FAQ

This topic summarizes the questions that are frequently asked during the upgrade of OceanBase Migration Service (OMS).

Which versions of OMS can be upgraded to V4.2.5?

OMS V3.2.1 and later can be directly upgraded to V4.2.5. OMS of a version earlier than V3.2.1 must be first upgraded to V3.2.1.

Must I back up the original database before the upgrade?

We recommend that you back up the original database before you start the upgrade. The backup of the original database is a fail-safe measure in the upgrade process. Once the upgrade fails, you can start the original OMS container.

If you do not back up the original database, make sure that the name of the new database is the same as that of the original database. Note that in this case, you cannot roll back to the original database if the upgrade fails.

How can I control the interval for pulling data from the Store component?

You can enable high availability (HA) to automatically create a new store. The prerequisite for automatic store creation is that the number of stores under the subtopic does not exceed the value of subtopicStoreNumberThreshold in the ha.config system parameter. By default, the number of stores under a subtopic is 5.

1. Log in to the OMS console.

2. In the left-side navigation pane, choose System Management > System Parameters.

3. On the System Parameters page, find ha.config and click the edit icon in the Value column.

4. In the Modify Value dialog box, set enable to true to enable HA.

5. Set the perceiveStoreClientCheckpoint parameter to true to enable data pulling from the Store component for the downstream component.

   If you set perceiveStoreClientCheckpoint to false, you need to set the refetchStoreIntervalMin parameter to the desired value. This parameter specifies the time interval, in minutes, for pulling data from the Store component.

   For example, if the tasks monitored in the original container are all executed in real time, you plan to stop the original container at 4:00 pm, and the upgrade is expected to complete at 5:00 pm, we recommend that you set the refetchStoreIntervalMin parameter to 90 minutes. This interval is the sum of a 60-minute period (between the container stop time and the upgrade end time) and a 30-minute redundant period (based on the business traffic).

If I modify the parameters of some processes before the upgrade, do the parameters exist after the upgrade?

• If you modify the parameters of the Full-Import, Incr-Sync, or Full-Verification component, the modified parameters still exist after the upgrade.

• If you modify the parameters of the Store component, such as an allowlist-related parameter, the subtopic configuration is updated accordingly, and the modified parameters still exist after the upgrade succeeds.

What do I do to resolve configuration compatibility issues when I upgrade OMS V3.2.1 or V3.2.2 to V4.2.5?

In scenarios involving DDL synchronization, if you do not add the dbType parameter before the upgrade, the task cannot run. You can choose one of the following methods to fix the issue after the upgrade. In scenarios not involving DDL synchronization, if the source database is an OceanBase data source, the value of dbType is OB_MySQL by default.

Method 1: Modify the configuration

1. Log in to the OMS console.

2. In the left-side navigation pane, choose OPS & Monitoring > Components > Incr-Sync.

3. On the Incr-Sync tab, click Update in the Actions column of the Incr-Sync component.

4. In the Update Configuration dialog box, hover the pointer over the blank area on the right side of the source field and click + to add the dbType parameter.

   Notice

   If the checkpoint parameter is not specified, you need to specify the corresponding information.

5. Click OK.

If only one type of source database exists on the server, you can perform the following operations:

1. Click Batch O&M in the upper-right corner of the Incr-Sync tab.

2. In the Batch O&M dialog box, click Update.

3. After you select IP and specify the IP address, hover the pointer over the blank area on the right side of the source field in the Configuration section and click + to add the dbType parameter.

   

4. After the configuration is completed, click Submit.

Method 2: Re-create the task

1. Log in to the OMS console.

2. In the left-side navigation pane, click Data Synchronization.

3. On the Synchronization Tasks page, click Clone next to the name of the target task.

4. Configure information of the cloned task and change the synchronization start timestamp to a timestamp before the upgrade.

5. After the configuration is completed, start the data synchronization task and make sure that it runs normally.

6. Delete the previous data synchronization task.

What do I do to avoid impact on data synchronization tasks when I upgrade OMS?

Symptom: When you upgrade OMS, you must re-create a docker. As a result, all tasks running in the OMS container are stopped for a period of time, which affects data synchronization tasks.

Solution:

1. Select a server.

2. Change the status of the server to OFFLINE.

3. Migrate the tasks on the server to other servers.

4. Upgrade OMS on the server.

5. Change the status of the server to ONLINE.