Updated on 2025-06-30 GMT+08:00

FlexusRDS for PostgreSQL Constraints

The following tables list the constraints designed to ensure the stability and security of FlexusRDS for PostgreSQL instances.

Specifications and Performance

Table 1 Specifications

Item

Constraints

Description

Storage space

The purchased storage space depends on the selected instance class.

You can enable storage autoscaling for your instance after the instance is created. Storage can autoscale to no more than 4 TB.

Quotas

Table 2 Quotas

Item

Constraints

Description

Tags

A maximum of 20 tags can be added for a DB instance.

For more information, see Managing Tags.

Free backup space

FlexusRDS provides free backup space of the same size as your purchased storage space.

After you pay for the storage space of your instance, you will get a backup space of the same size for free. For more information, see How Is FlexusRDS Backup Data Billed?

Retention period of automated backups

The default value is seven days and cannot be changed.

-

Log query

  • Error log records: 2,000
  • Slow query log records: 2,000

For more information, see Logs.

Naming

Table 3 Naming

Item

Constraints

Instance name

  • 4 to 64 characters long
  • Must start with a letter. Only letters (case sensitive), digits, hyphens (-), underscores (_), and periods (.) are allowed.

Backup name

  • Must be 4 to 64 characters long.
  • Must start with a letter. Only letters (case sensitive), digits, hyphens (-), and underscores (_) are allowed.

Security

Table 4 Security

Item

Constraints

root password

  • 8 to 32 characters long
  • Must contain at least three types of the following characters: uppercase letters, lowercase letters, digits, and special characters (~!@#%^*-_=+?,).

For more information, see Resetting the Administrator Password to Restore root Access.

Database port

5432

System account

To provide O&M services, the system automatically creates system accounts when you create PostgreSQL instances. These system accounts are unavailable to you.

  • rdsAdmin: a management account with the highest permission. It is used to query and modify instance information, rectify faults, migrate data, and restore data.
  • pg_execute_server_program: an account that allows executing programs on the database server as the user the database runs as with COPY and other functions which allow executing a server-side program.
  • pg_read_all_settings: an account that reads all configuration variables.
  • pg_read_all_stats: an account that reads all pg_stat_* views and uses various extension-related statistics.
  • pg_stat_scan_tables: an account that executes monitoring functions that may take ACCESS SHARE locks on tables, potentially for a long time.
  • pg_signal_backend: an account that signals another backend to cancel a query or terminate its session.
  • pg_read_server_files: an account that allows reading files from any location the database can access on the server with COPY and other file-access functions.
  • pg_write_server_files: an account that allows writing to files in any location the database can access on the server with COPY and other file-access functions.
  • pg_monitor: an account that reads and executes various monitoring views and functions. This role is a member of pg_read_all_settings, pg_read_all_stats, and pg_stat_scan_tables.
  • rdsRepl: a replication account, used to synchronize data from the primary instance to the standby instance or read replicas.
  • rdsBackup: a backup account, used for backend backup.
  • rdsMetric: a metric monitoring account used by watchdog to collect database status data.

Instance Operations

Table 5 Instance operations

Item

Constraints

Instance deployment

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

Data migration

Data Replication Service (DRS) can be used to migrate data. It is easy to use and can complete a migration task in minutes. It facilitates data transfer between databases, helping you reduce DBA labor costs and hardware costs.

Primary/Standby replication

FlexusRDS for PostgreSQL uses a primary/standby dual-node replication cluster. You do not need to set up replication additionally. The standby DB instance is not visible to you and therefore you cannot access it directly.

Rebooting a DB instance

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

Viewing backups

You can download automated and manual backups for local storage. To download a backup, you can use OBS Browser+, the current browser, or the download URL.

For more information, see Downloading a Full Backup File.

Log management

Logging is enabled by default and cannot be disabled.