Changing Task Parameters

DRS allows you to change task parameters based on service requirements.

Constraints

You can change parameters of a synchronization task in the Configuration, Full, Full synchronization failed, Incremental, Incremental synchronization failed, or Paused state.
After some parameters of a task are changed, the changes take effect only after you restart the task by referring to Restarting a Synchronization Task. In addition, operations for resetting a task, resuming a task, rebuilding a task, performing primary/standby switchover, or changing the flow control in the full synchronization phase will restart task processes for the parameter changes to take effect.
You can change parameters only for the synchronization tasks of the following engines: For details about common task parameters, see Task Parameter Description.
- MySQL->MySQL
- MySQL->PostgreSQL
- MySQL -> GaussDB Distributed
- MySQL -> GaussDB Primary/Standby
- MySQL->GaussDB(DWS)
- MySQL->GaussDB(for MySQL)
- MySQL->Kafka
- MySQL->CSS/ES
- MySQL->Oracle

Procedure

On the Data Synchronization Management page, locate the target synchronization task.
Click the task name. The Basic Information page is displayed.
Choose Parameters on the left pane. On the Parameters tab page, change the parameters of the current synchronization task.

Figure 1 Parameters
Click Save or Cancel.
- To save your changes, click Save. In the displayed dialog box, click Yes.
- To cancel your changes, click Cancel. In the displayed dialog box, click Yes.
Restart the task for the changes to take effect. You can click Restart in the upper right corner or restart the task by referring to Restarting a Synchronization Task.

In addition, operations for resetting a task, resuming a task, rebuilding a task, performing primary/standby switchover, or changing the flow control in the full synchronization phase will restart task processes for the parameter changes to take effect.

Task Parameter Description

**Table 1** Task parameters
Parameter	Description	Value Range	Default Value	Type	Restart Required
applier_thread_num	Number of threads for writing data to the destination database during the full synchronization phase.	The value range depends on the task specifications. Micro: 1-4 Small: 1-4 Medium: 1-8 Large: 1-18 Ultra-large: 1-24	The default value depends on the task specifications. Micro: 2 Small: 2 Medium: 4 Large: 6 Ultra-large: 12	int	Yes
read_task_num	Number of threads for reading data from the source database during the full synchronization phase.	The value range depends on the task specifications. Micro: 1-2 Small: 1-2 Medium: 1-4 Large: 1-8 Ultra-large: 1-12	The default value depends on the task specifications. Micro: 1 Small: 1 Medium: 2 Large: 4 Ultra-large: 6	int	Yes
shard_task_num	Number of sharding threads in the source database during the full synchronization phase.	The value range depends on the task specifications. Micro: 1-2 Small: 1-2 Medium: 1-4 Large: 1-8 Ultra-large: 1-8	The default value depends on the task specifications. Micro: 1 Small: 1 Medium: 2 Large: 4 Ultra-large: 4	int	Yes
increment_writer_num	Number of threads for writing data to the destination database during the incremental synchronization phase.	The value range depends on the task specifications. Micro: 1-8 Small: 1-16 Medium: 1-32 Large: 1-128 Ultra-large: 1-128	The default value depends on the task specifications. Micro: 4 Small: 8 Medium: 16 Large: 64 Ultra-large: 64	int	Yes
relay_socket_timeout	Timeout interval for obtaining logs from the source database during the incremental synchronization phase.	30000-2147483647 ms	30000 ms	int	Yes
datamove_source_socket_timeout	Timeout interval for obtaining data from the source database during the full synchronization phase.	120000-2147483647 ms	120000 ms	int	Yes