This topic describes the permissions of privileged accounts and standard accounts in PolarDB.
Background information
For the sake of security, you must manage and control account permissions in PolarDB. An account can only perform operations on which it is granted permissions. PolarDB adopted a role-based RAM model to manage account permissions. In this model, accounts are assigned different roles, each of which has specified permissions. Each account can perform operations on which it is granted permissions. This method can control account permissions and protect database security.
PolarDB provides two roles: privileged accounts and standard accounts.
Privileged accounts are used for management tasks, such as creating databases, granting basic permissions, and creating publications and subscriptions.
Standard accounts perform business logic operations.
PolarDB uses this permission system to build database operation types, implement the RAM model, and ensure permission security.
Permissions granted to a privileged account
Account | Permission |
Privileged account | Create a database. For more information, see Create a database. |
Create an extension. For more information, see Plug-ins. | |
Create an account which has lower or equal permissions. For more information, see Create a user. | |
Create and use an event trigger. For more information, see Create a trigger. | |
Create and modify a type. For more information, see Create an object type. | |
Invoke a garbage collection instruction. For more information, see Garbage collection mechanism. | |
Create and modify an external FDW. For more information, see Read and write external data files by using oss_fdw. | |
Modify the sequence used by ROWID. For more information, see ALTER SEQUENCE. | |
Create publications and subscriptions. Example:
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Create a system context. Example:
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Use two-phase transactions. Example:
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Send signals. Example:
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View the status of background processes. Example:
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Modify an object name. Example:
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Permissions not granted to privileged accounts or standard accounts
The following permissions are prohibited for the sake of database security.
Account | Permission |
Privileged account and standard account | Create a folder. |
Modify system parameters. | |
Create a tablespace. | |
Kill a superuser process. | |
Execute an untrusted language. Note Only PL/SQL is a trusted language. Other languages are untrusted and cannot be executed. |
User group permissions
PolarDB for PostgreSQL (Compatible with Oracle) is built on the PostgreSQL protocol and uses certain group permissions from PostgreSQL. The inheritance mechanism of these group permissions is detailed in the following table. These permissions have a union relationship with the permissions owned by privileged users. Specifically, the set of permissions is the sum of these two types of permissions.
Permission | Ownership | Description |
pg_read_all_stats & pg_stat_scan_tables | Full | Reads related statistics. |
pg_signal_backend | Full | Signals another backend to cancel a query or terminate its session. |
pg_polar_superuser | Full | Contains a series of permissions of privileged users. |
pg_polar_replication | Full | Provides the streaming replication permission. |
pg_monitor | Full | Reads/executes various monitoring views and functions. The read and write permissions on local files are denied. |
pg_read_all_data & pg_write_all_data | Limited | Reads all user tables and most system tables and writes data to all user tables. Some system tables are set invisible for security reasons. |
pg_read_all_settings | Limited | Reads all configuration variables within granted permissions. Some variables are set invisible for security reasons. |
pg_read_server_files & pg_write_server_files | Prohibited | Not allowed to read or write local files. |
pg_execute_server_program | Prohibited | Not allowed to execute binary commands. |