OceanBase clusters can be upgraded by using upgrade scripts. The upgrade process is transparent to applications, so you do not need to stop or suspend your applications or services to perform an upgrade. An OceanBase cluster is upgraded zone by zone. During the upgrade, the system will perform an active leader switchover between zones and redirect the business in the zone to be upgraded to other zones.
This topic describes the upgrade limitations, considerations, and paths of OceanBase Database.
Notice
OceanBase Database V4.x does not support in-place upgrades from versions earlier than V4.0.0.
Limitations
There are limitations to consider when upgrading an OceanBase cluster:
- DDL is prohibited: DDL is prohibited during some stages of the upgrade. It will be automatically enabled after the upgrade is completed.
major freezeis prohibited: The merge is prohibited during the upgrade from some versions. It will be automatically enabled after the upgrade is completed.- Replication and load balancing are prohibited: The cluster version upgrade prohibits replication and load balancing.
- Physical backup and restore are prohibited: Physical baseline backup (log archive) and physical restore are prohibited during the upgrade. However, ODP is supported.
- Creating tenants is prohibited.
Notice
If the OceanBase cluster is associated with the arbitration service, make sure to upgrade the arbitration service version before upgrading the OceanBase cluster version. For more information, see Upgrade the arbitration service.
You can query the oceanbase.DBA_OB_ARBITRATION_SERVICE system view in the sys tenant to check whether the OceanBase cluster is associated with the arbitration service.
Considerations
Consider the following points when upgrading an OceanBase cluster:
Log archive is suspended during the upgrade from OceanBase Database V4.0 to V4.1.
Contact a technical specialist if the upgrade requires the
ADD SERVER/DELETE SERVERoperation.You cannot directly upgrade to a transitional version. Refer to the upgrade version sequence in the
oceanbase_upgrade_dep.ymlfile.The upgrade script must be executed directly on the observer node where the root service process resides. It cannot be connected to through OceanBase Database Proxy (ODP).
Back up the following parameters before the upgrade, as they may be modified during the upgrade:
Upgrade procedure
The upgrade scripts in OceanBase Database V4.x rely only on the Python scripts in the target RPM package. In other words, if the target version is V4.1.0 or later, only one upgrade process is available, and it requires only the OceanBase RPM package of the target version. After decompressing the OceanBase RPM package, you will find the oceanbase_upgrade_dep.yml file, which records the version upgrade topology of OceanBase Database.
For more information about the upgrade process, see Step 2: Confirm the upgrade procedure in Upgrade an OceanBase cluster.
Upgrade notes
- Online upgrade from OceanBase Database V4.1.0 to OceanBase Database V4.2.0 Beta is supported.
- An online upgrade from OceanBase Database V3.x to OceanBase Database V4.2.0 is not supported.
- You can use OMS to migrate data from OceanBase Database V3.x to OceanBase Database V4.2.0.