Let us learn more about the CDC replication SQL server. With the support of our MSSQL support services at Bobcares, let us take a closer look at how to set it up.

SQL Server Change Data Capture (CDC) for real-time SQL Server Replication

This blog discusses SQL Server CDC, what it is, the benefits and drawbacks of SQL Server CDC, how to activate SQL Server CDC step by step, how to optimize SQL Server CDC performance, and why we should consider automated SQL Server CDC.

What is SQL Server CDC?

SQL Server Change Data Capture, sometimes known as CDC, is a method of recording all changes made to a Microsoft SQL Server database. I will record, any inserts, changes, or deletes done to any of the tables during a certain time frame. It will also record the changes to table structures, making this data available for SQL Server replication.

Change data capture (CDC) examines transaction logs to detect data changes and captures them in a separate table or database. This has little impact on server resources but has no effect on the tables themselves. Unlike SQL Server Change tracking, there are no locks, reads, or other things that might block or slow down transactions.

What are the advantages of the CDC?

CDC, as opposed to bulk load updates to sync data, has many advantages when duplicating a data source:

1. Fast. As the CDC copies just the rows that change from the source database, the replication procedure will complete faster.
2. Less burden on the network. CDC transfers less data – only the rows that have changed – over the network from the source to the replica, reducing the pressure on your bandwidth.
3. Less burden on the production database. When CDC is correct, the replication processes have no effect on the production database. Instead of locking committed transactions until the replication is complete, this frees resources for transactions.
4. Synchronous replication. CDC can for real-time data integration, allowing us to create streaming analytics or replication with almost no latency.
5. Flexible. CDC can adapt to changes in database and table schemas, adapt to data modifications and propagate updates from data producers to data consumers.

How does change data capture work?

Change data capture discovers rows that have changed in source tables since the last replication.

It replicates data transactional changes, such as adding new data to a table, modifying current data, or removing old data. These are the create-update-delete (CUD) operations, often known as INSERT, UPDATE, and DELETE in SQL.

Furthermore, CDC detects changes in metadata, such as schema migrations (column name changes, the addition of attributes to tables, and so on), and adapts the target database to accommodate the schema changes.

There are several approaches to adopting CDC. The implementation specifics have an impact on the CDC replication’s efficiency.

How to enable CDC in SQL Server – step by step?

Use the following command line to activate Change Data Capture (CDC):

1. At DB level:

Use ;
EXEC sys.sp_cdc_enable_db;

For Example:

Use Abcd;
EXEC sys.sp_cdc_enable_db;

2. At table level:

To enable SQL Change Data Capture on a Table in SQL Server, type in the following:

databasename
GO
EXEC sys.sp_cdc_enable_table
@source_schema = ‘schema_name’,
@source_name = ‘table_name’,
@role_name = null,
@supports_net_changes = 0;

For example:

USE Abcd
GO
EXEC sys.sp_cdc_enable_table
@source_schema = ‘dbo’,
@source_name = ‘DimCustomer’,
@role_name = null,
@supports_net_changes = 0;

How to check if CDC is enabled on a table in SQL Server?

1. To determine this use the command line given below:

USE master
GO
select name, is_cdc_enabled
from sys.databases
where name = ‘’
GO

For example:

USE Abcd
GO

select name, is_cdc_enabled
from sys.databases where name = ‘Abcd’
GO

Results

name is-cdc-enabled
abcd 1

If is_cdc_enabled is 0 then CDC is not active for the database.

If is_cdc_enabled is 1 then CDC is already active for the database name.

2. We can use the following command line to see if CDC is enabled at the table level:

USE databasename
GO
select name,type,type_desc,is_tracked_by_cdc
from sys.tables
where name = ‘table_name’
GO

For example:

USE Adventureworks
GO
select name,type,type_desc,is_tracked_by_cdc
from sys.tables
where name = ‘DimCustomer’
GO.

Results

If is_tracked_by_cdc = 1 then CDC is enabled for the table.

If is_tracked_by_cdc = 0 then CDC is not enabled for the table.

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Conclusion

To conclude, we have learned how to CDC replication SQL server. With the support of our MSSQL support services, we have gone through all of the steps.