In SQL Server Integration Services (SSIS) projects, it is common to encounter situations where data flow tasks running in parallel and transferring large volumes of data experience a decrease in transfer speed, impacting the overall process. This can lead to resource contention and reduced productivity in the ETL process.

In this blog post, we will discuss an approach to stop a data flow task in the middle of the process without canceling the execution of the entire SSIS package. This approach allows for more control and flexibility in managing data flow tasks.

General Approach

The general approach involves interrupting the execution of a specific data flow task when its data transfer speed is significantly slower than expected. This interruption is triggered by updating a control table, which in turn stops the data flow task from running. Other processes can continue to run at a faster pace, as additional server resources are released.

To measure the data transfer speed and determine when to interrupt a data flow task, various methods can be used. The key is to identify the critical threshold and trigger the interruption at the right moment.

Implementation

Let’s take a look at the implementation steps:

1. Create a control table that allows for stopping the data flow task. This table should include columns such as ETLstatus, StopDelay, StopInd, ETLstart, ETLstop, ETLruntTime, and RecordsTransferred.
2. In the SSIS package, include a control flow that interacts with the control table. This control flow should include tasks such as truncating the destination table, updating the control table to indicate the start of the ETL process, and running a stored procedure to trigger the interruption.
3. In the data flow, include components such as an OLEDB Source, a Stop Command component, and an OLEDB Destination. The Stop Command component checks the status of the control table and throws an error if there is a request to stop the process.
4. Execute the SSIS package and observe the results. The data flow task will be interrupted if the conditions specified in the control table are met.

Conclusion

This approach provides a way to easily interrupt a data flow task in SSIS based on specific conditions. By leveraging a control table and implementing the necessary components and tasks, you can have more control over the execution of data flow tasks and optimize the overall ETL process.

Remember to set the appropriate error handling properties to avoid package failure and ensure that errors within the data flow task are not propagated to upper levels.

By implementing this approach, you can enhance the performance and efficiency of your SSIS projects, especially when dealing with large volumes of data and parallel data flow tasks.