that will receive the migrated data.
	Topic That Stores DDL Information	From the drop-down list, select the topic that will store DDL information. Note If you do not select a topic, DDL information is stored by default in the topic specified for the Topic parameter.

After you complete the configuration, click Test Connectivity and Proceed at the bottom of the page.
Note
- Ensure that the IP address segment of the DTS service is automatically or manually added to the security settings of the source and destination databases to allow access from DTS servers. For more information, see Add DTS server IP addresses to a whitelist.
- If the source or destination database is a self-managed database (the Access Method is not Alibaba Cloud Instance), you must also click Test Connectivity in the CIDR Blocks of DTS Servers dialog box that appears.

Configure the task objects.

On the Configure Objects page, configure the objects that you want to migrate.

Parameter	Description
Migration Types	If you only need to perform a full migration, select Full Data Migration. To perform a migration with no downtime, select both Full Data Migration and Incremental Data Migration. Note If you do not select Incremental Data Migration, do not write new data to the source instance during data migration to ensure data consistency.
Processing Mode of Conflicting Tables	Precheck and Report Errors: Checks whether tables with the same names exist in the destination database. If no tables with the same names exist, the precheck is passed. If tables with the same names exist, an error is reported during the precheck, and the data migration task does not start. Note If a table in the destination database has the same name but cannot be easily deleted or renamed, you can change the name of the table in the destination database. For more information, see Object name mapping. Ignore Errors and Proceed: Skips the check for tables with the same names. Warning Selecting Ignore Errors and Proceed may cause data inconsistency and business risks. For example: If the table schemas are consistent and a record in the destination database has the same primary key value as a record in the source database: During full migration, DTS keeps the record in the destination database. The record from the source database is not migrated. During incremental migration, DTS does not keep the record in the destination database. The record from the source database overwrites the record in the destination database. If the table schemas are inconsistent, only some columns of data may be migrated, or the migration may fail. Proceed with caution.
Format of the data delivered to RocketMQ.	Select the storage format for the data that is written to the destination topic based on your business requirements. For more information, see Data storage formats in a message queue.
Synchronize all fields	When an UPDATE statement runs on the source, DTS migrates a pre-image to the old field in the destination topic. This setting controls whether the pre-image includes the entire row or only the updated fields. Note This parameter is available only when you set Format of the data delivered to RocketMQ. to Canal JSON. Yes: Migrates the pre-image of the entire row that contains the updated fields. No (Default): Migrates only the pre-image of the updated fields.
Rules of the ordered messages delivered to RocketMQ.	Select the ordering rule for messages written to the destination topic based on your business requirements. For more information, see Message ordering rules for ApsaraMQ for RocketMQ.
Name of DTS producer group	Specify a producer group (ProducerGroup) to send messages in the destination topic based on your business requirements. For more information, see Producers. Note The default value is dts-producer-group.
Limits of RocketMQ messaging transactions per second (TPS)	Specify the maximum messaging TPS for data written to the destination topic. For more information about messaging TPS, see Computing specifications. Important The value must be less than or equal to the maximum TPS of the ApsaraMQ for RocketMQ instance. For more information, see Instance specifications. While the migration instance is running, the actual messaging TPS of the ApsaraMQ for RocketMQ instance may fluctuate slightly around the specified value.
Whether to filter large size of records.	Specify whether to filter out messages larger than 4 MB from being written to the destination topic. Important If you select No, the migration instance fails when a message larger than 4 MB is written to the destination topic.
Capitalization of Object Names in Destination Instance	You can configure the case sensitivity policy for the names of migrated objects, such as databases, tables, and columns, in the destination instance. By default, DTS default policy is selected. You can also choose to keep the case sensitivity consistent with the default policy of the source or destination database. For more information, see Case sensitivity of object names in the destination database.
Source Objects	In the Source Objects box, click the objects to migrate, and then click to move them to the Selected Objects box. Note You can select databases or tables as migration objects.
Selected Objects	In this example, no additional configuration is required. You can use the mapping feature to specify the topic name for the destination ApsaraMQ for RocketMQ instance, set filter conditions, select SQL operations to migrate, and set a partition key. For more information, see object name mapping.

Click Next: Advanced Settings to configure advanced parameters.

Parameter	Description
Dedicated Cluster for Task Scheduling	By default, DTS schedules tasks on a shared cluster. You do not need to select one. If you want more stable tasks, you can purchase a dedicated cluster to run DTS migration tasks.
Retry Time for Failed Connections	After the migration task starts, if the connection to the source or destination database fails, DTS reports an error and immediately begins to retry the connection. The default retry duration is 720 minutes. You can customize the retry time to a value from 10 to 1440 minutes. We recommend that you set the duration to more than 30 minutes. If DTS reconnects to the source and destination databases within the specified duration, the migration task automatically resumes. Otherwise, the task fails. Note For multiple DTS instances that share the same source or destination, the network retry time is determined by the setting of the last created task. Because you are charged for the task during the connection retry period, we recommend that you customize the retry time based on your business needs, or release the DTS instance as soon as possible after the source and destination database instances are released.
Retry Time for Other Issues	After the migration task starts, if a non-connectivity issue, such as a DDL or DML execution exception, occurs in the source or destination database, DTS reports an error and immediately begins to retry the operation. The default retry duration is 10 minutes. You can customize the retry time to a value from 1 to 1440 minutes. We recommend that you set the duration to more than 10 minutes. If the related operations succeed within the specified retry duration, the migration task automatically resumes. Otherwise, the task fails. Important The value of Retry Time for Other Issues must be less than the value of Retry Time for Failed Connections.
Enable Throttling for Full Data Migration	During full migration, DTS consumes read and write resources on the source and destination databases, which may increase the database load. If required, you can enable throttling for the full migration task. You can set Queries per second (QPS) to the source database, RPS of Full Data Migration, and Data migration speed for full migration (MB/s) to reduce the load on the destination database. Note This configuration item is available only if you select Full Data Migration for Migration Types. You can also adjust the full migration speed after the migration instance is running.
Enable Throttling for Incremental Data Migration	If required, you can also choose to set speed limits for the incremental migration task. You can set RPS of Incremental Data Migration and Data migration speed for incremental migration (MB/s) to reduce the load on the destination database. Note This configuration item is available only if you select Incremental Data Migration for Migration Types. You can also adjust the incremental migration speed after the migration instance is running.
Whether to delete SQL operations on heartbeat tables of forward and reverse tasks	Choose whether DTS writes heartbeat SQL information to the source database while the instance is running. Yes: Does not write heartbeat SQL information to the source database. The DTS instance may display latency. No: Writes heartbeat SQL information to the source database. This may interfere with source database operations like physical backups and cloning.
Environment Tag	You can select an environment tag to identify the instance. In this example, no tag is required.
Configure ETL	Choose whether to enable the extract, transform, and load (ETL) feature. For more information, see What is ETL? Valid values: Yes: Enables the ETL feature. Enter data processing statements in the code editor. For more information, see Configure ETL in a data migration or data synchronization task. No: Disables the ETL feature.
Monitoring and Alerting	Select whether to set alerts and receive alert notifications based on your business needs. No: Does not set an alert. Yes: Configure alerts by setting an alert threshold and an alert contact. If a migration fails or the latency exceeds the threshold, the system sends an alert notification.

Save the task and run a precheck.
- To view the parameters for configuring this instance when you call the API operation, move the pointer over the Next: Save Task Settings and Precheck button and click Preview OpenAPI parameters in the bubble that appears.
- If you do not need to view or have finished viewing the API parameters, click Next: Save Task Settings and Precheck at the bottom of the page.
Note
- Before the migration task starts, DTS performs a precheck. The task starts only after it passes the precheck.
- If the precheck fails, click View Details next to the failed check item, fix the issue based on the prompt, and then run the precheck again.
- If a warning is reported during the precheck:
  
  For check items that cannot be ignored, click View Details next to the failed item, fix the issue based on the prompt, and then run the precheck again.
  
  For check items that can be ignored, you can click Confirm Alert Details, Ignore, OK, and Precheck Again to skip the alert item and run the precheck again. If you choose to ignore a warning, it may cause issues such as data inconsistency and pose risks to your business.

Purchase an instance.

When the Success Rate is 100%, click Next: Purchase Instance.

On the Purchase page, select the link specification for the data migration instance. For more information, see the following table.

Category	Parameter	Description
New Instance Class	Resource Group Settings	Select the resource group to which the instance belongs. The default value is default resource group. For more information, see What is Resource Management?
New Instance Class	Instance Class	DTS provides migration specifications with different performance levels. The link specification affects the migration speed. You can select a specification based on your business scenario. For more information, see Data migration link specifications.

After the configuration is complete, read and select Data Transmission Service (Pay-as-you-go) Service Terms.
Click Buy and Start. In the OK dialog box that appears, click OK.

You can view the progress of the migration task on the Data Migration Tasks list page.
Note
- If the migration task does not include incremental migration, it stops automatically after the full migration is complete. After the task stops, its Status changes to Completed.
- If the migration task includes incremental migration, it does not stop automatically. The incremental migration task continues to run. While the incremental migration task is running, the Status of the task is Running.

Mapping information

In the Selected Objects list, hover over the target topic name.
Click Edit.

In the dialog box, configure the mapping information.