ApsaraDB RDS:Major engine version upgrade and cross-version upgrade of an ApsaraDB RDS for PostgreSQL instance

Background information

The PostgreSQL community releases a major engine version on a regular basis. Each new major engine version includes improvements in terms of functionality and performance compared with previous major engine versions. The PostgreSQL community will stop providing technical support for earlier major engine versions in phases, which increases the probability of performance risks and security risks of these versions. ApsaraDB RDS for PostgreSQL provides the major engine version upgrade feature. This feature enables you to use the performance and functionality delivered by new major engine versions and mitigates the risks that may be caused by an upgrade.

Procedure

1. Perform an upgrade check.

   Check whether the original RDS instance supports major engine version upgrades. Then, view the check report that is generated. If the check result in the upgrade check report is Fail, you cannot upgrade the major engine version. You can upgrade the major engine version only after the upgrade check is passed.

2. Optional. Perform a compatibility test.

   After you upgrade the major engine version of your RDS instance, the new major engine version may be incompatible with your workloads. Therefore, we recommend that you use the No cutting configuration method to test whether the new major engine version is compatible with your workloads before you perform the upgrade.

3. Upgrade the major engine version.

   Upgrade the major engine version of the original RDS instance. Select the Cutover configuration method after the new major engine version passes the compatibility test.

Highlights

• Cross-version upgrade: You can upgrade the major engine version of the original RDS instance to a later version. For example, you can upgrade the major engine version from PostgreSQL 10 to PostgreSQL 13.

• Upgrade trial: You can use the No cutting configuration method to verify the feasibility of an upgrade without interruptions to your workloads on the original RDS instance.

• Smooth upgrade:

  • No application modification: You can use the Cutover configuration method to perform an upgrade. After the switchover is complete, you do not need to modify the endpoint configuration on your application. Your application automatically connects to the new RDS instance.

    Note

    If you use the Cutover configuration method to upgrade the major engine version of your original RDS instance, the virtual IP address (VIP) of the new RDS instance is different from that of the original RDS instance. If you configured the VIP of the original RDS instance on your application, you must change the VIP of the original RDS instance to the VIP of the new RDS instance on your application. We recommend that you configure the endpoint of the original RDS instance on your application. For more information about how to obtain the endpoint of an RDS instance, see View and change the endpoints and port numbers of an ApsaraDB RDS for PostgreSQL instance.

  • No downtime: An upgrade does not cause downtime on the original RDS instance. This mitigates the risks of service interruptions. However, the original RDS instance processes only read requests for a few minutes during the upgrade. In addition, the system performs the upgrade by using instance cloning. The original RDS instance is not affected even if the upgrade fails.

  • Reserved instance configuration:

    • The new RDS instance carries over the IP address whitelists, parameter settings, and extensions of the original RDS instance. However, this does not apply to the extensions or parameters that are not supported in the new major engine version.

    • If the original RDS instance supports fully encrypted databases, the new RDS instance also supports fully encrypted databases and carries over the key that is used on the original RDS instance to encrypt data. For more information, see Create a fully encrypted database on an ApsaraDB RDS for PostgreSQL instance.

Billing rules

• The billing method of the new RDS instance may be changed.

  Billing method of the original instance	Billing method of the new instance
  Subscription/Pay-as-you-go	Pay-as-you-go
  Serverless	Serverless

• After you verify that your workloads run as expected on the new RDS instance, change the billing method of the new RDS instance to subscription and release or unsubscribe from the original RDS instance. For more information, see Switch an ApsaraDB RDS for PostgreSQL instance from pay-as-you-go to subscription and Release or unsubscribe from an ApsaraDB RDS for PostgreSQL instance.

  • If you release a subscription RDS instance before it expires, you are eligible for a refund. However, the refund will be less than the original purchase amount.

  • If you purchased your original RDS instance at discount rates, the new RDS instance does not carry over the discounts that are offered for the original RDS instance. To determine whether to upgrade the major engine version of the original RDS instance, you can log on to the Alibaba Cloud Management Console and go to the Unsubscribe page to check the refund amount.

  • The refund amount and the arrival time of the refund are displayed in your bills. The refund does not arrive immediately.

Prerequisites

The original RDS instance must meet the following requirements:

• The original RDS instance runs PostgreSQL 15 or earlier.

  Note

  You can directly upgrade the major engine version of your RDS instance from PostgreSQL 9.4 to PostgreSQL 10, PostgreSQL 11, PostgreSQL 12, PostgreSQL 13, and PostgreSQL 14. If you want to upgrade the major engine version from PostgreSQL 9.4 to PostgreSQL 15, you must upgrade the major engine version to PostgreSQL 10, PostgreSQL 11, PostgreSQL 12, PostgreSQL 13, or PostgreSQL 14. Then, you can upgrade the major engine version to PostgreSQL 15 or later.

• The original RDS instance runs RDS High-availability Edition or RDS Basic Edition. For more information, see RDS High-availability Edition and RDS Basic Edition.

• The original RDS instance resides in a virtual private cloud (VPC).

  If the original RDS instance resides in the classic network, you must change the network type of the original RDS instance to VPC before you perform an upgrade. When you change the network type, clear Reserve original classic network endpoint. For more information about how to view or change the network type of an RDS instance, see Change the network type of an ApsaraDB RDS for PostgreSQL instance.

  Note

  If you select Reserve original classic network endpoint, you must wait until the retention period of the endpoint ends before you can start the upgrade task.

• The original RDS instance cannot be a read-only instance and cannot be created in a dedicated cluster. For more information, see Overview of read-only ApsaraDB RDS for PostgreSQL instances and What is ApsaraDB for MyBase?

• The ID of the original RDS instance does not start with pg-cn.

Impact

An upgrade has the following impacts:

• If you select the Cutover configuration method, the system needs to switch your workloads over to a new RDS instance during the upgrade. The original RDS instance processes only read requests and a transient connection that lasts a few minutes occurs during the switchover. We recommend that you perform an upgrade during off-peak hours. If you select the No cutting configuration method, the original RDS instance is not affected.

  Note

  • The period of time during which the original RDS instance processes only read requests varies based on the number of database objects. If a large number of database objects exist in the original RDS instance, the original RDS instance processes only read requests for a long period of time. If millions of database objects exist, the original RDS instance may process only read requests for dozens of minutes or several hours. You can execute the SELECT count(1) FROM pg_class; statement to query the number of database objects in the original RDS instance.

  • The duration of a transient connection varies based on the interval at which Domain Name System (DNS) caches are refreshed. You can switch to a different vSwitch and estimate the intervals to refresh DNS caches on your database client based on the duration of the transient connection. For more information, see Switch an ApsaraDB RDS for PostgreSQL instance to a different vSwitch.

  • The period of time that is required to complete the upgrade varies based on the data volume and the number of database objects in the original RDS instance. If a large amount of data and a large number of database objects exist in the original RDS instance, the upgrade requires a long period to complete.

• If the original RDS instance uses a parameter that is not supported by the new major engine version, the parameter is deleted from the new RDS instance. If the value of a parameter in the previous major engine version is not within the value range that is supported in the new major engine version, the system sets the parameter to the default value that is specified in the new major engine version.

• The new RDS instance does not carry over the name, tags, alert rules, and backup data of the original RDS instance. For more information, see Add tags to ApsaraDB RDS for PostgreSQL instances, Configure an alert rule on an ApsaraDB RDS for PostgreSQL instance, and Back up an ApsaraDB RDS for PostgreSQL instance.

• If the original RDS instance serves as the source RDS instance or destination RDS instance of a migration task that is created in the Data Transmission Service (DTS) console, you must re-create the migration task after you perform an upgrade. For more information about how to create a migration task in the DTS console, see What is DTS?

• After an upgrade is complete, the read-only RDS instances and logical replication slots that you created in the original RDS instance remain attached to the original RDS instance rather than the new RDS instance. You must create read-only RDS instances and logical replication slots on the new RDS instance after the upgrade.

• If a read-only RDS instance is attached to the original RDS instance, you must perform the following operations before and after you perform an upgrade:

  If a read-only RDS instance is attached to the original RDS instance, you must perform the following operations before and after you perform an upgrade:

  1. Change the endpoint of the read-only RDS instance to the endpoint of the original RDS instance on your application.

     Note

     For service stability purposes, we recommend that you modify the endpoint configuration on your application during off-peak hours.

  2. Delete the read-only RDS instance.

  3. Upgrade the major engine version. For more information, see Procedure.

  4. After the upgrade is complete, create a read-only RDS instance on the new RDS instance. For more information, see Create a read-only ApsaraDB RDS for PostgreSQL instance.

  5. Change the endpoint of the original RDS instance to the endpoint of the new read-only RDS instance on your application.

• When you upgrade the major engine version, the latest minor engine version is required. This may cause extension compatibility issues. For more information, see Update the minor engine version.

• The period of time that is required to complete the upgrade varies based on the data volume of your RDS instance. You can view the upgrade progress on the Task Center page in the ApsaraDB RDS console. For more information, see Use Task Center.

• After you upgrade the major engine version of your RDS instance, you cannot roll back the upgrade. If you want to use an early major engine version, you must create another RDS instance that runs the required major engine version and use Data Transmission Service (DTS) to migrate the data of the upgraded RDS instance to the newly created RDS instance.

Procedure

1. If a read-only RDS instance is attached to the original RDS instance, perform the following steps before you perform an upgrade:

   1. Change the endpoint of the read-only RDS instance to the endpoint of the original RDS instance on your application.

      Note

      For service stability purposes, we recommend that you modify the endpoint configuration on your application during off-peak hours.

   2. Delete the read-only RDS instance.

2. Go to the Major Version Upgrade page.

   1. Go to the Instances page. In the top navigation bar, select the region in which the RDS instance resides. Then, find the RDS instance and click the ID of the instance.

   2. In the left-side navigation pane, click Major Version Upgrade.

      Note

      If you do not find Major Version Upgrade in the ApsaraDB RDS console, check whether your RDS instance meets all requirements that are described in Prerequisites.

3. On the Upgrade Check tab, select the new major engine version and click Create upgrade check report. This process requires a few minutes.

   Note

   • Make sure that your RDS instance passes the upgrade check. Then, proceed with the subsequent steps.

   • If you execute the CREATE EXTENSION statement on your RDS instance after the RDS instance passes the upgrade check, you must perform an upgrade check again.

   If the upgrade check report indicates that your RDS instance fails the upgrade check, you can click View Information in the Report Content column to view the details about the failure in the report. For more information, see Introduction to the check report of a major engine version upgrade to an ApsaraDB RDS for PostgreSQL instance.

4. Click the Upgrade Instance tab. On the tab that appears, read the warning that is displayed, configure the Select upgrade version, and then click Continue to create upgrade instance.

5. In the message that appears, read the tips and click OK. Then, configure parameters. The following table describes only the crucial parameters.

   Parameter	Description
   Storage type	Select the storage type that is used for the new RDS instance. The major engine version upgrade feature is based on snapshots for cloud disks. You can select one of the following storage types: ESSD PL1 ESSD PL2 ESSD PL3
   Current Zone	Specify the zones and vSwitches of the new RDS instance and its secondary RDS instance. The zones that you specify can be different from the zones of the original RDS instance.
   The Available Zone
   Primary Instance Switch
   Standby Instance Switch
   Cutover configuration	The system allows you to create an RDS instance for data migration. Specify whether to enable the system to automatically switch your workloads over to the new RDS instance after data migration is complete. No cutting: The system does not automatically switch your workloads over to the new RDS instance. Before the first time you perform an upgrade, we recommend that you select the No cutting configuration method to test whether the new major engine version is compatible with your workloads. If the new major engine version passes the compatibility test, you can release the new RDS instance. Then, you can select the Cutover configuration method to perform the upgrade. For more information, see Release or unsubscribe from an ApsaraDB RDS for PostgreSQL instance and Procedure. Note The data migration does not interrupt your workloads on the original RDS instance. If you select the No cutting configuration method, you must change the endpoint of the original RDS instance to the endpoint of the new RDS instance on your application after the data is migrated to the new RDS instance. For more information about how to view the endpoint of an RDS instance, see View and change the endpoints and port numbers of an ApsaraDB RDS for PostgreSQL instance. Cutover: The system automatically switches your workloads over to the new RDS instance. After the switchover is complete, you do not need to update the endpoint configuration on your application. Your application automatically connects to the new RDS instance. This configuration method is used to perform an upgrade after you verify that the new major engine version is compatible with your workloads. Note After the switchover is complete, you cannot roll your workloads back to the original RDS instance. Proceed with caution. During the switchover, the original RDS instance processes only read requests. We recommend that you perform the switchover during off-peak hours. If the original RDS instance has read-only RDS instances, you cannot select the Cutover configuration method. In this case, you can upgrade the major engine version of the original RDS instance only by using the No cutting configuration method. In addition, the read-only RDS instances that are attached to the original RDS instance are not cloned. After the upgrade is complete, you must create read-only RDS instances that run the new major engine version for the new RDS instance. For more information, see Create a read-only ApsaraDB RDS for PostgreSQL instance.
   Cutover time	Specify the point in time when the system switches your workloads over to the new RDS instance after the data is migrated to the new RDS instance. immediately: After the data is migrated to the new RDS instance, the system immediately switches your workloads over to the new RDS instance. Instance operation and maintenance time: The system switches your workloads over to the new RDS instance during the maintenance window that you specified. For more information, see Set the maintenance window of an ApsaraDB RDS for PostgreSQL instance. Note This parameter is available only when you set the Cutover configuration parameter to Cutover.
   Statistical information collection mode	Specify the point in time at which the system collects the statistics of the new RDS instance. Collection before cutting: This option ensures the stability of your database service. If the original RDS instance contains a large amount of data, the upgrade may require a long period of time. Collection after cutting: This option accelerates the upgrade process. If you access tables for which no statistics are generated, the query plans that you specify may be inaccurately executed. In addition, your database service may be unavailable during peak hours. Note If you select the No cutting configuration method, the Collection before cutting option specifies that the system collects the statistics of the new RDS instance before the new RDS instance starts to process read and write requests, and the Collection after cutting option specifies that the system collects the statistics of the new RDS instance after the new RDS instance starts to process read and write requests.
   Storage space	Specify the storage capacity of the new RDS instance. If the original RDS instance uses local SSDs, you can reduce the storage capacity of the RDS instance when you upgrade the major engine version of the RDS instance. The minimum value that you specify for the Storage space parameter must meet the following requirements: The minimum value is determined by the smaller one between the following values: The used storage of the original RDS instance multiplied by 120% in GB. If the result is not a multiple of 5, the obtained value is rounded up to a multiple of 5. Note You can view the used storage of the original RDS instance in the Disk Storage(MB) section on the Monitoring and Alerting page. For more information, see View the Enhanced Monitoring metrics of an ApsaraDB RDS for PostgreSQL instance. The storage capacity of the original RDS instance. The minimum value is greater than or equal to the minimum storage capacity of an ESSD. If the minimum value is smaller than the minimum storage capacity of an ESSD, you must use the minimum storage capacity of the ESSD as the minimum value. The following list provides the minimum storage capacities of ESSDs of different performance levels (PLs). ESSD PL1: 20 GB ESSD PL2: 500 GB ESSD PL3: 1,500 GB Note Examples: The storage capacity of the original RDS instance is 100 GB, 70 GB of storage is used, and ESSD PL1 is selected as the storage type when you upgrade the major engine version of the RDS instance. Calculation method: 70 × 120% = 84, rounded up to 85. The minimum value for the Storage space parameter is 85 GB. The storage capacity of the original RDS instance is 700 GB, 350 GB of storage is used, and ESSD PL2 is selected as the storage type when you upgrade the major engine version of the RDS instance. Calculation method: 350 × 120% = 420. The obtained value 420 GB is smaller than 500 GB that is supported by an ESSD of PL2. The minimum value for the Storage space parameter is 500 GB.
   Instance specification	Specify the instance type of the new RDS instance. For more information about the instance types that are supported, see Primary ApsaraDB RDS instance types.

6. Click Create now.

   The status of the original RDS instance changes to Migration in Progress. In addition, you can find a new RDS instance on the Instances page. The new RDS instance is in the Creating state. After the new RDS instance is created and the upgrade is complete, the statuses of the original RDS instance and new RDS instance change to Running. The time that is required for the upgrade varies based on the amount of data.

   Note

   • After you create an upgrade task, you cannot modify or delete the task.

   • If the original RDS instance is in the Migrating state, you cannot perform O&M operations on the RDS instance. For example, you cannot modify the parameters of the RDS instance and restart or release the RDS instance.

   • After you click Create now, if the message Insufficient resources appears, change the value of the The Available Zone parameter.

7. If a read-only RDS instance is attached to the original RDS instance and you deleted the read-only RDS instance in Step 1, perform the following steps after the upgrade:

   1. Create a read-only RDS instance for the new RDS instance. For more information, see Create a read-only ApsaraDB RDS for PostgreSQL instance.

   2. Change the endpoint of the original RDS instance to the endpoint of the new read-only RDS instance on your application. For more information, see Step 1.

What to do next

1. After you verify that your workloads run as expected on the new RDS instance, change the billing method of the new RDS instance to subscription. For more information, see Switch an ApsaraDB RDS for PostgreSQL instance from pay-as-you-go to subscription.

2. Release the original RDS instance. For more information, see Release or unsubscribe from an ApsaraDB RDS for PostgreSQL instance.

   Note

   • If you release a subscription RDS instance before it expires, you are eligible for a refund. However, the refund will be less than the original purchase amount.

   • If you purchased your original RDS instance at discount rates, the new RDS instance does not carry over the discounts that are offered for the original RDS instance. You can log on to the Alibaba Cloud Management Console and go to the Unsubscribe page to check the refund amount.

   • The refund amount and the arrival time of the refund are displayed in your bills. The refund does not arrive immediately.

3. Create read-only RDS instances for the new RDS instance based on your business requirements because the new RDS instance does not carry over the read-only RDS instances of the original RDS instance. For more information, see Create a read-only ApsaraDB RDS for PostgreSQL instance.

References

• Introduction to the check report of a major engine version upgrade for an ApsaraDB RDS for PostgreSQL instance

• View and change the endpoints and port numbers of an ApsaraDB RDS for PostgreSQL instance

• Primary ApsaraDB RDS instance types

• Release or unsubscribe from an ApsaraDB RDS for PostgreSQL instance

• Change the billing method of an ApsaraDB RDS for MySQL instance from pay-as-you-go to subscription

• You can also call API operations to upgrade the major engine version of your RDS instance. The following table describes the related API operations:

  Operation	Description
  UpgradeDBInstanceMajorVersionPrecheck	Checks the compatibility between a new major engine version and workloads on an ApsaraDB RDS for PostgreSQL instance before an upgrade.
  DescribeUpgradeMajorVersionPrecheckTask	Queries the check report for the major engine version upgrade of an ApsaraDB RDS for PostgreSQL instance.
  UpgradeDBInstanceMajorVersion	Upgrades the major engine version of an ApsaraDB RDS for PostgreSQL instance.
  DescribeUpgradeMajorVersionTask	Queries the tasks that are created to upgrade the major engine version of an ApsaraDB RDS for PostgreSQL instance.

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