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Database Transmission Service

Pre-check items

Pre-check items (MySQL)

Database Transmission Service (DTS) performs various checks on databases before creating or configuring migration or synchronization tasks for RDS for MySQL. This topic introduces the details of check items.

tip

The pre-check result levels include Error and Warning, as detailed below:

Error: indicates an error-level check result. When this type of error occurs during task creation pre-check, it can not be ignored. Relevant information must be modified according to the prompts before re-running the pre-check.

Warning: indicates a prompt-level pre-check result. When this type of error occurs during task creation pre-check, it can be ignored.

Item	Database type	Check scope	Level	Check content	Remarks
Target database ReadOnly configuration check	Target database	All migrations All synchronization	Error	Check if the target database's ReadyOnly configuration meets migration or synchronization requirements.	Pre-check fails when any of the following ReadOnly parameter values are met: super_read_only: value is ON. innodb_read_only: value is ON. transaction_read_only: value is ON. read_only: value is ON and the migration account lacks SUPER and CONNECTION_ADMIN privileges
Target database trigger check	Target database	All migrations All synchronization	Warning	Check if the target database has triggers.	None
Target table/database existence check	Target database	Full migration Full initialization	Warning	Check if the existence of the target instance database meets expectations.	If full migration is selected without schema migration, or full initialization without schema initialization, migration or initialization might fail if the corresponding structure does not exist in the target databases and tables.
Target table/database existence check	Target database			Incremental migration Incremental synchronization	Warning	Check whether the table existence in the target instance meets expectations.	If incremental migration or synchronization is selected without schema migration or initialization, migration or synchronization may fail if the target database tables lack the corresponding structure. tip You can perform schema migration or initialization using incremental DDL.
Source table/database existence check	Source database	Full migration Full initialization	Warning	Check whether the existence of the database in the source instance meets expectations.	If full migration is selected without schema migration, or full initialization without schema initialization, migration or initialization might fail if the corresponding structure does not exist in the source database tables.
Source table/database existence check	Source database			Incremental migration Incremental synchronization	Warning	Check whether the existence of tables in the source instance meets expectations.	If incremental migration or synchronization is selected without schema migration or initialization, migration or synchronization may fail if the target database tables lack the corresponding structure. tip You can perform schema migration or initialization using incremental DDL.
Target database permission check	Target database	All migrations All synchronization	Warning	Check whether the account privileges of the target instance meet the requirements for migration or synchronization.	The required permissions vary depending on the migration or synchronization type, as follows: Incremental migration or incremental synchronization requires the target database account to have SELECT, INSERT, UPDATE, DELETE, CREATE, INDEX, ALTER, and DROP permissions. Full migration or full initialization requires the target database account to have SELECT, INSERT, and UPDATE permissions. Schema migration or schema initialization requires the target database account to have SELECT, CREATE, INDEX, and ALTER permissions. User migration requires the target database account to have CREATE USER and GRANT OPTION permissions.
Check if the innodb_strict_mode setting is consistent.	Source database Target database	All migrations All synchronization	Warning	Check whether InnoDB strict mode settings are consistent	None
Check innodb_large_prefix compatibility	Source database Target database	All migrations All synchronization	Error	Check the compatibility of innodb_large_prefix between the source database and the target database.	None
Check whether SQL_MODE is consistent.	Source database Target database	All migrations All synchronization	Warning	Check if the SQL_MODE of the source database and target database are consistent.	None
Account existence check	Source database Target database	User migration	Warning	Check whether the accounts to be migrated in the source database already exist in the target database.	None
Source and target database table name case sensitivity check	Source database Target database	All migrations All synchronization	Warning	Check whether the lower_case_table_names of the source database and target database are consistent.	None
Check whether the transaction isolation level (tx_isolation) is consistent	Source database Target database	All migrations All synchronization	Warning	Check whether the transaction isolation level is consistent.	None
Check whether the Definer of the metadata exists.	Source database Target database	Schema migration Schema initialization	Warning	Check whether the Definer of views, stored procedures, functions, and triggers exists in the target database.	The structure definer not existing may cause the structure to be unusable after migration
Database version check	Source database Target database	All migrations All synchronization Data subscription	Warning	Check whether the versions of the source and target databases are supported.	Both source and target database versions must be above MySQL 5.5.
Database connectivity check	Source database Target database	All migrations All synchronization Data subscription	Error	Check whether the data transmission server can connect to the source database and the target database.	None
Check foreign key dependencies of tables to be migrated	Source database Target database	All migrations All synchronization	Warning	Check whether tables referenced by foreign keys in the source database for migration or synchronization exist or are within the migration or synchronization scope.	None
Account migration dependency check	Source database Target database	User migration	Warning	Check whether all schema migrations authorized to the source database account have been migrated to the target database.	None
Major database version detection	Source database Target database	All migrations All synchronization	Warning	Check whether the major versions of the source database and target database are consistent.	None
Source database ServerID check	Source database	Incremental migration Incremental synchronization Data subscription	Warning	Check whether the ServerID of the source database is 1.	If the ServerID of the source database is 1, the system can not confirm whether ServerID is configured. You need to confirm it by yourself.
Source database gtid mode enablement check	Source database	All migrations	Warning	Check if the source database instance parameter gtid mode is set to ON.	When the MySQL version is earlier than 8.0 and the parameter gtid_mode is disabled, foreign key cascading deletion may fail during data migration, resulting in data differences. When gtid mode is disabled, the source database instance does not support switching to the primary.
Source database gtid mode enablement check	Source database				All synchronization	Warning		When the source database version is MySQL 5.6 or later, both gtid_mode and enforce_gtid_consistency must be set to ON. When the MySQL version is earlier than 8.0 and the parameter gtid_mode is disabled, foreign key cascading deletion may fail during data synchronization, resulting in data differences.
Source database GIPK check	Source database	All migrations All synchronization Data subscription	Warning	Check whether GIPK is enabled in the source database.	If the source database instance does not support the parameter sql_generate_invisible_primary_key, meaning the version of the source database instance is less than 8.0.29, then this pre-check will pass by default.
Check if the source database and tables contain primary keys	Source database	Full migration Incremental migration Full initialization Incremental synchronization	Warning	Check whether the source database tables contain a primary key. Absence of a primary key may cause inconsistent data behavior and requires adding a primary key. Migrating large tables without primary keys (larger than 100M) puts significant pressure on both the source and target databases. It is recommended to fully assess database performance and migrate large tables without primary keys during off-peak business hours.	None
Source table storage engine check	Source database	Incremental migration Incremental synchronization Data subscription	Warning	Check whether the tables to be migrated or synchronized in the source database use the InnoDB engine.	Data migration supports storage engines including InnoDB, MyISAM, and RocksDB. During data migration, if the source database is not using the InnoDB storage engine, the system automatically converts it to InnoDB. Data synchronization and data subscription support the InnoDB storage engine.
Source table storage engine check	Source database			Schema migration		Warning	Check whether tables using engines other than InnoDB automatically convert to the InnoDB engine during schema migration or initialization.
Source end Binlog enablement check	Source database	Incremental migration Incremental synchronization Data subscription	Error	Check whether Binlog is enabled in the source database.	Binlog parameters must meet the following requirements simultaneously: log_bin value is ON. binlog_format value is ROW. For MySQL 5.6.2 and later, binlog_row_image value is FULL.
Check source database log_slave_updates	Source database	Incremental migration Incremental synchronization Data subscription	Warning	Check whether the source database log_slave_updates is ON.	None
Source database permission check	Source database	All migrations All synchronization Data subscription	Warning	Verify whether the source database's account privileges meet the requirements for migration, synchronization, or subscription.	Check if the source database has REPLICATION SLAVE and REPLICATION CLIENT permissions. The password for the source database account can not exceed 32 characters.
Check if the source end has SHOW CREATE ROUTINE permission.	Source database	Schema migration Schema initialization	Error	Check whether the source database has the SHOW CREATE ROUTINE permission.	The source database must have SHOW CREATE ROUTINE permission to obtain the creation statements of Routine objects to be migrated or initialized.
Check whether the source end has SHOW CREATE VIEW permission.	Source database	Schema migration Schema initialization	Warning	Check whether the source database has SHOW CREATE VIEW permission	The source database requires SHOW CREATE VIEW permission to retrieve the creation statement of View objects to be migrated or synchronized.
Target database EventScheduler configuration check	Target database	Schema migration	Warning	Check whether the EventScheduler configuration of the target database meets expectations. When event_scheduler is set to ON, events will not be executed after migration.	This check item is required when the migration type is schema migration, and event migration is needed.
Target database timezone check	Source database Target database	Schema migration	Warning	Check if the target database's time zone is consistent.	This check item is required when the migration type is schema migration, and event migration is needed.
Database connection and architecture wildcard rule check	Source database	All migrations All synchronization Data subscription	Warning	Connect or expand the source wildcard.	None
Existence check of the source table or database	Source database	All migrations All synchronization Data subscription	Error	Check whether the specified table/database exists in the source database.	None
Source database incremental position check	Source database	Incremental migration Incremental synchronization Data subscription	Warning	Check if the incremental position exists in the source database.	None
Check tables without primary keys in the source database	Source database	All migrations All synchronization	Error	Check the rows and capacity of tables without primary keys in the source database (tables larger than 100,000 rows or 100MB).	None
Target database SET_USER_ID permission check	Target database	All migrations All synchronization	Warning	Check whether the account SET_USER_ID privilege of the target database meets the migration requirements.	None
Target database max_allowed_packet configuration check	Target database	All migrations All synchronization	Warning	Check if the target database's max_allowed_packet is less than 16MB.	None
Target database innodb_rollback_on_timeout close check	Target database	All migrations All synchronization	Warning	Check whether innodb_rollback_on_timeout is also disabled when innodb_deadlock_detect is disabled in the target database.	None
Migration permission check	Source database	User migration	Warning	Check whether the account migration includes All permissions?	None
Target database partial_revokes configuration check	Target database	User migration	Warning	Whether partial_revokes of the database is enabled.	This check applies only when both source and target MySQL versions are above 8.0 and the source migration account has Partial REVOKE permissions.
Target database log_bin_trust_function_creators enablement check	Target database	All migrations All synchronization Schema migration	Warning	Check whether log_bin_trust_function_creators is enabled in the target database.	None
Bidirectional synchronization table auto-increment column check	Source database Target database	Bidirectional synchronization	Warning	Check whether the source and target databases contain tables with auto-increment columns during bidirectional synchronization.	None
Bidirectional synchronization source and target databases synchronization condition check	Source database Target database	Bidirectional synchronization	Warning	Check whether the source database and the target database in bidirectional synchronization meet the synchronization conditions.	Check whether the migration account has read and write permissions to mark the databases and tables.
Source and target same-name table existence check	Source database Target database	All migrations All synchronization	Warning	Check whether there are tables with the same name on the source and target ends.	If the destination contains tables of the same name, the migration or synchronization task may encounter errors or risk data overwriting.
Environment detection.	Source database Target database	All migrations All synchronization Data subscription	Warning	Environment detection.	None
Data synchronization version check	Source database Target database	All synchronization	Error	Data synchronization version check.	The pre-check fails when the source database version is lower than MySQL 5.6.
Check tables in the same instance and database on the source and target ends	Source database Target database	All migrations Unidirectional synchronization	Warning	Check whether the source and target ends are the same instance and database & table.	None
Destination account number migration permission check	Target database	All migrations All synchronization	Warning	Check whether the migrating account has permission to create users.	The destination account must have GRANT OPTION privileges, or user migration may fail.
Millisecond-level latency monitoring availability check	Source database	MySQL to MySQL data synchronization task	Error	Check the availability of millisecond-level latency monitoring for the source database.	You may encounter the following error messages when the pre-check fails: No permission to create heartbeat table and the heartbeat table does not exist. No permission to write to the heartbeat table. Detected that the source database or target database system variable read_only = ON, and the account lacks SUPER and CONNECTION_ADMIN permissions, preventing update operations. detected the system variable value in the source database or target database is ON, update operations cannot be performed; the system variables are as follows: super_read_only innodb_read_only transaction_read_only tx_read_only If you encounter the above error messages, modify the corresponding issues based on the prompts. For detailed operations, refer to what to do if enabling millisecond-level latency monitoring pre-check fails?.
Source end proxy check	Source database	Incremental migration Incremental synchronization Incremental subscription	Error	Check whether the source end is a proxy.	When a non-Volcano Engine instance serves as the source end for data transmission, the source database does not support configuring multi-node proxy addresses. During incremental data synchronization, incremental migration, and incremental subscription, DTS requires establishing a stable long connection with specific database instances. The load balancing or routing mechanism of multi-node proxy may cause connection drift or log parsing failure. It is recommended to configure a single node connection address directly or use a database gateway (DG) for access.

Last updated: 2026.07.31 11:38:45