Migrate the data of an ApsaraDB RDS for PostgreSQL instance from the ApsaraDB RDS for PostgreSQL console

Impact

The migration causes a transient connection error. We recommend that you perform the migration during off-peak hours.

Precautions

Each migration task is used to migrate the data of only a single database. If you want to migrate the data of more than one database, create a migration task for each of the databases.

Migration process

1. Configure the source RDS instance
2. Configure the destination RDS instance
3. Use DTS to migrate data
4. Switch over your workloads to the destination RDS instance

Configure the source RDS instance

1. Log on to the ApsaraDB RDS for PostgreSQL console.
2. In the top navigation bar, select the region where the source RDS instance resides.
3. Find the source RDS instance and click its ID.
4. On the Basic Information page, click Apply for Public Endpoint. In the message that appears, click OK.
   Note You can view the public endpoint only after an IP address whitelist is configured. We recommend that you choose Data Security > Whitelist Configuration in the left-side navigation pane and then enter 0.0.0.0/0 in the Allowed IP Addresses field for the IP address whitelist labeled default. This allows all devices to access the source RDS instance.

Configure the destination RDS instance

1. Log on to the ApsaraDB RDS console and create an RDS instance that runs PostgreSQL 11. This RDS instance is the destination RDS instance. For more information, see Create an ApsaraDB RDS for PostgreSQL instance.
2. Create a privileged account on the destination RDS instance. For more information, see Create an account on an ApsaraDB RDS for PostgreSQL instance.
3. Create databases on the destination RDS instance. We recommend that each database on the source RDS instance has a counterpart with an identical name on the destination RDS instance. For more information, see Create a database on an ApsaraDB RDS for PostgreSQL instance.

Use DTS to migrate data

For more information about the precautions, see Migrate incremental data from a user-created PostgreSQL database (version 10.1 to 12) to an ApsaraDB RDS for PostgreSQL instance.

1. Log on to the DTS console.
2. In the left-side navigation pane, click Data Migration. In the upper-right corner of the page, click Create Migration Task.
3. Configure the following parameters.

   Section	Parameter	Description
   None	Task Name	Enter the name that Alibaba Cloud Data Transmission Service (DTS) generates for the migration task. 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 to which the source RDS instance belongs.
   	Database Type	Select PostgreSQL.
   	Hostname or IP Address	Enter the public endpoint of the source RDS instance.
   	Port Number	Enter the port number that is associated with the public endpoint of the source RDS instance.
   	Database Name	Enter the name of the source database whose data you want to migrate from the source RDS instance. Note Each migration task is used to migrate the data of only a single database. If you want to migrate the data of more than one database, create a migration task for each of the databases.
   	Database Account	Enter the username of the account that you want to use to log on to the source RDS instance. We recommend that you use the privileged account or a standard account that has read and write permissions on the source database.
   	Database Password	Enter the password of the account that you want to use to log on to the source RDS instance. 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 to which the destination RDS instance belongs.
   	RDS Instance ID	Select the ID of the destination RDS instance.
   	Database Name	Enter the name of the destination database to which you want to migrate data on the destination RDS instance.
   	Database Account	Enter the username of the account that you want to use to log on to the destination RDS instance. We recommend that you use the privileged account or a standard account that has read and write permissions on the destination database.
   	Database Password	Enter the password of the account that you want to use to log on to the source RDS instance. Note After you specify the destination database parameters, click Test Connectivity next to Database Password to verify whether the 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.

4. In the lower-right corner of the page, click Set Whitelist and Next.
5. Select migration types and objects.

   Configuration item	Description
   Migration types	Select all of the migration types. The supported migration types are Schema Migration, Full Data Migration, and Incremental Data Migration.
   Migration objects	Select objects in the Available section and click the icon to move them to the Selected section.

6. In the lower-right corner of the page, click Precheck.
   Note

   • A precheck is performed before the migration task starts. The migration task can start only after it passes the precheck.
   • If the migration task fails the precheck, click the icon next to each failed check item to view details about the failure. After all of the identified failures are rectified, you must perform a precheck again.
7. After the task passes the precheck, click Next.
8. In the Confirm Settings dialog box, specify Channel Specification, read and select Data Transmission Service (Pay-As-You-Go) Service Terms, and then click Buy and Start.

Switch over your workloads to the destination RDS instance

1. Wait until the migration task enters the Incremental Data Migration phase. The state of the incremental data migration phase must show The migration task is not delayed or a delay shorter than 5 seconds.
   
2. Stop your workloads and forbid new writes to the source database.
3. Log on to the source database and run the following command to verify that no new sessions are created to write data:

   select * from pg_stat_activity;

4. Wait until the state of the Incremental Data Migration phase changes to The migration task is not delayed and stays in that state for one minute or longer. Then, manually terminate the migration task.
   
5. On the Basic Information page for the source RDS instance, click Lock Instance to Read-only. In the message that appears, click OK.
6. Update the endpoints of the destination RDS instance to your application.

The data migration is complete. Observe the performance of the source RDS instance for a period of time. If your workloads run properly on the destination RDS instance, we recommend that you release or submit a ticket to unsubscribe from the source RDS instance..