This topic describes the upgrade process, considerations, limitations, and impact when upgrading an OceanBase cluster.
OceanBase Database allows you to upgrade a cluster by using the upgrade script. The entire upgrade process is transparent to the applications and does not interrupt the write operations or services on the application side. OceanBase clusters are upgraded zone by zone. During the upgrade, partition leaders are switched between zones, and the business traffic from the zone being upgraded will be redirected to other zones.
Notice
At present, OceanBase Database cannot be upgraded from a version earlier than V4.0.0.0 to V4.x.
Upgrade process
The upgrade script depends only on the Python script related to the RPM package of the target version. To be specific, if the target version is V4.1.0 or later, only one upgrade process exists and only the RPM package of the target version is required. After the RPM package of OceanBase Database is decompressed, you can obtain the oceanbase_upgrade_dep.yml file, which records the upgrade topology of OceanBase Database.
For more information about how to check the upgrade process, see Step 2: Confirm the upgrade process in Upgrade an OceanBase cluster.
Considerations
When you upgrade an OceanBase cluster, note that:
If the
ADD SERVER/DELETE SERVERoperation needs to be performed during the upgrade, contact OceanBase Technical Support.If you want to upgrade a transitional version, it is necessary to follow a specific version sequence for the upgrade instead of directly skipping the transitional version and upgrading to the next major version.
To execute the upgrade script, you must connect to RootService in the sys tenant directly instead of by using an OceanBase Database Proxy (ODP).
The following parameters may be modified during the upgrade. Therefore, back up these parameters before the upgrade.
Limitations
Pay attention to the following limitations when you upgrade an OceanBase cluster:
DDL is disabled in some phases of the upgrade and is automatically enabled after the upgrade.
Major freezes are disabled during the upgrade between some versions and are automatically enabled after the upgrade.
Migration, replication, and load balancing are disabled during the upgrade between some versions.
During the upgrade of a cluster, physical baseline backup and physical recovery are not allowed, but log archiving is not interrupted.
Notice
During the upgrade of OceanBase Database from V4.0 to V4.1, log archiving is interrupted.
Switchover and failover are not allowed during the upgrade.
Tenant creation is not allowed.
Notice
If the OceanBase cluster is associated with the arbitration service, you must upgrade the arbitration service before you upgrade the OceanBase cluster. For more information about how to upgrade the arbitration service, see Upgrade the arbitration service.
You can query the oceanbase.DBA_OB_ARBITRATION_SERVICE view of the sys tenant to check whether the current OceanBase cluster is associated with the arbitration service.
Upgrade impact
Pay attention to the following impact when you upgrade an OceanBase cluster:
The partition leader is switched from one zone to another during the upgrade, which increases the response time (RT) a little bit.
The leader-follower switchover during the upgrade can affect your business. Transactions that exceed 100 ms are terminated.