Microsoft SQL Server (MSSQL)
Airbyte's certified MSSQL connector offers the following features:
- Multiple methods of keeping your data fresh, including Change Data Capture (CDC) using the binlog.
- Incremental as well as Full Refresh sync modes, providing flexibility in how data is delivered to your destination.
- Reliable replication at any table size with checkpointing and chunking of database reads.
⚠️ Please note the minimum required platform version is v0.58.0 to run source-mssql 4.0.18 and above.
Features
Feature | Supported | Notes |
---|---|---|
Full Refresh Sync | Yes | |
Incremental Sync - Append | Yes | |
Replicate Incremental Deletes | Yes | |
CDC (Change Data Capture) | Yes | |
SSL Support | Yes | |
SSH Tunnel Connection | Yes | |
Namespaces | Yes | Enabled by default |
The MSSQL source does not alter the schema present in your database. Depending on the destination connected to this source, however, the schema may be altered. See the destination's documentation for more details.
Getting Started
Requirements
- MSSQL Server
Azure SQL Database
,Azure Synapse Analytics
,Azure SQL Managed Instance
,SQL Server 2022
,SQL Server 2019
,SQL Server 2017
,SQL Server 2016
,SQL Server 2014
,SQL Server 2012
,PDW 2008R2 AU34
. - Create a dedicated read-only Airbyte user with access to all tables needed for replication
- If you want to use CDC, please see the relevant section below for further setup requirements
1. Make sure your database is accessible from the machine running Airbyte
This is dependent on your networking setup. The easiest way to verify if Airbyte is able to connect to your MSSQL instance is via the check connection tool in the UI.
2. Create a dedicated read-only user with access to the relevant tables (Recommended but optional)
This step is optional but highly recommended to allow for better permission control and auditing. Alternatively, you can use Airbyte with an existing user in your database.
3. Your database user should now be ready for use with Airbyte!
Airbyte Cloud
On Airbyte Cloud, only secured connections to your MSSQL instance are supported in source configuration. You may either configure your connection using one of the supported SSL Methods or by using an SSH Tunnel.
Change Data Capture (CDC)
We use
SQL Server's change data capture feature
with transaction logs to capture row-level INSERT
, UPDATE
and DELETE
operations that occur on
CDC-enabled tables.
Some extra setup requiring at least db_owner permissions on the database(s) you intend to sync from will be required (detailed below).
Please read the CDC docs for an overview of how Airbyte approaches CDC.
Should I use CDC for MSSQL?
- If you need a record of deletions and can accept the limitations posted below, CDC is the way to go!
- If your data set is small and/or you just want a snapshot of your table in the destination, consider using Full Refresh replication for your table instead of CDC.
- If the limitations below prevent you from using CDC and your goal is to maintain a snapshot of your table in the destination, consider using non-CDC incremental and occasionally reset the data and re-sync.
- If your table has a primary key but doesn't have a reasonable cursor field for incremental syncing
(i.e.
updated_at
), CDC allows you to sync your table incrementally.
CDC Limitations
- Make sure to read our CDC docs to see limitations that impact all databases using CDC replication.
hierarchyid
andsql_variant
types are not processed in CDC migration type (not supported by Debezium). For more details please check this ticket- CDC is only available for SQL Server 2016 Service Pack 1 (SP1) and later.
- db_owner (or higher) permissions are required to perform the neccessary setup for CDC.
- On Linux, CDC is not supported on versions earlier than SQL Server 2017 CU18 (SQL Server 2019 is supported).
- Change data capture cannot be enabled on tables with a clustered columnstore index. (It can be enabled on tables with a non-clustered columnstore index).
- The SQL Server CDC feature processes changes that occur in user-created tables only. You cannot enable CDC on the SQL Server master database.
- Using variables with partition switching on databases or tables with change data capture (CDC)
is not supported for the
ALTER TABLE
...SWITCH TO
...PARTITION
... statement. - CDC incremental syncing is only available for tables with at least one primary key. Tables without primary keys can still be replicated by CDC but only in Full Refresh mode. For more information on CDC limitations, refer to our CDC Limitations doc.
- Our CDC implementation uses at least once delivery for all change records.
- Read more on CDC limitations in the Microsoft docs.
Setting up CDC for MSSQL
1. Enable CDC on database and tables
MS SQL Server provides some built-in stored procedures to enable CDC.
-
To enable CDC, a SQL Server administrator with the necessary privileges (db_owner or sysadmin) must first run a query to enable CDC at the database level.
USE {database name}
GO
EXEC sys.sp_cdc_enable_db
GO -
The administrator must then enable CDC for each table that you want to capture. Here's an example:
USE {database name}
GO
EXEC sys.sp_cdc_enable_table
@source_schema = N'{schema name}',
@source_name = N'{table name}',
@role_name = N'{role name}', [1]
@filegroup_name = N'{filegroup name}', [2]
@supports_net_changes = 0 [3]
GO- [1] Specifies a role which will gain
SELECT
permission on the captured columns of the source table. We suggest putting a value here so you can use this role in the next step but you can also set the value of @rolename toNULL
to allow only _sysadmin and db_owner to have access. Be sure that the credentials used to connect to the source in Airbyte align with this role so that Airbyte can access the cdc tables. - [2] Specifies the filegroup where SQL Server places the change table. We recommend creating a separate filegroup for CDC but you can leave this parameter out to use the default filegroup.
- [3] If 0, only the support functions to query for all changes are generated. If 1, the functions that are needed to query for net changes are also generated. If supports_net_changes is set to 1, index_name must be specified, or the source table must have a defined primary key.
- [1] Specifies a role which will gain
-
(For more details on parameters, see the Microsoft doc page for this stored procedure).
-
If you have many tables to enable CDC on and would like to avoid having to run this query one-by-one for every table, this script might help!
For further detail, see the Microsoft docs on enabling and disabling CDC.
2. Enable snapshot isolation
-
When a sync runs for the first time using CDC, Airbyte performs an initial consistent snapshot of your database. To avoid acquiring table locks, Airbyte uses snapshot isolation, allowing simultaneous writes by other database clients. This must be enabled on the database like so:
ALTER DATABASE {database name}
SET ALLOW_SNAPSHOT_ISOLATION ON;
3. Create a user and grant appropriate permissions
-
Rather than use sysadmin or db_owner credentials, we recommend creating a new user with the relevant CDC access for use with Airbyte. First let's create the login and user and add to the db_datareader role:
USE {database name};
CREATE LOGIN {user name}
WITH PASSWORD = '{password}';
CREATE USER {user name} FOR LOGIN {user name};
EXEC sp_addrolemember 'db_datareader', '{user name}';-
Add the user to the role specified earlier when enabling cdc on the table(s):
EXEC sp_addrolemember '{role name}', '{user name}';
-
This should be enough access, but if you run into problems, try also directly granting the user
SELECT
access on the cdc schema:USE {database name};
GRANT SELECT ON SCHEMA :: [cdc] TO {user name}; -
If feasible, granting this user 'VIEW SERVER STATE' permissions will allow Airbyte to check whether or not the SQL Server Agent is running. This is preferred as it ensures syncs will fail if the CDC tables are not being updated by the Agent in the source database.
USE master;
GRANT VIEW SERVER STATE TO {user name};
-
4. Extend the retention period of CDC data
-
In SQL Server, by default, only three days of data are retained in the change tables. Unless you are running very frequent syncs, we suggest increasing this retention so that in case of a failure in sync or if the sync is paused, there is still some bandwidth to start from the last point in incremental sync.
-
These settings can be changed using the stored procedure sys.sp_cdc_change_job as below:
-- we recommend 14400 minutes (10 days) as retention period
EXEC sp_cdc_change_job @job_type='cleanup', @retention = {minutes} -
After making this change, a restart of the cleanup job is required:
EXEC sys.sp_cdc_stop_job @job_type = 'cleanup';
EXEC sys.sp_cdc_start_job @job_type = 'cleanup';
- If you were are using Transaction Replication then the retention has to be changed using below scripts :
EXEC sp_changedistributiondb
@database = 'distribution',
@property = 'max_distretention',
@value = 14400 -- 14400 minutes (10 days)
EXEC sp_changedistributiondb
@database = 'distribution',
@property = 'history_retention',
@value = 14400 -- 14400 minutes (10 days)
USE [msdb]
GO
EXEC msdb.dbo.sp_update_jobstep @job_name=N'Distribution clean up: distribution', @step_id=1 ,
@command=N'EXEC dbo.sp_MSdistribution_cleanup @min_distretention = 0, @max_distretention = 14400'
GO
5. Ensure the SQL Server Agent is running
-
MSSQL uses the SQL Server Agent
for CDC. It is therefore vital that the Agent is operational in order for to CDC to work effectively. You can check
the status of the SQL Server Agent as follows:
EXEC xp_servicecontrol 'QueryState', N'SQLServerAGENT';
-
If you see something other than 'Running.' please follow
the Microsoft docs
to start the service.
Connection to MSSQL via an SSH Tunnel
Airbyte has the ability to connect to a MSSQL instance via an SSH Tunnel. The reason you might want to do this because it is not possible (or against security policy) to connect to the database directly (e.g. it does not have a public IP address).
When using an SSH tunnel, you are configuring Airbyte to connect to an intermediate server (a.k.a. a bastion sever) that does have direct access to the database. Airbyte connects to the bastion and then asks the bastion to connect directly to the server.
Using this feature requires additional configuration, when creating the source. We will talk through what each piece of configuration means.
-
Configure all fields for the source as you normally would, except
SSH Tunnel Method
. -
SSH Tunnel Method
defaults toNo Tunnel
(meaning a direct connection). If you want to use anSSH Tunnel choose
SSH Key Authentication
orPassword Authentication
.-
Choose
Key Authentication
if you will be using an RSA private key as your secret forestablishing the SSH Tunnel (see below for more information on generating this key).
-
Choose
Password Authentication
if you will be using a password as your secret for establishingthe SSH Tunnel.
-
-
SSH Tunnel Jump Server Host
refers to the intermediate (bastion) server that Airbyte will connect to. This shouldbe a hostname or an IP Address.
-
SSH Connection Port
is the port on the bastion server with which to make the SSH connection. The default port forSSH connections is
22
, so unless you have explicitly changed something, go with the default. -
SSH Login Username
is the username that Airbyte should use when connection to the bastion server. This is NOT theMSSQL username.
-
If you are using
Password Authentication
, thenSSH Login Username
should be set to thepassword of the User from the previous step. If you are using
SSH Key Authentication
leave thisblank. Again, this is not the MSSQL password, but the password for the OS-user that Airbyte is
using to perform commands on the bastion.
-
If you are using
SSH Key Authentication
, thenSSH Private Key
should be set to the RSAprivate Key that you are using to create the SSH connection. This should be the full contents of
the key file starting with
-----BEGIN RSA PRIVATE KEY-----
and endingwith
-----END RSA PRIVATE KEY-----
.
Generating an SSH Key Pair
The connector expects an RSA key in PEM format. To generate this key:
ssh-keygen -t rsa -m PEM -f myuser_rsa
This produces the private key in pem format, and the public key remains in the standard format used
by the authorized_keys
file on your bastion host. The public key should be added to your bastion
host to whichever user you want to use with Airbyte. The private key is provided via copy-and-paste
to the Airbyte connector configuration screen, so it may log in to the bastion.
Data type mapping
MSSQL data types are mapped to the following data types when synchronizing data. You can check the test values examples here. If you can't find the data type you are looking for or have any problems feel free to add a new test!
MSSQL Type | Resulting Type | Notes |
---|---|---|
bigint | number | |
binary | string | |
bit | boolean | |
char | string | |
date | date | |
datetime | timestamp | |
datetime2 | timestamp | |
datetimeoffset | timestamp with timezone | |
decimal | number | |
int | number | |
float | number | |
geography | string | |
geometry | string | |
money | number | |
numeric | number | |
ntext | string | |
nvarchar | string | |
nvarchar(max) | string | |
real | number | |
smalldatetime | timestamp | |
smallint | number | |
smallmoney | number | |
sql_variant | string | |
uniqueidentifier | string | |
text | string | |
time | time | |
tinyint | number | |
varbinary | string | |
varchar | string | |
varchar(max) COLLATE Latin1_General_100_CI_AI_SC_UTF8 | string | |
xml | string |
If you do not see a type in this list, assume that it is coerced into a string. We are happy to take feedback on preferred mappings.