__tencentdb__
in the source database to record the data comparison information during the sync task.__tencentdb__
system database in the source database will not be deleted after the sync task ends.__tencentdb__
system database uses a single-threaded connection wait mechanism and occupies a very small space, about 0.01%–0.1% of the storage space of the source database; for example, if the source database is 50 GB, __tencentdb__
will be about 5–50 MB. Therefore, it has almost no impact on the performance of the source database and will not preempt resources.GRANT RELOAD,LOCK TABLES,REPLICATION CLIENT,REPLICATION SLAVE,SHOW VIEW,PROCESS,SELECT ON *.* TO 'account'@'%' IDENTIFIED BY 'password';GRANT ALL PRIVILEGES ON `__tencentdb__`.* TO 'account'@'%';FLUSH PRIVILEGES;
user1
corresponding to DEFINER
([DEFINER = user1]
) in the source database is the same as the sync account user2
, and if not, DTS will change the SQL SECURITY
attribute of user1
in the target database from DEFINER
to INVOKER
([INVOKER = user1]
) after the sync, and set the DEFINER
in the target database to the sync account user2
([DEFINER = sync account user2]
). If the view definition in the source database is too complex, the task may fail.STATEMENT
format, sync will fail.ALTER VIEW
statement is not supported and will be skipped during sync.STATEMENT
format into the source database.__tencentdb__
during incremental sync.Operation Type | SQL Statements |
DML | INSERT, UPDATE, and DELETE |
DDL | CREATE DATABASE, DROP DATABASE, ALTER DATABASE, CREATE TABLE, ALTER TABLE, DROP TABLE, TRUNCATE TABLE, RENAME TABLE, CREATE VIEW, DROP VIEW, CREATE INDEX, and DROP INDEX Note: DDL statements involving partitions cannot be synced. |
Type | Environment Requirement |
Requirements for source database | The source and target databases can be connected. Requirements for the instance parameters: The `server_id` parameter in the source database must be set manually and cannot be 0. `row_format` for the source databases/tables cannot be set to `FIXED`. The values of the `lower_case_table_names` variable in both the source and target databases must be the same. The `connect_timeout` variable in the source database must be greater than or equal to 10. Requirements for binlog parameters: The `log_bin` variable in the source database must be set to `ON`. The `binlog_format` variable in the source database must be set to `ROW`. The `binlog_row_image` variable in the source database must be set to `FULL`. On MySQL 5.6 or later, if the `gtid_mode` variable is not `ON`, an alarm will be triggered. We recommend you enable `gtid_mode`. It is not allowed to set `do_db` and `ignore_db`. If the source instance is a replica database, the `log_slave_updates` variable must be set to `ON`. We recommend you retain the binlog of the source database for at least three days; otherwise, the task cannot be resumed from the checkpoint and will fail. Foreign key dependency: Foreign key dependency can be set to only one of the following two types: `NO ACTION` and `RESTRICT`. During partial table sync, tables with foreign key dependency must be migrated. |
Requirements for the target database | The target database version must be later than or equal to the source database version. The target database must have sufficient storage space. If you select Full data initialization as the initialization type, the target database space must be at least 1.2 times the space of databases/tables to be synced in the source database. The target database cannot have sync objects such as tables and views with the same name as those in the source database. The `max_allowed_packet` parameter of the target database must be set to 4 MB or above. |
Other requirements | The environment variable `innodb_stats_on_metadata` must be set to `OFF`. |
Parameter | Description |
Billing Mode | Monthly subscription and pay-as-you-go billing are supported. |
Source Instance Type | Select MySQL, which cannot be changed once configured. |
Source Instance Region | Select the source instance region, which cannot be changed once configured. |
Target Instance Type | Select MySQL, which cannot be changed once configured. |
Target Instance Region | Select the target instance region, which cannot be changed once configured. |
Specification | Select a specification based on your business needs. The higher the specification, the higher the performance. |
Category | Parameter | Description |
Task Configuration | Task Name | DTS will automatically generate a task name, which is customizable. |
| Running Mode | Immediate execution and scheduled execution are supported. |
Source Instance Settings | Source Instance Type | Select the source instance type selected during purchase, which cannot be changed once configured. |
| Source Instance Region | Select the source instance region selected during purchase, which cannot be changed once configured. |
| Service Provider | For a self-built database (such as a CVM-based one) or TencentDB database, select Others. For a third-party cloud database, select the corresponding service provider.
In this scenario, select Others. |
| Access Type | Select a type based on your scenario. In this scenario, select Direct Connect or VPN Access , and you need to configure VPN-IDC interconnection as instructed in Direct Connect or VPN Access: Configuring VPN-IDC Interconnection. For the preparations for different access types, see Overview. Public Network: The source database can be accessed through a public IP. Self-Build on CVM: The source database is deployed in a CVM instance. Direct Connect: The source database can be interconnected with VPCs through Direct Connect. VPN Access: The source database can be interconnected with VPCs through VPN Connections. Database: The source database is a TencentDB instance. CCN: The source database can be interconnected with VPCs through CCN. VPC: The source and target databases are both deployed in Tencent Cloud VPCs. To use the VPC access type, submit a ticket for application. |
| VPC-based Direct Connect Gateway/VPN Gateway | Only VPC-based Direct Connect gateway is supported. You need to confirm the network type associated with the gateway.
VPN Gateway: Select a VPN Gateway instance. |
| VPC | Select a VPC and subnet associated with the VPC-based Direct Connect Gateway or VPN Gateway. |
| Host Address | IP address or domain name for accessing the source MySQL instance. |
| Port | Port for accessing the source MySQL instance. |
| Account | Account of the source instance, which must have the required permissions. |
| Password | Password of the source instance account. |
Target Instance Settings | Target Instance Type | The target instance type selected during purchase, which cannot be changed. |
| Target Instance Region | The target instance region selected during purchase, which cannot be changed. |
| Access Type | Select a type based on your scenario. In this scenario, select Database. |
| Instance ID | Target instance ID. |
| Account | Account of the target instance, which must have the required permissions. |
| Password | Password of the target instance account. |
Category | Parameter | Description |
Task Configuration | Task Name | DTS will automatically generate a task name, which is customizable. |
| Running Mode | Immediate execution and scheduled execution are supported. |
Source Instance Settings | Source Instance Type | Select the source instance type selected during purchase, which cannot be changed once configured. |
| Source Instance Region | Select the source instance region selected during purchase, which cannot be changed once configured. |
| Service Provider | For a self-built database (such as a CVM-based one) or TencentDB database, select Others. For a third-party cloud database, select the corresponding service provider.
In this scenario, select Others. |
| Access Type | Select a type based on your scenario. In this scenario, select Database. For the preparations for different access types, see Overview. Public Network: The source database can be accessed through a public IP. Self-Build on CVM: The source database is deployed in a CVM instance. Direct Connect: The source database can be interconnected with VPCs through Direct Connect. VPN Access: The source database can be interconnected with VPCs through VPN Connections. Database: The source database is a TencentDB instance. CCN: The source database can be interconnected with VPCs through CCN. VPC: The source and target databases are both deployed in Tencent Cloud VPCs. To use the VPC access type, submit a ticket for application. |
| Instance ID | |
| Account | Account of the source instance, which must have the required permissions. |
| Password | Password of the source instance account. |
Target Instance Settings | Target Instance Type | The target instance type selected during purchase, which cannot be changed. |
| Target Instance Region | The target instance region selected during purchase, which cannot be changed. |
| Access Type | Select a type based on your scenario. In this scenario, select Database. |
| Instance ID | Target instance ID. |
| Account | Account of the target instance, which must have the required permissions. |
| Password | Password of the target instance account. |
Category | Parameter | Description |
Task Configuration | Task Name | DTS will automatically generate a task name, which is customizable. |
| Running Mode | Immediate execution and scheduled execution are supported. |
Source Instance Settings | Source Instance Type | Select the source instance type selected during purchase, which cannot be changed once configured. |
| Source Instance Region | Select the source instance region selected during purchase, which cannot be changed once configured. |
| Service Provider | For a self-built database (such as a CVM-based one) or TencentDB database, select Others. For a third-party cloud database, select the corresponding service provider.
In this scenario, select Alibaba Cloud. |
| Access Type | For a third-party cloud database, you can select ublic Network generally or select VPN Access, Direct Connect, or CCN based on your actual network conditions.In this scenario, select Public Network. For the preparations for different access types, see Overview. Public Network: The source database can be accessed through a public IP. Self-Build on CVM: The source database is deployed in a CVM instance. Direct Connect: The source database can be interconnected with VPCs through Direct Connect. VPN Access: The source database can be interconnected with VPCs through VPN Connections. Database: The source database is a TencentDB instance. CCN: The source database can be interconnected with VPCs through CCN. VPC: The source and target databases are both deployed in Tencent Cloud VPCs. To use the VPC access type, submit a ticket for application. |
| Host Address | IP address or domain name for accessing the source instance. |
| Port | Source instance port. |
| Account | Account of the source instance, which must have the required permissions. |
| Password | Password of the source instance account. |
Target Instance Settings | Target Instance Type | The target instance type selected during purchase, which cannot be changed. |
| Target Instance Region | The target instance region selected during purchase, which cannot be changed. |
| Access Type | Select a type based on your scenario. In this scenario, select Database. |
| Instance ID | Target instance ID. |
| Account | Account of the target instance, which must have the required permissions. |
| Password | Password of the target instance account. |
Category | Parameter | Description |
Data Initialization Option | Initialization Type | Structure initialization: Table structures in the source instance will be initialized into the target instance before the sync task runs. Full data initialization: Data in the source instance will be initialized into the target database before the sync task runs. Both options are selected by default, and you can deselect them as needed. |
| If Target Already Exists | Precheck and report error: If a table with the same name exists in both the source and target databases, an error will be reported, and the task will stop. Ignore and execute: Full and incremental data will be directly added to tables in the target instance. |
Data Sync Option | Conflict Resolution Method | Report: If a primary key conflict is found during data sync, an error will be reported, and the data sync task will be paused. Ignore: If a primary key conflict is found during data sync, the primary key record in the target database will be retained. Overwrite: If a primary key conflict is found during data sync, the primary key record in the source database will overwrite that in the target database. |
| SQL Type | Supported operations include INSERT, UPDATE, DELETE, and DDL. If you select Custom DDL, you can select different DDL statement sync policies as needed. For more information, see Setting SQL Filter Policy. |
Sync Object Option | Database and Table Objects of Source Instance | Select the objects to be synced. You can select basic databases, tables, views, procedures, and functions.The sync of advanced objects is a one-time operation: only advanced objects already in the source database before the task start can be synced, while those added to the source database after the task start will not be synced to the target database. For more information, see Syncing Advanced Object. |
| Selected Object | Database/Table mapping (renaming) is supported. Hover over a database or table name, click the displayed Edit icon, and enter a new name in the pop-up window. When advanced objects are selected for sync, we recommend you not rename databases/tables; otherwise, sync of the advanced objects may fail. Online DDL temp tables can be synced (through tools such as gh-ost or pt-online-schema-change). Click Edit of a table and select a temp table name in the pop-up window. For more information, see Syncing Online DDL Temp Table. |
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