Migrate data from a MySQL database to an ApsaraMQ for RocketMQ instance - Data Transmission Service

Data Transmission Service (DTS) supports data migration from a MySQL database, such as a self-managed MySQL database or an RDS for MySQL instance, to an ApsaraMQ for RocketMQ instance. This topic describes how to migrate data from an RDS for MySQL instance.

Prerequisites

You have created a destination ApsaraMQ for RocketMQ instance that is not a Serverless instance. For more information, see Manage instances or Manage instances.
Note
For information about the supported versions of the source and destination databases, see Migration solutions.
You have created a topic in the destination ApsaraMQ for RocketMQ instance to receive the data. For more information, see Manage topics or Manage topics.
Important
For 4.x series instances, set the Message Type to Partitionally Ordered Message.
For 5.x series instances, set Message Type to Ordered Message.

Precautions

Type	Description
Source database limits	The server on which the source database is deployed must have sufficient outbound bandwidth. Otherwise, the data migration speed decreases. Migration objects: The tables to be migrated must have PRIMARY KEY or UNIQUE constraints and all fields must be unique. Otherwise, the destination database may contain duplicate data records. If you select tables as the objects to be migrated and you want to modify the tables in the destination database, such as renaming tables or columns, you can migrate up to 1,000 tables in a single data migration task. If you run a task to migrate more than 1,000 tables, a request error occurs. In this case, we recommend that you configure multiple tasks to migrate the tables or configure a task to migrate the entire database. If you want to migrate incremental data, the following requirements for binary logs must be met: The binary logging feature is enabled. The binlog_format parameter is set to row and the binlog_row_image parameter is set to full. Otherwise, error messages are returned during the precheck and the data migration task fails to be started. Important If the source database is a self-managed MySQL database deployed in a dual-primary cluster, you must set the log_slave_updates parameter to ON. This ensures that DTS can obtain all binary logs. The binary logs of an ApsaraDB RDS for MySQL instance must be stored for at least three days. We recommend that you store the binary logs seven days. The binary logs of a self-managed MySQL database must be stored for at least seven days. Otherwise, DTS may fail to obtain the binary logs and the task may fail. In exceptional circumstances, data inconsistency or loss may occur. Make sure that you configure the retention period of binary logs based on the preceding requirements. Otherwise, the service reliability or performance stated in the Service Level Agreement (SLA) of DTS may not be guaranteed. Note For more information about how to set Retention Period of the binary logs of an ApsaraDB RDS for MySQL instance, see Configure parameters based on which the system automatically deletes the binary log files of an RDS instance. During the full data migration phase, do not perform DDL operations to change the database or table schemas. Otherwise, the data migration task fails. Note DTS queries the source database during the full migration phase. This creates metadata locks, which may block DDL operations on the source database. If you perform only full data migration, do not write new data to the source database. Otherwise, data becomes inconsistent between the source and destination. To maintain real-time data consistency, select both full data migration and incremental data migration. The data generated by change operation of binary logs, such as data restored from a physical backup or data from a cascade operation, is not recorded and migrated to the destination database when the data migration instance is running. Note If the change data is not recorded and migrated to the destination database, you can migrate full data again on the premise that your business is not affected. If the source database is MySQL database 8.0.23 or later, and the data to be migrated includes invisible columns, the data of the columns cannot be obtained and data loss occurs. Note To make the columns visible, run the `ALTER TABLE <table_name> ALTER COLUMN <column_name> SET VISIBLE;` command. For more information, see Invisible Columns. Tables that do not have primary keys automatically generate invisible primary keys. You need to make the invisible primary keys visible. For more information, see Generated Invisible Primary Keys.
Other limits	A Serverless ApsaraMQ for RocketMQ instance cannot be used 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 is in a region different from the Instance Region of the source database, DTS accesses the destination ApsaraMQ for RocketMQ instance through its public endpoint. This incurs data transfer costs. You must ensure that public access is enabled for the destination ApsaraMQ for RocketMQ instance. Note You can check the Internet access status on the Basic Information tab of the Instance Details page in the ApsaraMQ for RocketMQ console. For information about the Internet traffic costs of the destination ApsaraMQ for RocketMQ instance, see Internet traffic pricing. 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 you want to upgrade or downgrade the class of the destination ApsaraMQ for RocketMQ instance in DTS, the message is delivered in a new rule configuration different from before. During full data migration, DTS consumes some read and write resources of the source and destination databases. This may increase the database load. Before you migrate data, evaluate the performance of the source and destination databases. We recommend that you perform data migration during off-peak hours, for example, when the CPU load of both databases is below 30%. Full data migration involves concurrent INSERT operations, which cause table fragmentation in the destination database. After the full migration is complete, the table storage space in the destination database is 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 fails. If data is written to the destination database from sources other than DTS during the migration, data inconsistency may occur. If the always-encrypted (EncDB) feature is enabled for the RDS for MySQL instance, full data migration is not supported. Note An RDS for MySQL instance with Transparent Data Encryption (TDE) enabled supports both full and incremental data migration. If an instance fails, DTS helpdesk will try to recover the instance within 8 hours. During the recovery process, operations such as restarting the instance and adjusting parameters may be performed. Note When parameters are adjusted, only the parameters of the DTS instance are modified. The parameters of the database are not modified. The parameters that may be modified include but are not limited to those described in Modify instance parameters.
Special cases	If the source database is a self-managed MySQL database, take note of the following limits: If you perform a primary/secondary switchover on the source database when the data migration task is running, the task fails. DTS calculates migration latency based on the timestamp of the latest migrated data in the destination database and the current timestamp in the source database. If no DML operation is performed on the source database for a long time, the migration latency may be inaccurate. If the latency of the data migration task is excessively high, you can perform a DML operation on the source database to update the latency. Note If you select an entire database as the object to be migrated, you can create a heartbeat table. The heartbeat table is updated or receives data every second. DTS executes the CREATE DATABASE IF NOT EXISTS `test` statement in the source database as scheduled to move forward the binary log file position. If the source database is an Apsara RDS for MySQL instance, take note of the following limit: In incremental data migration, an ApsaraDB RDS for MySQL instance that does not record transaction logs, such as a read-only ApsaraDB RDS for MySQL V5.6 instance, cannot be used as the source database. DTS executes the CREATE DATABASE IF NOT EXISTS `test` statement in the source database as scheduled to move forward the binary log file position.

Billing

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

SQL operations that can be incrementally migrated

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

Permissions required for database accounts

Database	Required permissions	How to create and grant permissions
Source RDS for MySQL	Read permissions on the migration objects.	Create an account and Modify account permissions.

Note

If the database account for the source database was not created and authorized in the RDS for MySQL console, ensure that the account has the REPLICATION CLIENT, REPLICATION SLAVE, SHOW VIEW, and SELECT permissions.

Procedure

Use one of the following methods to go to the Data Migration page and select the region in which the data migration instance resides.
DTS console
1. Log on to the DTS console.
2. In the left-side navigation pane, click Data Migration.
3. In the upper-left corner of the page, select the region in which the data migration instance resides.
DMS console
Note
The actual operation may vary based on the mode and layout of the DMS console. For more information, see Simple mode and Customize the layout and style of the DMS console.
1. Log on to the DMS console.
2. In the top navigation bar, move the pointer over Data + AI > DTS (DTS) > Data Migration.
3. From the drop-down list to the right of Data Migration Tasks, select the region in which the data synchronization instance resides.
Click Create Task to go to the task configuration page.

Configure the source and destination databases. The following table describes the parameters.

Category	Configuration	Description
N/A	Task Name	The name of the DTS task. DTS automatically generates a task name. We recommend that you specify an informative name that makes it easy to identify the task. You do not need to specify a unique task name.
Source Database	Select Existing Connection	If you use a database instance that is registered with DTS, select the instance from the drop-down list. DTS automatically populates the following database parameters for the instance. For more information, see Manage database connections. Note In the DMS console, you can select the database instance from the Select a DMS database instance drop-down list. If you fail to register the instance with DTS, or you do not need to use the instance that is registered with DTS, you must configure the following database information.
	Database Type	Select MySQL.
	Access Method	Select Alibaba Cloud Instance.
	Instance Region	Select the region where the source RDS for MySQL instance resides.
	Replicate Data Across Alibaba Cloud Accounts	In this example, a database instance of the current Alibaba Cloud account is used. Select No.
	RDS Instance ID	Select the ID of the source RDS for MySQL instance.
	Database Account	Enter the database account for the source RDS for MySQL instance. For permission requirements, see Permissions required for database accounts.
	Database Password	The password that is used to access the database instance.
	Encryption	Specifies whether to encrypt the connection to the database. You can select Non-encrypted or SSL-encrypted based on your business requirements. If you want to set this parameter to SSL-encrypted, you must enable SSL encryption for the ApsaraDB RDS for MySQL instance before you configure the DTS task. For more information, see Use a cloud certificate to enable SSL encryption.
Destination Database	Select Existing Connection	If you use a database instance that is registered with DTS, select the instance from the drop-down list. DTS automatically populates the following database parameters for the instance. For more information, see Manage database connections. Note In the DMS console, you can select the database instance from the Select a DMS database instance drop-down list. If you fail to register the instance with DTS, or you do not need to use the instance that is registered with DTS, you must configure the following database information.
	Database Type	Select RocketMQ.
	Access Method	Select Alibaba Cloud Instance.
	Instance Region	Select the region where the destination ApsaraMQ for RocketMQ instance resides.
	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 if you set RocketMQ version to 5.x. You can obtain the credentials on the Intelligent Identity Recognition tab of the Access Control page in the ApsaraMQ for RocketMQ console.
	Database Password
	Topic	From the drop-down list, select the topic to receive data.
	Topic That Stores DDL Information	From the drop-down list, select the topic to store DDL information. Note If you do not select a topic, DDL information is stored in the topic selected for the Topic parameter.

In the lower part of the page, click Test Connectivity and Proceed.
Note
- Make sure that the CIDR blocks of DTS servers can be 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 and its Access Method is not set to Alibaba Cloud Instance, click Test Connectivity in the CIDR Blocks of DTS Servers dialog box.

Configure the objects to be migrated.

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

Configuration	Description
Migration Types	To perform only full data migration, select only Full Data Migration. To ensure service continuity during data migration, select Full Data Migration and Incremental Data Migration. Note If you do not select Incremental Data Migration, we recommend that you do not write data to the source database during data migration. This ensures data consistency between the source and destination databases.
Processing Mode of Conflicting Tables	Precheck and Report Errors: checks whether the destination database contains tables that use the same names as tables in the source database. If the source and destination databases do not contain tables that have identical table names, the precheck is passed. Otherwise, an error is returned during the precheck and the data migration task cannot be started. Note If the source and destination databases contain tables with identical names and the tables in the destination database cannot be deleted or renamed, you can use the object name mapping feature to rename the tables that are migrated to the destination database. For more information, see Map object names. Ignore Errors and Proceed: skips the precheck for identical table names in the source and destination databases. Warning If you select Ignore Errors and Proceed, data inconsistency may occur and your business may be exposed to the following potential risks: If the source and destination databases have the same schema, and a data record has the same primary key as an existing data record in the destination database, the following scenarios may occur: During full data migration, DTS does not migrate the data record to the destination database. The existing data record in the destination database is retained. During incremental data migration, DTS migrates the data record to the destination database. The existing data record in the destination database is overwritten. If the source and destination databases have different schemas, only specific columns are migrated or the data migration task fails. Proceed with caution.
Format of the data delivered to RocketMQ.	Select the required storage format for the data that is written to the destination topic. For more information, see Data formats in message queues.
Synchronize all fields	Specify whether to migrate only the pre-image of updated fields from the source object to the old field of the destination topic. The pre-image is the data of a record before it is updated. Note This configuration item becomes available only if you set Format of the data delivered to RocketMQ. to Canal JSON. Yes: Migrates the pre-image of the entire row when a field in that row is updated by an `UPDATE` statement. No (default): Migrates only the pre-image of updated fields in an `UPDATE` statement.
Rules of the ordered messages delivered to RocketMQ.	Select the required message order rule for writing data to the destination topic. For more information, see Message order rules for RocketMQ.
Name of DTS producer group	Set the required producer group (ProducerGroup) that sends messages to the destination topic. For more information, see Producers. Note The default value is dts-producer-group.
Limits of RocketMQ messaging transactions per second (TPS)	You can set the maximum number of messaging transactions per second (TPS) when data is 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 type limits. While the migration instance is running, the actual message TPS of the ApsaraMQ for RocketMQ instance may fluctuate slightly around the set value.
Whether to filter large size of records.	Select whether to prevent message bodies larger than 4 MB from being written to the destination topic. Important If you select No and a message body written to the destination topic exceeds 4 MB, the migration instance fails.
Capitalization of Object Names in Destination Instance	The capitalization of database names, table names, and column names in the destination instance. By default, DTS default policy is selected. You can select other options to make sure that the capitalization of object names is consistent with that of the source or destination database. For more information, see Specify the capitalization of object names in the destination instance.
Source Objects	Select one or more objects from the Source Objects section. Click the icon to add the objects to the Selected Objects section. Note You can select objects at the database or table level.
Selected Objects	No additional configuration is required for this example. You can use the mapping feature to set the topic name in the destination ApsaraMQ for RocketMQ instance, set filter conditions, select SQL operations to migrate, and set a partition key. For more information, see Mapping information.

Click Next: Advanced Settings to configure advanced settings.

Configuration	Description
Dedicated Cluster for Task Scheduling	By default, DTS schedules the data migration task to the shared cluster if you do not specify a dedicated cluster. If you want to improve the stability of data migration tasks, purchase a dedicated cluster. For more information, see What is a DTS dedicated cluster.
Retry Time for Failed Connections	The retry time range for failed connections. If the source or destination database fails to be connected after the data migration task is started, DTS immediately retries a connection within the retry time range. Valid values: 10 to 1,440. Unit: minutes. Default value: 720. We recommend that you set the parameter to a value greater than 30. If DTS is reconnected to the source and destination databases within the specified retry time range, DTS resumes the data migration task. Otherwise, the data migration task fails. Note If you specify different retry time ranges for multiple data migration tasks that share the same source or destination database, the value that is specified later takes precedence. When DTS retries a connection, you are charged for the DTS instance. We recommend that you specify the retry time range based on your business requirements. You can also release the DTS instance at the earliest opportunity after the source database and destination instance are released.
Retry Time for Other Issues	The retry time range for other issues. For example, if DDL or DML operations fail to be performed after the data migration task is started, DTS immediately retries the operations within the retry time range. Valid values: 1 to 1440. Unit: minutes. Default value: 10. We recommend that you set the parameter to a value greater than 10. If the failed operations are successfully performed within the specified retry time range, DTS resumes the data migration task. Otherwise, the data migration task fails. Important The value of the Retry Time for Other Issues parameter must be smaller than the value of the Retry Time for Failed Connections parameter.
Enable Throttling for Full Data Migration	Specifies whether to enable throttling for full data migration. During full data migration, DTS uses the read and write resources of the source and destination databases. This may increase the loads of the database servers. You can enable throttling for full data migration based on your business requirements. To configure throttling, you must configure the Queries per second (QPS) to the source database, RPS of Full Data Migration, and Data migration speed for full migration (MB/s) parameters. This reduces the loads of the destination database server. Note You can configure this parameter only if you select Full Data Migration for the Migration Types parameter.
Enable Throttling for Incremental Data Migration	Specifies whether to enable throttling for incremental data migration. To configure throttling, you must configure the RPS of Incremental Data Migration and Data migration speed for incremental migration (MB/s) parameters. This reduces the loads of the destination database server. Note You can configure this parameter only if you select Incremental Data Migration for the Migration Types parameter.
Whether to delete SQL operations on heartbeat tables of forward and reverse tasks	Specifies whether to write SQL operations on heartbeat tables to the source database while the DTS instance is running. Valid values: Yes: does not write SQL operations on heartbeat tables. In this case, a latency of the DTS instance may be displayed. No: writes SQL operations on heartbeat tables. In this case, features such as physical backup and cloning of the source database may be affected.
Environment Tag	You can select an environment tag to identify the instance if required. No selection is required for this example.
Configure ETL	Specifies whether to enable the extract, transform, and load (ETL) feature. For more information, see What is ETL? Valid values: Yes: configures the ETL feature. You can enter data processing statements in the code editor. For more information, see Configure ETL in a data migration or data synchronization task. No: does not configure the ETL feature.
Monitoring and Alerting	Specifies whether to configure alerting for the data migration task. If the task fails or the migration latency exceeds the specified threshold, the alert contacts receive notifications. Valid values: No: does not configure alerting. Yes: configures alerting. In this case, you must also configure the alert threshold and alert notification settings. For more information, see the Configure monitoring and alerting when you create a DTS task section of the Configure monitoring and alerting topic.

Save the task settings and run a precheck.
- To view the parameters to be specified when you call the relevant API operation to configure the DTS task, move the pointer over Next: Save Task Settings and Precheck and click Preview OpenAPI parameters.
- If you do not need to view or have viewed the parameters, click Next: Save Task Settings and Precheck in the lower part of the page.
Note
- Before you can start the data migration task, DTS performs a precheck. You can start the data migration task only after the task passes the precheck.
- If the task fails to pass the precheck, click View Details next to each failed item. After you analyze the causes based on the check results, troubleshoot the issues. Then, run a precheck again.
- If an alert is triggered for an item during the precheck:
  If an alert item cannot be ignored, click View Details next to the failed item and troubleshoot the issues. Then, run a precheck again.
  If the alert item can be ignored, click Confirm Alert Details. In the View Details dialog box, click Ignore. In the message that appears, click OK. Then, click Precheck Again to run a precheck again. If you ignore the alert item, data inconsistency may occur, and your business may be exposed to potential risks.

Purchase the instance.

Wait until Success Rate becomes 100%. Then, click Next: Purchase Instance.

On the Purchase Instance page, configure the Instance Class parameter for the data migration instance. The following table describes the parameters.

Section	Parameter	Description
New Instance Class	Resource Group	The resource group to which the data migration instance belongs. Default value: default resource group. For more information, see What is Resource Management?
New Instance Class	Instance Class	DTS provides instance classes that vary in the migration speed. You can select an instance class based on your business scenario. For more information, see Instance classes of data migration instances.

Read and agree to Data Transmission Service (Pay-as-you-go) Service Terms by selecting the check box.
Click Buy and Start. In the message that appears, click OK.
You can view the progress of the task on the Data Migration page.
Note
- If a data migration task cannot be used to migrate incremental data, the task automatically stops. The Completed is displayed in the Status section.
- If a data migration task can be used to migrate incremental data, the task does not automatically stop. The incremental data migration task never stops or completes. The Running is displayed in the Status section.

Mapping information

In the Selected Objects list box, hover the mouse pointer over the destination topic.
Click Edit next to the topic name.

In the dialog box that appears, configure the mapping information.