Primary Server¶
vacuum_defer_cleanup_age¶
Parameter description: Specifies the number of transactions by which VACUUM will defer the cleanup of invalid row-store table records, so that VACUUM and VACUUM FULL do not clean up deleted tuples immediately.
Type: SIGHUP
Value range: an integer ranging from 0 to 1000000. 0 means no delay.
Default value: 0
data_replicate_buffer_size¶
Parameter description: Specifies the size of memory used by queues when the sender sends data pages to the receiver. The value of this parameter affects the buffer size copied for the replication between the primary and standby servers.
Type: POSTMASTER
Value range: an integer ranging from 4 to 1023. The unit is MB.
Default value: 16MB for CNs and 128MB for DNs
enable_data_replicate¶
Parameter description: Specifies the data synchronization mode between the primary and standby servers when data is imported to row-store tables in a database.
Type: USERSET
Value range: Boolean
on indicates that data pages are used for the data synchronization between the primary and standby servers when data is imported to row-store tables in a database. This parameter cannot be set to on if replication_type is set to 1.
off indicates that the primary and standby servers synchronize data using Xlogs while the data is imported to a row-store table.
Default value: on
enable_incremental_catchup¶
Parameter description: Specifies the data catchup mode between the primary and standby nodes.
Type: SIGHUP
Value range: Boolean
on indicates that the standby node uses the incremental catchup mode. That is, the standby server scans local data files on the standby server to obtain the list of differential data files between the primary and standby nodes and then performs catchup between the primary and standby nodes.
off indicates that the standby node uses the full catchup mode. That is, the standby node scans all local data files on the primary node to obtain the list of differential data files between the primary and standby nodes and performs catchup between the primary and standby nodes.
Default value: on
wait_dummy_time¶
Parameter description: Specifies the maximum duration for the primary, standby, and secondary clusters to wait for the secondary cluster to start in sequence and the maximum duration for the secondary cluster to send the scanning list when incremental data catchup is enabled.
Type: SIGHUP
Value range: Integer, from 1 to INT_MAX, in seconds.
Default value: 300s
Caution
The unit can only be second.