From GaussDB Distributed to Kafka¶
Supported Source and Destination Databases¶
Source DB | Destination DB |
|---|---|
|
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Supported Synchronization Objects¶
Table 2 lists the objects that can be synchronized in different scenarios. DRS will automatically check the objects you selected before the synchronization.
Type | Synchronization Scope |
|---|---|
Synchronization scope |
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Database User Permission Requirements¶
Before you start a synchronization task, the source and destination database users must meet the requirements in the following table. Different types of synchronization tasks require different permissions. For details, see Table 3. DRS automatically checks the database account permissions in the pre-check phase and provides handling suggestions.
Note
You are advised to create an independent database account for DRS task connection to prevent task failures caused by account modification.
After changing the account passwords for the source or destination databases, modify the connection information in the DRS task as soon as possible to prevent automatic retry after a task failure. Automatic retry will lock the database accounts.
Type | Incremental |
|---|---|
Source database user | The user has the sysadmin role or the following minimum permissions: The REPLICATION permission or the permission inherited from the built-in role gs_role_replication, the CONNECT permission for databases, the USAGE permission for schemas, and the SELECT permission for tables. |
Suggestions¶
The success of database synchronization depends on environment and manual operations. To ensure a smooth synchronization, perform a synchronization trial before you start the synchronization to help you detect and resolve problems in advance.
It is recommended that you start a task during off-peak hours to minimize the impact of synchronization on your services.
Precautions¶
DRS incremental synchronization consists of three phases: task start, incremental synchronization, and task completion. To ensure smooth synchronization, read the following notes before creating a synchronization task.
Type | Constraints |
|---|---|
Starting a task |
|
Incremental synchronization |
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Stopping a task |
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Prerequisites¶
You have logged in to the DRS console.
For details about the DB types and versions supported by real-time synchronization, see Real-Time Synchronization.
You have read Suggestions and Precautions.
Procedure¶
On the Data Synchronization Management page, click Create Synchronization Task.
On the Create Synchronization Instance page, specify the task name, description, and the synchronization instance details, and click Next.
Table 5 Task and recipient description¶ Parameter
Description
Region
The region where the synchronization instance is deployed. You can change the region.
Project
The project corresponds to the current region and can be changed.
Task Name
The task name must start with a letter and consist of 4 to 50 characters. It can contain only letters, digits, hyphens (-), and underscores (_).
Description
The description consists of a maximum of 256 characters and cannot contain special characters
!=<>'&"\Table 6 Synchronization instance settings¶ Parameter
Description
Data Flow
Select Out of the cloud.
Source DB Engine
Select GaussDB Distributed.
Destination DB Engine
Select Kafka.
Network Type
The public network is used as an example. Available options: Public network and VPN or Direct Connect
Source DB Instance
The distributed GaussDB instance you created.
Synchronization Mode
Incremental
Through log parsing, incremental data generated on the source database is synchronized to the destination database.
During synchronization, the source database continues to provide services for external systems with zero downtime.
Tags
This setting is optional. Adding tags helps you better identify and manage your tasks. Each task can have up to 20 tags.
After a task is created, you can view its tag details on the Tags tab. For details, see Tag Management.
Note
If a task fails to be created, DRS retains the task for three days by default. After three days, the task automatically ends.
On the Configure Source and Destination Databases page, wait until the synchronization instance is created. Then, specify source and destination database information and click Test Connection for both the source and destination databases to check whether they have been connected to the synchronization instance. After the connection tests are successful, click Next.
Establish the connectivity between the DRS instance and the source and destination databases.
Network connectivity: Ensure that the source and destination databases accept connections from the DRS instance.
Account connectivity: Ensure that the source and destination databases allows connections from the DRS instance using the username and password.
Table 7 Source database settings¶ Parameter
Description
DB Instance Name
The distributed GaussDB instance selected during synchronization task creation. This parameter cannot be changed.
Database Username
The username for accessing the source database.
Database Password
The password for the database username.
Note
The username and password of the source database are encrypted and stored in DRS and will be cleared after the task is deleted.
Table 8 Destination database settings¶ Parameter
Description
IP Address or Domain Name
IP address or domain name of the destination database in the IP address/Domain name:Port format. The port of the destination database. Range: 1 - 65535
You can enter up to 10 groups of IP addresses or domain names of the source database. Separate multiple values with commas (,). For example: 192.168.0.1:8080,192.168.0.2:8080.
Method
Available options: PLAINTEXT, SSL, SASL_PLAINTEXT, and SASL_SSL. For details, see Kafka Authentication.
On the Set Synchronization Task page, select the synchronization policy, objects, and data format, and click Next.
Table 9 Synchronization Object¶ Parameter
Description
Source Database Replication Slot Name
You can choose whether to specify the replication slot of the source database. After replication slot is enabled, enter the replication slot name. The name contains 63 characters and cannot start with a digit. Only lowercase letters, digits, and underscores (_) are allowed.
Topic Synchronization Policy
Topic synchronization policy. You can select A specific topic or Auto-generated topics.
Topic
Select the topic to be synchronized to the destination database. This parameter is available when the topic is set to A specified topic.
Topic Name Format
This parameter is available when Topic Synchronization Policy is set to Auto-generated topics.
Number of Partitions
This parameter is available when Topic Synchronization Policy is set to Auto-generated topics.
The number of partitions of a topic. Each topic can have multiple partitions. More partitions can provide higher throughput but consume more resources. Set the number of partitions based on the actual situation of brokers.
Replication Factor
This parameter is available when Topic Synchronization Policy is set to Auto-generated topics.
Number of copies of a topic. Each topic can have multiple copies, and the copies are placed on different brokers in a cluster. The number of copies cannot exceed the number of brokers. Otherwise, the topic fails to be created.
Synchronize Topic To
The policy for synchronizing topics to the Kafka partitions.
If topics are synchronized to different partitions by hash value of the database, schema and table names, the performance on a single table query can be improved.
If topics are synchronized to different partitions by hash value of the primary key, one table corresponds to one topic. This prevents data from being written to the same partition, and consumers can obtain data from different partitions concurrently.
For a table without a primary key, if you select Partitions are identified by the hash values of the primary key, topics are synchronized to different partitions based on the hash value of the database_name.schema.table_name.
Partitions are differentiated by the hash values of database_name.schema_name: This mode applies to scenarios where one database corresponds to one topic, preventing multiple schemas from being written to the same partition, so that consumers can obtain data from different partitions concurrently.
If topics are synchronized to partition 0, strong consistency can be obtained but write performance is impacted.
Data Format in Kafka
Select the data format to be delivered to Kafka.
Avro refers to binary encoded format.
JSON: JSON message format, which is easy to interpret but takes up more space.
For details, see Kafka Message Format.
Synchronization Object
DRS supports table-level synchronization. You can select data for synchronization based on your service requirements.
Note
You can search for table names to quickly select the required database objects.
If there are changes made to the source databases or objects, click in the upper right corner to update the objects to be synchronized.
If an object name contains spaces, the spaces before and after the object name are not displayed. If there are two or more consecutive spaces in the middle of the object name, only one space is displayed.
The name of the selected synchronization object cannot contain spaces.
On the Check Task page, check the synchronization task.
If any check fails, review the cause and rectify the fault. After the fault is rectified, click Check Again.
If all check items are successful, click Next.
Note
You can proceed to the next step only when all checks are successful. If there are any items that require confirmation, view and confirm the details first before proceeding to the next step.
On the Confirm Task page, specify Start Time, confirm that the configured information is correct, and click Submit to submit the task.
Table 10 Task startup settings¶ Parameter
Description
Started Time
Set Start Time to Start upon task creation or Start at a specified time based on site requirements.
Note
After a synchronization task is started, the performance of the source and destination databases may be affected. You are advised to start a synchronization task during off-peak hours.
After the task is submitted, you can view and manage it on the Data Synchronization Management page.
You can view the task status. For more information about task status, see Task Statuses.
You can click
in the upper-right corner to view the latest task status.By default, DRS retains a task in the Configuration state for three days. After three days, DRS automatically deletes background resources, but the task status remains unchanged. When you reconfigure the task, DRS applies for resources for the task again.