# DD\_for\_SQLServer registry key

The DD\_for\_SQLServer key is available if Talend Change Data Capture for MS SQL Server source module is installed (see [Installing MySQL source](https://help.qlik.com/talend/r/en-US/7.3/change-data-capture-installation-guide/installing-my-sql-source)).

The MS SQL Server database can be installed in multi-instances mode from 8.0 version of MS SQL Server (SQL 2000). For each given instance, you will get one subkey per instance followed by Talend Change Data Capture. This subkey will have the instance name.

| Parameter | Description |
| --- | --- |
| AlwaysOn | To activate the AlwaysOn service. See step 3 in the [Always On availability groups<br>feature](https://help.qlik.com/talend/r/en-US/7.3/change-data-capture-installation-guide/installing-high-availability). |
| AttemptComWait | Period of time before attempting a reconnection between source<br>engine and target engine. This period can be repeated.<br><br>Default<br>value is 30 seconds. |
| **ddSchedulerWait** | Period of time before the Scheduler program relaunches the<br>planning tasks or the tasks that were executed but are not<br>finished yet.<br><br>Default value is 30 seconds. |
| **Maxtrans** | This parameter is used to limit the quantity of transactions that<br>are read in the source database.<br><br>Default value is<br>10000. |
| **PathSQLServerSource** | This parameter contains the path where the programs are<br>installed.<br><br>It is recommended not to modify this parameter. |
| **SpvWait** | This parameter contains the time in seconds between two<br>Supervisor module executions.<br><br>Default value is 30 seconds. |
| Unicode | This key activates and deactivates the unicode parameter, which<br>manages nvarchar data type columns:<br><br><ul> <li><kbd>0</kbd> means the Unicode is not activated                                        (characters are converted to ANSI 1 octet).</li> <li><kbd>1</kbd> means the Unicode is activated                                        (nvachar are stored on 2 octets in the journal).<div><span>Information note</span><span>Note:</span> Issues                                            may arise in the following case: after performing                                            replications with Unicode = 0, you decide to change the                                            value to 1. Before changing the value, contact Talend                                                <a href="https://www.talend.com/technical-support/?_ga=2.177601517.935794220.1683617077-857954988.1641206411" target="_blank">Support</a>                                            team.</div></li> </ul> |
| **Universal** | Default value is 2: LogReader is launched<br>in RedoLog mode.<br><br>It is recommended not to modify this parameter. |
| **WaitBeforeKill** | Period of time (in ms) after the stop command is sent and before<br>the kill command is sent.<br><br>Default value is 1000 ms.<br><br>For more information on how to use this parameter, contact Talend<br>[Support](https://www.talend.com/technical-support/?_ga=2.177601517.935794220.1683617077-857954988.1641206411) team. |