Help Center> GaussDB> Service Overview> GaussDB Constraints
Updated on 2024-01-26 GMT+08:00

GaussDB Constraints

To ensure the stability and security of GaussDB, certain constraints are put in place for access or permissions control. Table 1 describes such constraints.

There is no SLA commitment, so GaussDB single-replica instances cannot be used in production environments. For function constraints of single-replicas, see Table 2.

Table 1 Function constraints

Function

Constraints

Database access

  • To access a GaussDB instance that is not publicly accessible, the instance must be in the same VPC subnet as the ECSs associated with the instance.
  • The ECSs must be allowed by the security group to access the GaussDB instance.

    If a GaussDB instance and the ECSs belong to different security groups, no communication between them is established by default. To allow it, you must add an inbound rule to the GaussDB security group.

  • The default port number of the GaussDB instance is 8000.
  • The database port can be set when a DB instance is created and can be changed after the DB instance is created.

Deployment

ECSs where DB instances are deployed are not directly visible to you. You can only access the DB instances through IP addresses and database ports.

Database root permissions

Only the root user permissions are available on the instance creation page.

NOTE:

After August 30, 2022, the root user of newly created instances and upgraded existing instances has the sysadmin permission. To upgrade your existing instance, contact customer service.

If your existing instances are not upgraded, the root user only has the following permissions: createrole, createdb, and monadmin. The root user has fewer permissions than the administrator. When some SQL syntax or functions, such as create tablespace, are executed, an error message is displayed, indicating that the permissions are insufficient.

GaussDB instance reboot

GaussDB DB instances cannot be rebooted through commands. They must be rebooted on the management console.

GaussDB backup files

GaussDB backup files are stored in OBS buckets and are not visible to you.

Specification changes

  • By default, the specifications cannot be reduced. If you need to reduce the specifications, contact Huawei Cloud customer service.
  • Before you change the instance specifications, ensure that the instance is available. If the instance or node is abnormal, or the storage space is full, you cannot perform this operation.
  • During the specification change for HA (1 primary + 2 standby) instances, a primary/standby failover is triggered. During the failover, services are interrupted for about 1 minute.
  • For a single-replica instance, changing instance specifications will reboot the instance and interrupt services for 5 to 10 minutes.
  • After you change the CPU/memory specifications of an instance, the instance will be rebooted and services will be interrupted. You should select off-peak hours to perform the capacity expansion operations. After the instance is restarted, the cache in the memory is automatically released. Therefore, restart the instance during off-peak hours.

Failover

For primary/standby instances, services are unavailable for about 10 seconds when the primary node is being switched to the standby node.

Data restoration

To prevent data loss, you are advised to back up key data before data restoration.

Storage space

If the storage space of the DB instance is full, data cannot be written to databases. You are advised to periodically check the storage space.

Performance tuning

Performance tuning may need to reboot the instance and interrupt services.

Table 2 Function constraints of single-replica primary/standby instances

Function

Supported by Versions Earlier Than 3.0

Supported by 3.0 and Later

Creating an instance

Yes

Yes

Restarting a DB instance

Yes

Yes

Modifying parameters

Yes

Yes

Applying parameters

Yes

Yes

Resetting a password

Yes

Yes

Creating a full backup

No

Yes

Creating a differential backup

No

Yes

Deleting a backup

No

Yes

Modifying the backup policy

No

Yes

Restoring data to the original instance

No

Yes

Restoring data to a new instance

No

Yes

Restoring data to an existing instance

No

Yes

Scaling up storage

Yes

Yes

Changing CPU and memory specifications of an instance

Yes

Yes

Hot patch upgrade

No

Yes

In-place upgrade

Yes (The version can be upgraded only to 3.0 or later.)

Yes

Gray upgrade

No

Yes (only supported in version 3.207 or later)

Viewing monitoring metrics

Yes

Yes

Deleting an instance

Yes

Yes

Rebuilding a deleted instance

No

Yes

Querying the disk usage

Yes

Yes

Creating a database

Yes

Yes

Querying a database

Yes

Yes

Creating a schema and user

Yes

Yes

Deleting a schema and user

Yes

Yes

Performing database operations

Yes

Yes