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ApsaraDB for MyBase:Migrate data from an ApsaraDB MyBase for MySQL instance to an ApsaraDB RDS for MySQL instance

Last Updated:Sep 21, 2023

This topic describes how to migrate data from an ApsaraDB MyBase for MySQL instance to an ApsaraDB RDS for MySQL instance by using Data Transmission Service (DTS).

Prerequisites

Limits

Category

Description

Limits on the source database

  • 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 objects that you want to migrate and you need to edit tables (such as renaming tables or columns) in the destination database, up to 1,000 tables can be migrated 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 split the tables and configure multiple tasks to migrate the tables, or configure a task to migrate the entire database.

  • If you want to migrate incremental data, make sure that the following requirements are met:

    • The binary logging feature is enabled. The value of the binlog_format parameter is set to row. The value of the binlog_row_image parameter is set to full. Otherwise, error messages are returned during precheck and the data migration task cannot be started.

    • If you perform only incremental data migration, the binary logs of the source database must be stored for more than 24 hours. If you perform both full data migration and incremental data migration, the binary logs of the source 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. After full data migration is complete, you can set the retention period to more than 24 hours. Make sure that you set the retention period of binary logs based on the preceding requirements. Otherwise, the service reliability and performance stated in the Service Level Agreement (SLA) of DTS cannot be achieved.

  • Limits on operations to perform on the source database:

    • During schema migration and full data migration, do not perform DDL operations to change the schemas of databases or tables. Otherwise, the data migration task fails.

    • During full data migration and incremental data migration, DTS temporarily disables the constraint check and cascade operations on foreign keys at the session level. If you perform the cascade and delete operations on the source database during data migration, data inconsistency may occur.

    • If you perform only full data migration, do not write data to the source database during data migration. Otherwise, data inconsistency may occur between the source and destination databases. To ensure data consistency, we recommend that you select schema migration, full data migration, and incremental data migration as the migration types.

Other limits

  • To ensure compatibility, we recommend that you use the same engine versions for the source and destination MySQL databases.

  • Before you migrate data, evaluate the impact of data migration on the performance of the source and destination databases. We recommend that you migrate data during off-peak hours. During full data migration, DTS uses the read and write resources of the source and destination databases. This may increase the loads on the database servers.

  • During full data migration, concurrent INSERT operations cause fragmentation in the tables of the destination database. After full data migration is complete, the size of used tablespace of the destination database is larger than that of the source database.

  • You must make sure that the precision settings for columns of the FLOAT or DOUBLE data type meet your business requirements. DTS uses the ROUND(COLUMN,PRECISION) function to retrieve values from columns of the FLOAT or DOUBLE data type. If you do not specify a precision, DTS sets the precision for columns of the FLOAT data type to 38 digits and the precision for columns of the DOUBLE data type to 308 digits.

  • DTS attempts to resume data migration tasks that failed within the last seven days. Before you switch workloads to the destination database, you must stop or release the failed tasks. You can also execute the REVOKE statement to revoke the write permissions from the accounts that are used by DTS to access the destination database. Otherwise, the data in the source database overwrites the data in the destination database after the failed task is resumed.

  • If you migrate data to an ApsaraDB RDS for MySQL instance, DTS automatically creates a destination database in the ApsaraDB RDS for MySQL instance. However, if the name of the source database is invalid, you must manually create a database in the ApsaraDB RDS for MySQL instance before you configure the data migration task. For more information, see Create a database.

  • DTS updates the `dts_health_check`.`ha_health_check` table in the source database as scheduled to move forward the binary log file position.

Billing rules

Migration type

Instance configuration fee

Internet traffic fee

Schema migration and full data migration

Free of charge.

Free of charge.

Incremental data migration

Charged. For more information, see Billing overview.

Migration types

  • Schema migration

    Data Transmission Service (DTS) migrates the schemas of objects from the source database to the destination database.

    Note
    • DTS supports schema migration for the following types of objects: table, view, trigger, stored procedure, and function.

    • During schema migration, DTS changes the value of the SECURITY attribute from DEFINER to INVOKER for views, stored procedures, and functions.

    • DTS does not migrate user information. To call a view, stored procedure, or function of the destination database, you must grant the read and write permissions to INVOKER.

  • Full data migration

    DTS migrates the existing data of objects from the source database to the destination database.

  • Incremental data migration

    After full data migration is complete, DTS migrates incremental data from the source database to the destination database. Incremental data migration allows data to be migrated smoothly without interrupting services of self-managed applications during data migration.

SQL operations that can be migrated during incremental data migration

Operation type

SQL operation

DML

INSERT, UPDATE, and DELETE

DDL

  • ALTER TABLE and ALTER VIEW

  • CREATE FUNCTION, CREATE INDEX, CREATE PROCEDURE, CREATE TABLE, and CREATE VIEW

  • DROP INDEX and DROP TABLE

  • RENAME TABLE

  • TRUNCATE TABLE

Permissions required for database accounts

Database

Schema migration

Full data migration

Incremental data migration

ApsaraDB MyBase for MySQL instance

SELECT permission

SELECT permission

Read and write permissions

ApsaraDB RDS for MySQL instance

Read and write permissions

For information about how to create a database account and grant permissions to the database account, see the following topics:

Procedure

  1. Go to the Data Migration Tasks page.
    1. Log on to the Data Management (DMS) console.
    2. In the top navigation bar, click DTS.
    3. In the left-side navigation pane, choose DTS (DTS) > Data Migration.
    Note
  2. From the drop-down list next to Data Migration Tasks, select the region in which the data migration instance resides.
    Note If you use the new DTS console, you must select the region in which the data migration instance resides in the upper-left corner.
  3. Click Create Task. On the page that appears, configure the source and destination databases.

    Warning

    After you configure the source and destination databases, we recommend that you read the limits displayed at the top of the page. Otherwise, the task may fail or data inconsistency may occur.

    Section

    Parameter

    Description

    N/A

    Task Name

    The name of the task. DTS automatically assigns a name to the task. We recommend that you specify a descriptive name that makes it easy to identify the task. You do not need to specify a unique task name.

    Source Database

    Select an existing DMS database instance. (Optional. If you have not registered a DMS database instance, ignore this option and configure database settings in the section below.)

    The database instance that you want to use. You can choose whether to select an existing instance based on your business requirements.

    • If you select an existing instance, DTS automatically populates the parameters for the database.

    • If you do not select an existing instance, you must manually configure parameters for the database.

    Database Type

    The type of the source database. Select MySQL.

    Access Method

    The access method of the source database. Select Alibaba Cloud Instance.

    Instance Region

    The region where the source ApsaraDB MyBase for MySQL instance resides.

    Replicate Data Across Alibaba Cloud Accounts

    Specifies whether to migrate data across Alibaba Cloud accounts. In this example, No is selected.

    Note

    If you want to migrate data across different Alibaba Cloud accounts, you can select Yes. For more information, see Synchronize or migrate data across Alibaba Cloud accounts.

    RDS Instance ID

    The ID of the source ApsaraDB MyBase for MySQL instance.

    Database Account

    The database account of the source ApsaraDB MyBase for MySQL instance. For more information about the permissions that are required for the account, see the "Permissions required for database accounts" section of this topic.

    Database Password

    The password of the database account.

    Encryption

    Specifies whether to encrypt the connection to the source database. Select Non-encrypted or SSL-encrypted based on your business requirements. If you select SSL-encrypted, you must enable SSL encryption for the ApsaraDB MyBase for MySQL instance before you configure the data migration task.

    Destination Database

    Select an existing DMS database instance. (Optional. If you have not registered a DMS database instance, ignore this option and configure database settings in the section below.)

    In this example, no database instance is selected. Configure the following database information.

    Database Type

    The type of the destination database. Select MySQL.

    Access Method

    The access method of the destination database. Select Alibaba Cloud Instance.

    Instance Region

    The region where the destination ApsaraDB RDS for MySQL instance resides.

    RDS Instance ID

    The ID of the destination ApsaraDB RDS for MySQL instance.

    Database Account

    The database account of the destination ApsaraDB RDS for MySQL instance. For more information about the permissions that are required for the account, see the "Permissions required for database accounts" section of this topic.

    Database Password

    The password of the database account.

    Encryption

    Specifies whether to encrypt the connection to the destination database. Select Non-encrypted or SSL-encrypted based on your business requirements. If you select SSL-encrypted, you must enable SSL encryption for the ApsaraDB RDS for MySQL instance before you configure the data migration task. For more information, see Configure the SSL encryption feature.

  4. In the lower part of the page, click Test Connectivity and Proceed.

    If the source or destination database is an Alibaba Cloud database instance, such as an ApsaraDB RDS for MySQL or ApsaraDB for MongoDB instance, DTS automatically adds the CIDR blocks of DTS servers to the IP address whitelist of the instance. If the source or destination database is a self-managed database hosted on an Elastic Compute Service (ECS) instance, DTS automatically adds the CIDR blocks of DTS servers to the security group rules of the ECS instance, and you must make sure that the ECS instance can access the database. If the source or destination database is a self-managed database that is deployed in a data center or provided by a third-party cloud service provider, you must manually add the CIDR blocks of DTS servers to the IP address whitelist of the database to allow DTS to access the database. For more information, see the "CIDR blocks of DTS servers" section of the Add the CIDR blocks of DTS servers to the security settings of on-premises databases topic.

    Warning

    If the CIDR blocks of DTS servers are automatically or manually added to the IP address whitelist of the database instance or ECS security group rules, security risks may arise. Therefore, before you use DTS to migrate data, you must understand and acknowledge the potential risks and take preventive measures, including but not limited to the following measures: enhance the security of your account and password, limit the ports that are exposed, authenticate API calls, regularly check the IP address whitelist or ECS security group rules and forbid unauthorized CIDR blocks, and connect the database to DTS by using Express Connect, VPN Gateway, or Smart Access Gateway.

  5. Configure the objects to be migrated and advanced settings.

    Parameter

    Description

    Migration Type

    • To perform only full data migration, select Schema Migration and Full Data Migration.

    • To ensure service continuity during data migration, select Schema Migration, 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 have the same names as tables in the source database. If the source and destination databases do not contain tables that have the same names, the precheck is passed. Otherwise, an error is returned during the precheck and the data migration task cannot be started.

      Note

      You can use the object name mapping feature to rename the tables that are migrated to the destination database. You can use this feature if the source and destination databases contain tables that have identical names and the tables in the destination database cannot be deleted or renamed. 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 potential risks.

      • If the source and destination databases have the same schema, DTS does not migrate data records that have the same primary keys as data records in the destination database.

      • If the source and destination databases have different schemas, only specific columns are migrated or the data migration task fails. Proceed with caution.

    • Precheck and Report Errors: checks whether the destination database contains collections that have the same names as collections in the source database. If the source and destination databases do not contain collections that have identical names, the precheck is passed. Otherwise, an error is returned during the precheck and the data migration task cannot be started.

      Note

      You can use the object name mapping feature to rename the collections that are migrated to the destination database. You can use this feature if the source and destination databases contain collections that have identical names and the collections in the destination database cannot be deleted or renamed. For more information, see Map object names.

    • Ignore Errors and Proceed: skips the precheck for identical collection 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 potential risks.

      • DTS does not migrate data records that have the same primary keys as data records in the destination database.

      • Data may fail to be initialized, only specific columns are migrated, or the data migration task fails.

    • Precheck and Report Errors: checks whether the destination database contains tables that have the same names as tables in the source database. If the source and destination databases do not contain tables that have the same names, the precheck is passed. Otherwise, an error is returned during the precheck and the data migration task cannot be started.

    • 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 potential risks.

      • If the source and destination databases have the same schema, DTS does not migrate data records that have the same primary keys as data records in the destination database.

      • If the source and destination databases have different schemas, only specific columns are migrated or the data migration task fails. Proceed with caution.

    Method to Migrate Triggers in Source Database

    The method that is used to migrate triggers from the source database. You can select a migration method based on your business requirements. If no triggers are to be migrated, you do not need to configure this parameter. For more information, see Synchronize or migrate triggers from the source database.

    Enable Migration Assessment

    Specifies whether to enable migration assessment. For example, check whether the schemas of the objects to be migrated meet the requirements of the destination database. You can select Yes or No based on your business requirements.

    Note

    If you select Yes, the precheck may take more time. You can view the Assessment Result during the precheck. The assessment results do not affect the precheck results.

    Capitalization of Object Names in Destination Instance

    The capitalization of database names, table names, and column names in the destination database. By default, DTS default policy is selected. You can select other options to ensure that the capitalization of object names is consistent with that in 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 and click the Rightwards arrow icon to add the objects to the Selected Objects section.

    Note

    You can select columns, tables, or databases as the objects to be migrated. If you select tables or columns as the objects to be migrated, DTS does not migrate other objects such as views, triggers, or stored procedures to the destination database.

    Selected Objects

    • To rename an object that you want to migrate to the destination instance, right-click the object in the Selected Objects section. For more information, see Map the name of a single object.

    • To rename multiple objects at a time, click Batch Edit in the upper-right corner of the Selected Objects section. For more information, see Map multiple object names at a time.

    Note
    • If you use the object name mapping feature to rename an object, other objects that are dependent on the object may fail to be migrated.

    • To specify WHERE conditions to filter data, right-click an object in the Selected Objects section. In the dialog box that appears, specify the conditions. For more information, see Use SQL conditions to filter data.

    • To migrate DML or DDL operations performed on a specific database or table, right-click the object in the Selected Objects section. In the dialog box that appears, select the DML or DDL operations on which you want to perform incremental data migration. For more information about the operations, see the "SQL operations that can be migrated during incremental data migration" section of this topic.

  6. Click Next: Advanced Settings to configure advanced settings.

    • Data Verification Settings

      For more information about how to enable data verification, see Enable data verification.

    • Advanced settings

      Parameter

      Description

      Set Alerts

      Specifies whether to set alerts for the data migration task. If the task fails or the migration latency exceeds the threshold, the alert contacts will receive notifications. Valid values:

      Copy the temporary table of the Online DDL tool that is generated in the source table to the destination database

      If you use DMS or the gh-ost tool to perform online DDL operations on the source database, you can specify whether to migrate the temporary tables generated by online DDL operations. Valid values:

      Important

      You cannot use tools such as pt-online-schema-change to perform online DDL operations on the source database. Otherwise, the DTS task fails.

      • Yes: DTS migrates the data of temporary tables generated by online DDL operations.

        Note

        If online DDL operations generate a large amount of data, the data migration task may take an extended period of time to complete.

      • No, Adapt to DMS Online DDL: DTS does not migrate the data of temporary tables generated by online DDL operations. Only the original DDL operations that are performed by using DMS are migrated.

        Note

        If you select No, Adapt to DMS Online DDL, the tables in the destination database may be locked.

      • No, Adapt to gh-ost: DTS does not migrate the data of temporary tables generated by online DDL operations. Only the original DDL operations that are performed by using the gh-ost tool are migrated. You can use the default or custom regular expressions to filter out the shadow tables of the gh-ost tool and tables that are not required.

        Note

        If you select No, Adapt to gh-ost, the tables in the destination database may be locked.

      Whether to Migrate Accounts

      Specifies whether to migrate the account information of the source database based on your business requirements. If you select Yes, you must select the accounts that you want to migrate and check the permissions of the source and destination database accounts used in the data migration task.

      Important
      • The source and destination database accounts used in the data migration task must have the SELECT permission on the mysql.user, mysql.db, mysql.columns_priv, and mysql.tables_priv metadata tables.

      • The accounts that already exist in the destination database and the system accounts of the source database, such as root, mysql.infoschema, mysql.session, and mysql.sys, cannot be migrated.

      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 1440. Unit: minutes. Default value: 720. We recommend that you set the parameter to a value greater than 30. If DTS reconnects 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 set different retry time ranges for multiple data migration tasks that share the same source or destination instance, the value that is set 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 your earliest opportunity after the source database and destination instances are released.

      The wait time before a retry when other issues occur in the source and destination databases.

      The retry time range for other issues. For example, if the DDL or DML operations fail to be performed after the data migration task is started, DTS immediately retries the operations within the 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 time range, DTS resumes the data migration task. Otherwise, the data migration task fails.

      Important

      The value of the The wait time before a retry when other issues occur in the source and destination databases parameter must be smaller than the value of the Retry Time for Failed Connections parameter.

      Configure ETL

      Specifies whether to configure the extract, transform, and load (ETL) feature. For more information, see What is ETL? Valid values:

  7. In the lower part of the page, click Next: Save Task Settings and Precheck.

    You can move the pointer over Next: Save Task Settings and Precheck and click Preview OpenAPI parameters to view the parameters to be specified when you call the relevant API operation to configure the DTS task.

    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 troubleshoot the issues based on the causes, 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 an 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.

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

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

    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?.

    Instance Class

    DTS provides various instance classes that vary in the migration speed. You can select an instance class based on your business scenario. For more information, see Specifications of data migration instances.

  10. Read and select the check box to agree to Data Transmission Service (Pay-as-you-go) Service Terms.

  11. Click Buy and Start to start the data migration task. You can view the progress of the task in the task list.