FAQ

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

What versions of OMS Community Edition can be upgraded to V4.2.8?

Only OMS Community Edition V4.2.0 to V4.2.7 can be upgraded to OMS Community Edition V4.2.8.

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. If the upgrade fails, you can promptly start the container of OMS Community Edition of the original version.

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 component. The prerequisite for automatic Store component creation is that the number of Store components under the subtopic does not exceed the value of the subtopicStoreNumberThreshold parameter of ha.config. By default, the number of Store components under a subtopic is 5.

1. Log in to the console of OMS Community Edition.

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.