This topic describes how to migrate full data from an Amazon Aurora PostgreSQL instance to an ApsaraDB RDS for PostgreSQL instance by using Data Transmission Service (DTS).

Prerequisites

  • An Amazon Aurora PostgreSQL instance is created and the database version is 9.4, 9.5, 9.6, or 10.0.
  • The Public accessibility option of the Amazon Aurora PostgreSQL instance is set to Yes. This ensures that DTS can access the Amazon Aurora PostgreSQL instance over the Internet.
  • An ApsaraDB RDS for PostgreSQL instance is created. For more information, see Create an ApsaraDB RDS for PostgreSQL instance.
    Note The database version of the ApsaraDB RDS for PostgreSQL instance is 9.4 or 10.0.
  • The available storage space of the ApsaraDB RDS for PostgreSQL instance is larger than the total size of the data in the Amazon Aurora PostgreSQL instance.

Precautions

  • DTS uses read and write resources of the source and destination databases during full data migration. This may increase the load of the database server. If the database performance is unfavorable, the specification is low, or the data volume is large, database services may become unavailable. For example, DTS occupies a large amount of read and write resources in the following cases: a large number of slow SQL queries are performed on the source database, the tables have no primary keys, or a deadlock occurs in the destination database. 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. For example, you can migrate data when the CPU utilization of the source and destination databases is less than 30%.
  • You cannot use DTS to migrate incremental data from an Amazon Aurora PostgreSQL instance to an ApsaraDB RDS for PostgreSQL instance. Before you start the data migration task, you must stop the services that run on the Amazon Aurora PostgreSQL instance. To ensure data consistency, we recommend that you do not write data to the Amazon Aurora PostgreSQL instance during data migration.
  • A single data migration task can migrate data from only one database. To migrate data from multiple databases, you must create a data migration task for each database.
  • Functions that are written in the C programming language cannot be migrated.
  • The tables to be migrated in the source database must have PRIMARY KEY or UNIQUE constraints and all fields must be unique. Otherwise, the destination database may contain duplicate data records.
  • If a data migration task fails, DTS automatically resumes the task. Before you switch your workloads to the destination instance, stop or release the data migration task. Otherwise, the data in the source instance will overwrite the data in the destination instance after the task is resumed.

Billing

Migration type Instance configuration fee Internet traffic fee
Schema migration and full data migration Free of charge Charged only when data is migrated from Alibaba Cloud over the Internet. For more information, see Pricing.

Migration types

  • Schema migration

    DTS migrates the schemas of the required objects to the ApsaraDB RDS for PostgreSQL instance. DTS supports schema migration for the following types of objects: table, trigger, view, sequence, function, user-defined type, rule, domain, operation, and aggregate.

  • Full data migration

    DTS migrates historical data of the required objects from the Amazon RDS for PostgreSQL instance to the ApsaraDB RDS for PostgreSQL instance.

Permissions required for database accounts

Database Schema migration Full data migration
Amazon Aurora PostgreSQL The usage permission on pg_catalog The SELECT permission on the objects to be migrated
ApsaraDB RDS for PostgreSQL The create and usage permissions on the objects to be migrated The owner permission on schemas

Process of full data migration

To avoid data migration failures caused by dependencies between objects, DTS migrates the schemas and data of the source PostgreSQL database in the following order:

  1. Migrate the schemas of tables, views, sequences, functions, user-defined types, rules, domains, operations, and aggregates.
  2. Perform full data migration.
  3. Migrate the schemas of triggers and foreign keys.

Preparation 1: Edit the inbound rule of the Amazon Aurora PostgreSQL instance

  1. Log on to the Amazon Aurora console.
  2. Go to the Basic Information page of the Amazon Aurora PostgreSQL instance.
  3. Select the node that is set to the role of Writer.
  4. In the Connectivity & security section, click the name of the VPC security group that corresponds to the Writer node.
    Security group rules
  5. On the Security groups page, click the Inbound tab in the Security group section. On the Inbound tab, click Edit to add the CIDR blocks of DTS servers in the corresponding region to the inbound rule. For more information, see Add the CIDR blocks of DTS servers to the security settings of on-premises databases.
    Edit the inbound rule of the Amazon RDS for PostgreSQL instance
    Note
    • You only need to add the CIDR blocks of DTS servers that are located in the same region as the destination database. For example, the source database is located in Singapore and the destination database is located in Hangzhou. You only need to add the CIDR blocks of DTS servers that are located in the China (Hangzhou) region.
    • You can add all of the required CIDR blocks to the inbound rule at a time.

Preparation 2: Create a database and schema in the destination RDS instance

Create a database and schema in the destination RDS instance based on the database and schema information of the objects to be migrated. The schema name of the destination database must be the same as that of the source database. For more information, see Create a database on an ApsaraDB RDS for PostgreSQL instance and Appendix: User and schema management.

Procedure

  1. Log on to the DTS console.
  2. In the left-side navigation pane, click Data Migration.
  3. At the top of the Migration Tasks page, select the region where the destination cluster resides.
    Select a region
  4. In the upper-right corner of the page, click Create Migration Task.
  5. Configure the source and destination databases.
    Configure the source and destination databases
    Section Parameter Description
    N/A Task Name DTS automatically generates a task name. We recommend that you specify an informative name for easy identification. You do not need to use a unique task name.
    Source Database Instance Type Select User-Created Database with Public IP Address.
    Instance Region Select the region where the source instance resides. If the instance type is set to User-Created Database with Public IP Address, you do not need to specify the instance region.
    Database Type Select PostgreSQL.
    Hostname or IP Address Enter the endpoint that is used to connect to the Amazon Aurora PostgreSQL instance.
    Note You can find the endpoint on the Basic information page of the Amazon Aurora PostgreSQL instance.
    View the endpoint
    Port Number Enter the service port number of the Amazon Aurora PostgreSQL instance. The default port number is 5432.
    Database Name Enter the name of the source database in the Amazon Aurora PostgreSQL instance.
    Database Account Enter the database account of the Amazon Aurora PostgreSQL instance. For more information about the permissions that are required for the account, see Permissions required for database accounts.
    Database Password Enter the password of the source database account.
    Note After you specify the source database parameters, click Test Connectivity next to Database Password to verify whether the specified parameters are valid. If the specified parameters are valid, the Passed message appears. If the Failed message appears, click Check next to Failed. Modify the source database parameters based on the check results.
    Destination Database Instance Type Select RDS Instance.
    Instance Region Select the region where the destination ApsaraDB RDS for PostgreSQL instance resides.
    RDS Instance ID Select the ID of the destination ApsaraDB RDS for PostgreSQL instance.
    Database Name Enter the name of the destination database in the ApsaraDB RDS for PostgreSQL instance. The name can be different from the name of the source database in the Amazon Aurora PostgreSQL instance.
    Note Before you configure the data migration task, you must create a database and schema in the ApsaraDB RDS for PostgreSQL instance. For more information, see Preparation 2: Create a database and schema in the destination RDS instance.
    Database Account Enter the database account of the destination ApsaraDB RDS for PostgreSQL instance. For more information about the permissions that are required for the account, see Permissions required for database accounts.
    Database Password Enter the password of the destination database account.
    Note After you specify the destination database parameters, click Test Connectivity next to Database Password to verify whether the specified parameters are valid. If the specified parameters are valid, the Passed message appears. If the Failed message appears, click Check next to Failed. Modify the destination database parameters based on the check results.
  6. In the lower-right corner of the page, click Set Whitelist and Next.
    Note DTS adds the CIDR blocks of DTS servers to the whitelist of the ApsaraDB RDS for MySQL instance. This ensures that DTS servers can connect to the ApsaraDB RDS for MySQL instance.
  7. Select the migration types and the objects to be migrated.
    Select the migration types and the objects to be migrated
    Parameter Description
    Migration Types Select Schema Migration and Full Data Migration. In this data migration task, Incremental Data Migration is not supported.
    Note To ensure data consistency, we recommend that you do not write data to the Amazon Aurora PostgreSQL instance during data migration.
    Objects

    Select objects from the Available section and click the Right arrow icon to move the objects to the Selected section.

    Note
    • You can select columns, tables, or databases as the objects to be migrated.
    • After an object is migrated to the destination database, the name of the object remains unchanged. You can use the object name mapping feature to change the names of the objects that are migrated to the destination database. For more information, see Object name mapping.
    • If you use the object name mapping feature on an object, other objects that are dependent on the object may fail to be migrated.
  8. In the lower-right corner of the page, click Precheck.
    Notice
    • Before you can start the data migration task, a precheck is performed. A data migration task can be started only if it passes the precheck.
    • If the task fails to pass the precheck, click the Info icon icon next to each failed item to view details. Troubleshoot the issues based on the causes and perform a precheck again.
  9. After the task passes the precheck, click Next.
  10. In the Confirm Settings dialog box, specify the Channel Specification parameter and select Data Transmission Service (Pay-As-You-Go) Service Terms.
  11. Click Buy and Start to start the data migration task.
    Note Do not manually stop a migration task. Otherwise, data migrated to the destination database will be incomplete. Wait until the data migration task stops when it is complete.
    Full data migration
  12. Switch your workloads to the ApsaraDB RDS for PostgreSQL instance.