__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,SELECT ON *.* TO 'migration account'@'%' IDENTIFIED BY 'migration password';GRANT ALL PRIVILEGES ON `__tencentdb__`.* TO 'migration account'@'%';FLUSH PRIVILEGES;
Type | Environment Requirements |
Requirements for the source database | The source and target databases can be connected. Requirements for 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 that 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, all tables with foreign key dependency must be migrated. The environment variable innodb_stats_on_metadata must be set to OFF . |
Requirements for the target database | If the target database is a distributed database, we recommend you manually create a partitioned table and plan the shardkey in advance; otherwise, DTS will create a table in the target database based on the table style of the source database. If the source database is a standalone instance, the target database will be created as a single table. 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 max_allowed_packet parameter of the target database must be set to 4 MB or above. |
Parameter | Description |
Billing Mode | Monthly subscription and pay-as-you-go billing are supported. |
Source Instance Type | Select TDSQL for MySQL, which cannot be changed after purchase. TDSQL for MySQL is divided into three kernel versions (MySQL/MariaDB/Percona). Here, select TDSQL for MySQL as there is no need to distinguish the kernel versions. |
Source Instance Region | Select the source region of the DTS task. If the source database is TencentDB, select its region here. If the source database is self-built, select the region closest to it, so that DTS can choose the optimal sycn path to reduce the sycn time. |
Target Instance Type | Select TDSQL for MySQL, which cannot be changed after purchase. |
Target Instance Region | Select the target instance region, which cannot be changed after purchase. |
Specification | Currently, only the Standard Edition is supported. |
Setting Items | 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 | The source database type selected during purchase, which cannot be changed. |
| Source Instance Region | The source instance region selected during purchase, which cannot be changed. |
| 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. For VPN Gateway, select a VPN Gateway instance. |
| Virtual Private Cloud (VPC) | Select a VPC and subnet associated with the VPC-based Direct Connect Gateway or VPN Gateway. |
| Host - Proxy: | Enter the proxy address and port. |
| Node - SET | Enter the TDSQL for MySQL shard node IP. You need to enter a node IP each shard, and separate multiple nodes by line break. If the source database is self-built, when the SET node is configured for the first time, the SET node cannot be added or deleted once the connection is saved. If you need to add or delete the SET node, you need to create the sync task again. |
| 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. If the source instance selects Database for access, the target instance selects "Public Network/Self-Build on CVM/Direct Connect/VPN Access/Database/CCN". |
| Instance ID | Select the ID of the target instance. |
| Account | Account of the target instance, which must have the required permissions. |
| Password | Password of the target instance account. |
Setting Items | 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 instance before the sync task runs. If you select Full data initialization, you need to create the table structure in the target database in advance. Both options are selected by default, and you can deselect them as needed. If you select Full data initialization only, you need to create the table structures in the target database in advance. |
| 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 | Overwrite: If a primary key conflict is found during data sync, the system will use the primary key record in the source database to overwrite that in the target database. |
| SQL Type | The following operations are supported: INSERT, DELETE, UPDATE, and DDL. |
Sync Object Option | Database and Table Objects of Source Instance | Select the objects to be synced. You can select databases and tables. |
| Selected Object | It displays the selected sync objects, and database/table mapping is supported. |
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