SQL Server Migration Synchronization to PostgreSQL

NineData replication supports data synchronization between SQL Server and PostgreSQL data sources.

Feature Introduction

NineData data replication supports high-performance replication of structure, full data, and incremental data between data sources. For certain data sources, it also provides bidirectional replication, enabling the quick construction of geo-distributed active-active business architectures.

• Structure: Supports the replication of object structures between homogeneous and heterogeneous data sources, greatly reducing the barrier to data replication between two sources.
• Full Data: Achieves row-level concurrent batch replication through intelligent data sharding, effectively ensuring replication performance. The independently developed novel breakpoint resume technology ensures the accuracy of data in tables without primary keys.
• Incremental Data: Supports DML and DDL incremental data replication for all object types. By leveraging technologies such as row-level concurrency and hotspot merging, it delivers robust replication performance.
• Bidirectional Real-time Data Replication (only between MySQL instances): Direct bidirectional replication of data between multiple nodes ensures that all node data remains up-to-date.

With the above features, it is easy and efficient to achieve scenarios such as full|incremental data replication, full|incremental data migration, full|incremental data synchronization, data integration, and seamless migration without downtime, providing enterprises with flexible and reliable data replication solutions.

Prerequisites

• The source and target data sources have been added to NineData. For instructions on how to add them, see Adding Data Sources.

• The source data source is SQL Server, with a version of 2022, 2019, 2017, 2016, 2014, 2012, 2008R2, or 2008.

• The target data source is PostgreSQL, with a version of 15, 14, 13, 12, 11, or 10.

• You must have the following permissions for the source and target data sources:

  Replication Type	Source Data Source	Target Data Source
  Full Replication	Read Permission	SELECT, INSERT, UPDATE, DELETE Permissions
  Incremental Replication	Owner Permission	SELECT, INSERT, UPDATE, DELETE Permissions

• SQL Server Agent has been enabled. For instructions on how to enable it, see the official documentation.

Usage Limitations

• Before performing data synchronization, it is necessary to assess the performance of the source and target data sources, and it is recommended to perform data synchronization during off-peak business hours. Otherwise, the full data initialization will occupy a certain amount of read and write resources of the source and target data sources, leading to increased database load.
• It is necessary to ensure that each table in the synchronization object has a primary key or unique constraint, and the column names are unique, otherwise, the same data may be synchronized repeatedly.

Operation Steps

Commercialization Notice

NineData’s data replication product has been commercialized. You can still use 10 replication tasks for free, with the following considerations:

• Among the 10 replication tasks, you can include 1 task, with a specification of Micro.

• Tasks with a status of do not count towards the 10-task limit. If you have already created 10 replication tasks and want to create more, you can terminate previous replication tasks and then create new ones.

• When creating replication tasks, you can only select the you have purchased. Specifications that have not been purchased will be grayed out and cannot be selected. If you need to purchase additional specifications, please contact us through the customer service icon at the bottom right of the page.

1. Log in to the NineData Console.

2. Click on in the left navigation bar.

3. On the page, click on in the top right corner.

4. On the tab, configure according to the table below and click on .

   Parameter	Description
   	Enter the name of the data synchronization task. To facilitate subsequent search and management, please use meaningful names as much as possible. Up to 64 characters are supported.
   	The data source where the synchronization object is located.
   	The data source that receives the synchronization object.
   	Choose the content that needs to be copied to the target data source. : Synchronize all objects and data of the source data source, i.e., full data replication. : After the full synchronization is completed, perform incremental synchronization based on the logs of the source data source.
   	: Stop the task when the target object already exists during the pre-inspection stage. : Ignore and append write when the target object already exists during the pre-inspection stage. : Delete and rewrite when the target object already exists during the pre-inspection stage.

5. On the tab, configure the following parameters, then click on .

   Parameter	Description
   	Choose the content that needs to be copied. You can select to copy all content from the source database, or you can select , select the content that needs to be copied in the list, and click > to add to the right list.

   If you need to create multiple replication chains with the same replication object, you can create a configuration file and import it when creating a new task. Click on in the top right corner, then click Download Template to download the configuration file template to your local machine, edit it, and then click to upload the configuration file to achieve batch import. Configuration file description:

   Parameter	Description
   source_table_name	The source table name where the object to be synchronized is located.
   destination_table_name	The target table name that receives the synchronized object.
   source_schema_name	The source Schema name where the object to be synchronized is located.
   destination_schema_name	The target Schema name that receives the synchronized object.
   source_database_name	The source database name where the object to be synchronized is located.
   target_database_name	The target database name that receives the synchronized object.
   column_list	The list of fields that need to be synchronized.
   extra_configuration	Additional configuration information, where you can configure the following information: Field mapping: column_name, destination_column_name Field value: column_value Data filtering: filter_condition

   tip

   • An example of extra_configuration is as follows:

     {
         "column_name": "created_time", //Specify the original column name for column name mapping
         "destination_column_name": "migrated_time", //Map the target column name to "migrated_time"
         "column_value": "current_timestamp()", //Change the field value of the column to the current timestamp
         "filter_condition": "id != 0" //Only rows with ID not equal to 0 will be synchronized.
     }
     
      - For the overall example content of the configuration file, please refer to the downloaded template.

6. On the tab, the system defaults to selecting the database with the same name in the target data source. If it does not exist, you need to manually select the target database. The table name and column name in the target database need to be consistent with the synchronization object. If they are not consistent, you can also manually map the table name and column name, and then click on . If there are updates in the source and target data sources during the configuration mapping stage, you can click on the button in the top right corner of the page to refresh the information from the source and target data sources.

   You can click on on the right side of the page to customize the name of the column name synchronized to the target data source. In addition, you can set , configure filtering conditions through comparison expressions, and only data that meets the filtering conditions will be synchronized to the target data source. For example, setting the filtering condition to emp_no>=10005 means that data with emp_no column values less than 10005 will not be synchronized to the target data source.

7. On the tab, wait for the system to complete the pre-inspection, and after the pre-inspection is passed, click on .

   tip

   • You can check . After the synchronization task is completed, automatically start data consistency comparison based on the source data source to ensure data consistency on both sides. It starts when the incremental data is first consistent with the source data source and is 0 seconds. You can click on to view the synchronization delay on the page.

     

   • If the pre-inspection does not pass, you need to click on in the column on the right side of the target inspection item, troubleshoot the cause of the failure, manually fix it, and then click on to re-execute the pre-inspection until it passes.

   • If the is for the inspection item, it can be fixed or ignored according to the specific situation.

8. On the page, it prompts , and the synchronization task starts running. At this time, you can perform the following operations:

   • Click on to view the execution of each stage of the synchronization task.
   • Click on to return to the task list page.

Viewing Synchronization Results

1. Log in to the NineData Console.

2. Click on > in the left navigation bar.

3. On the page, click the of the target synchronization task, and the page description is as follows.

   

   No.	Function	Description
   1	Synchronization Delay	The data synchronization delay between the source and target data sources. 0 seconds indicate no delay between the two ends. At this point, you can choose to switch the business to the target data source to achieve a smooth migration.
   2	Configure Alerts	After configuring alerts, the system will notify you through your chosen method when the task fails. For more information, please refer to Introduction to Operations Monitoring.
   3	More	: Pause the task, only available for tasks in the running status. : Create a new replication task with the same configuration as the current task. : End tasks that are not completed or in listening mode (i.e., incremental synchronization). After terminating the task, it cannot be restarted, please proceed with caution. If the synchronization object includes triggers, trigger replication options will pop up, please choose as needed. : Delete the task, the task cannot be recovered after deletion, please proceed with caution.
   4	Full Replication (displayed in scenarios including full replication)	Display the progress and detailed information of full replication. Click on on the right side of the page: View various monitoring metrics during the full replication process. During the full replication process, you can also click on on the right side of the monitoring metrics page to limit the rate of writing to the target data source per second. The unit is rows/second. Click on on the right side of the page: View the execution logs of full replication. Click on the on the right side of the page: View the latest information.
   5	Incremental Replication (displayed in scenarios including incremental replication)	Display various monitoring metrics for incremental replication. Click on on the right side of the page: View the operations currently being executed by the replication task, including: : The replication task is executed by multiple threads, displaying the current thread number. : Details of the SQL statement currently being executed by the current thread. : The response time of the current thread, if this value increases, it indicates that the current thread may be stuck due to some reason. : The timestamp when the current thread started. : The status of the current thread. Click on on the right side of the page: Limit the rate of writing to the target data source per second. The unit is rows/second. Click on on the right side of the page: View the execution logs of incremental replication. Click on the on the right side of the page: View the latest information.
   6	Modify Objects	Display the modification records of synchronization objects. Click on on the right side of the page to configure synchronization objects. Click on the on the right side of the page: View the latest information.
   7	Data Comparison	Display the results of the comparison between the source and target data sources. If you have not enabled data comparison, please click on in the page. Click on on the right side of the page: Re-initiate a comparison between the current source and target data. Click on on the right side of the page: After the comparison task starts, you can click this button to immediately stop the comparison task. Click on on the right side of the page: View the execution logs of consistency comparison. Click on on the right side of the page (only displayed during data comparison): View the trend chart of comparison RPS (records compared per second). Click on to view records from earlier times. Click on in the column on the right side of the comparison list (only displayed under the tab when inconsistencies are found): View the comparison details between the source and target ends. Click on in the column on the right side of the comparison list (displayed when inconsistencies are found): Generate change SQL, you can directly copy this SQL to the target data source for execution, modifying the inconsistent content.
   8	Expand	Display detailed information of the current replication task.

Appendix: Pre-Check Item List

Check Item	Check Content
Source Data Source Connection Check	Check the gateway status of the source data source, instance reachability, and the accuracy of the username and password
Target Data Source Connection Check	Check the gateway status of the target data source, instance reachability, and the accuracy of the username and password
Source Database Permission Check	Check if the account permissions of the source database meet the requirements
Target Database Permission Check	Check if the account permissions of the target database meet the requirements
Source and Target Data Source Version Check	Detect whether the versions of the source database and the target database are compatible
Target Database Data Existence Check	Check if there is data in the target database for the objects to be replicated
Target Database Same Name Object Existence Check	Check if there are existing objects in the target database for the objects to be replicated
Source and Target Data Source Version Check	Detect whether the versions of the source database and the target database are compatible
SQL Server Agent Status Check	Detect whether the SQL Server instance's agent is running

Related Documentation

Introduction to Data Replication