Troubleshoot DTS data synchronization precheck failures-Data Transmission Service(DTS)-阿里云帮助中心

DTS prechecks the source and destination databases before running a data synchronization task. Use this reference to identify and fix precheck failures.

Precheck item	Possible cause	Solution
Source database connectivity Destination database connectivity	Invalid database account or password.	Obtain the correct password and update it in the DTS console. For more information, see Change a database password.
	The IP address used to connect to the source or destination database is blocked.	For MySQL, re-authorize the database account and add DTS server CIDR blocks to the database whitelist. For more information about the CIDR blocks of DTS servers, see Whitelist DTS server IP addresses. For SQL Server, disable the firewall or trigger settings. For Oracle, set the `TCP.VALIDNODE_CHECKING` parameter to `no` and restart the process.
	A firewall is enabled on the database server.	Disable the firewall.
Source database version	The database version is not supported. For more information, see Data synchronization scenarios.	Upgrade or downgrade the database version.
Database existence	If the destination database does not exist, DTS may fail to create it due to: The database name contains characters other than letters, digits, underscores (_), and hyphens (-). The database character set is not UTF8, GBK, Latin1, or UTF8MB4. The destination database account lacks the required permissions.	Create the database in the destination instance, or grant the required permissions to the database account.
Source database permissions	The database account lacks the required permissions. For example, the dts.precheck.Unexpected error check item fails. Note Required permissions vary by database type. For more information, see Overview of data synchronization scenarios.	Grant the required permissions to the database account, or use an account that already has the permissions. Note Verify the account permissions with other tools before proceeding.
Destination database permissions
Object name conflicts	The source and destination databases or tables share the same name.	Rename the conflicting database or tables in the destination. Use object name mapping to rename conflicting objects in the destination. For more information, see Set object names in the destination instance. Remove the conflicting objects. For more information, see Remove an object from a data synchronization task.
Source database server_id	The `server-id` parameter is not set to an integer greater than or equal to 2.	Update the `server-id` parameter in the source database. For more information, see Resolve the server_id precheck failure.
Source database binary logging	Binary logging is disabled for the source database.	Enable binary logging in the source database. For more information, see Binary log enablement.
Source database binary log format	The binary log format of the source database is set to ROW.	Run `set global binlog_format='ROW';` on the source database and restart MySQL.
FOREIGN KEY constraint integrity	A parent table that a child table depends on is not included in the required objects.	Remove the foreign key dependency from the child table. Add the parent table to the required objects. For more information, see Add a synchronization object. Remove the child table from the required objects. For more information, see Remove an object from a data synchronization task.
Storage engine	The source table uses the FEDERATED, MRG_MyISAM, or TokuDB storage engine.	Change the source table storage engine to InnoDB.
Character set	The required objects use an unsupported character set, such as UCS2.	Change the source table character set to UTF8, GBK, Latin1, or UTF-8MB4.
Topology conflicts	The synchronization topology is not supported. For more information, see Synchronization topologies.	Stop the conflicting task or wait for it to complete, then retry.
MySQL password format	The source database password uses a deprecated format.	Update the password format. See the MySQL old_passwords variable.