This topic describes how to use Data Transmission Service (DTS) to synchronize data
from a user-created MySQL database connected by a leased line, VPN Gateway, or Smart
Access Gateway to an AnalyticDB for PostgreSQL instance. DTS facilitates data transmission
and the centralized analysis of enterprise data.
Prerequisites
- The version of the user-created MySQL database is 5.1, 5.5, 5.6, 5.7, or 8.0.
- The tables to be synchronized from the source database contain primary keys.
- The binary logging feature is enabled for the source database. A database account
is created for the data synchronization task. For more information, see Create an account for a user-created MySQL database and configure binary logging.
Note The account must have the REPLICATION SLAVE permission, the REPLICATION CLIENT permission,
and the permission to perform SELECT operations on the required objects.
- The on-premises network to which the user-created MySQL database belongs is connected
to Alibaba Cloud VPC over Express Connect, VPN Gateway, or Smart Access Gateway. DTS
is allowed to access the network to which Express Connect, VPN Gateway, or Smart Access
Gateway belongs. For more information, see Allow DTS to access the network connected over Express Connect, VPN Gateway, or Smart Access Gateway.
Note For more information about how to connect a VPC to an on-premises data center, see
Connect to local IDCs.
- An AnalyticDB for PostgreSQL instance is created. For more information, see Create an instance.
Notes
DTS uses read and write resources of the source and destination databases during initial
full data synchronization. This may increase the database load. If the database performance
is unfavorable, the specification is low, or the data volume is large, database services
may become unavailable. For example, DTS occupies a large amount of read and write
resources in the following cases: a large number of slow SQL queries are performed
on the source database, the tables have no primary keys, or a deadlock occurs in the
destination database. Before synchronizing data, you must evaluate the performance
of the source and destination databases. We recommend that you synchronize data during
off-peak hours. For example, you can synchronize data when the CPU loads of the source
and destination databases are less than 30%.
Limits
- You can select only tables as the objects to be synchronized.
- You cannot synchronize the following types of data: BIT, VARBIT, GEOMETRY, ARRAY,
UUID, TSQUERY, TSVECTOR, and TXID_SNAPSHOT.
- We recommend that you do not use gh-ost or pt-online-schema-change to perform DDL
operations on objects during data synchronization. Otherwise, data synchronization
may fail.
Supported SQL operations
- DML operations: INSERT, UPDATE, and DELETE
- DDL operations: ADD COLUMN, and RENAME COLUMN
Supported synchronization topologies
- One-way one-to-one synchronization
- One-way one-to-many synchronization
- One-way many-to-one synchronization
Term mappings
Term in MySQL |
Term in AnalyticDB for PostgreSQL |
Database |
Schema |
Table |
Table |
Procedure
- Purchase a data synchronization instance. For more information, see Purchase procedure.
Note On the purchase page, select MySQL for the source instance and AnalyticDB for PostgreSQL for the destination instance. Select One-Way Synchronization as the synchronization topology.
- Log on to the DTS console.
- In the left-side navigation pane, click Data Synchronization.
- At the top of the Synchronization Tasks page, select the region where the destination instance resides.
- Find the data synchronization instance and click Configure Synchronization Channel in the Actions column.
- Configure the source and destination instances.
Section |
Parameter |
Description |
Synchronization Task Name |
N/A |
DTS automatically generates a task name. We recommend that you use an informative
name for easy identification. You do not need to use a unique task name.
|
Source Instance Details |
Instance Type |
Select User-Created Database Connected over Express Connect, VPN Gateway, or Smart Access
Gateway.
|
Instance Region |
The region of the source instance. The value is the same as that you selected when
purchasing the data synchronization instance. You cannot change the value of this
parameter.
|
Peer VPC |
Select the ID of the VPC that is connected to the user-created MySQL database. |
Database Type |
The value of this parameter is set to MySQL and cannot be changed.
|
IP Address |
Enter the server IP address of the user-created MySQL database. |
Port Number |
Enter the service port number of the user-created MySQL database. The default port
number is 3306.
|
Database Account |
Enter the account for the user-created MySQL database.
Note The account must have the REPLICATION SLAVE permission, the REPLICATION CLIENT permission,
and the permission to perform SELECT operations on the required objects.
|
Database Password |
Enter the password for the database account. |
Destination Instance Details |
Instance Type |
The value of this parameter is set to AnalyticDB for PostgreSQL and cannot be changed.
|
Instance Region |
The region of the destination instance. The value is the same as that you selected
when purchasing the data synchronization instance. You cannot change the value of
this parameter.
|
Instance ID |
Select the ID of the destination AnalyticDB for PostgreSQL instance. |
Database Name |
Enter the name of the destination database. |
Database Account |
Enter the database account for the destination AnalyticDB for PostgreSQL instance.
Note The database account must have the SELECT, INSERT, UPDATE, DELETE, COPY, TRUNCATE,
and ALTER TABLE permissions.
|
Database Password |
Enter the password for the database account. |
- In the lower-right corner of the page, click Set Whitelist and Next.
Note The CIDR blocks of DTS servers are automatically added to the whitelist of the destination
AnalyticDB for PostgreSQL instance. This ensures that DTS servers can connect to the
destination AnalyticDB for PostgreSQL instance.
- Configure the synchronization policy and objects.
Section |
Parameter |
Description |
Synchronization policy |
Initial Synchronization |
You must select both Initial Schema Synchronization and Initial Full Data Synchronization in most cases. After the precheck, DTS synchronizes the schemas and data of the required
objects from the source instance to the destination instance. The schemas and data
are the basis for subsequent incremental synchronization.
|
Processing Mode In Existed Target Table |
- Clear Target Table
Skips the Schema Name Conflict item during the precheck. Clears the data in the destination table before initial
full data synchronization. If you want to synchronize your business data after testing
the data synchronization task, you can select this mode.
- Ignore
Skips the Schema Name Conflict item during the precheck. Adds new data to the existing data during initial full
data synchronization. You can select this mode if you want to synchronize data from
multiple tables to one table.
|
Synchronization Type |
Select the types of operations that you want to synchronize based on your business
requirements.
- Insert
- Update
- Delete
- Alter Table
|
Objects to be synchronized |
N/A |
Select tables from the Available section and click the right arrow ( ) icon to add the tables to the Selected section.
Note
- You can select only tables as the objects to be synchronized.
- You can change the names of columns in the destination database by using the object
name mapping feature provided by DTS. For more information about how to use this feature,
see Specify the name of an object in the destination instance.
|
- Specify the primary key column and distribution column of the table that you want
to synchronize to the AnalyticDB for PostgreSQL instance.
Note The page in this step appears only if you select Initial Schema Synchronization.
- In the lower-right corner of the page, click Precheck.
Note
- Before you can start the data synchronization task, a precheck is performed. You can
start the data synchronization task only after the task passes the precheck.
- If the task fails to pass the precheck, click the
icon next to each failed item to view details. Troubleshoot the issues based on the
causes and run the precheck again.
- Close the Precheck dialog box after the following message is displayed: The precheck is passed.
- Wait until the initial synchronization is complete and the data synchronization task
is in the Synchronizing state.
On the
Synchronization Tasks page, view the status of the data synchronization task.
