Replication Parameters of Two Database Instances

RepOriginId

Parameter description: This parameter is a session-level GUC parameter. In bidirectional logical replication, set it to a non-zero value to avoid infinite data replication.

This is a USERSET parameter. Set it based on method 3 in Table 1.

Value range: an integer ranging from 0 to 2147483647

Default value: 0

stream_cluster_run_mode

Parameter description: Specifies whether a DN is in the primary or standby instance in dual-instance streaming DR scenarios. For single-instance scenarios, the DN is in the primary instance by default.

This is a POSTMASTER parameter. Set it based on instructions in Table 1.

Value range: enumerated values

• cluster_primary indicates that the node is in the primary instance.
• cluster_standby indicates that the node is in the standby instance.

Default value: cluster_primary

enable_roach_standby_cluster

Parameter description: Sets the standby database instances to read-only in dual-database instance mode. Only users with the sysadmin permission can access this parameter.

This is a POSTMASTER parameter. Set it based on instructions in Table 1.

Value range: Boolean

• on indicates that the read-only mode is enabled for the standby database instances.
• off indicates that the read-only mode is disabled for the standby database instances. In this case, the standby database instances can be read and written.

Default value: off

hadr_process_type

Parameter description: Specifies the process type in dual-instance streaming DR scenarios.

This is a SIGHUP parameter. Set it based on instructions in Table 2.

Value range: enumerated values

• none indicates that there is no process.
• failover indicates that the DR database instance is being upgraded.
• switchover_promote indicates the process of upgrading the DR database instance to the primary database instance during the primary/standby database instance switchover.
• switchover_demote indicates the process of demoting the primary database instance to the DR database instance during the primary/standby database instance switchover.

Default value: none