Sign Up to our social questions and Answers Engine to ask questions, answer people’s questions, and connect with other people.
Login to our social questions & Answers Engine to ask questions answer people’s questions & connect with other people.
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Please briefly explain why you feel this question should be reported.
Please briefly explain why you feel this answer should be reported.
Please briefly explain why you feel this user should be reported.
In the following screenshot, SSMS only copies rows for ONE given table at a time :
It is clearly able to perform multiple copies at a time (in which case you would see several “Copying rows” lines).
What determines the level of parallelism whiles SSMS copies tables ?
The answer lies in the SSIS package that is created behind the wizard. By default this package is created with each data flow task being run sequentially, you can tell this because each task is connected directly to the next with precedence constraints. If you were to save the package, open it in BIDS and remove the precedence constraints, then it would import them in parallel.
The next level would involve database design. SQL Server can only open one IO thread per IO path (generally a LUN or RAID array), so true parallelism would be limited by the number of cores and the number of discs that your tables are spread over.
Beyond that, you have the risk of parallelism being reduced by the external SSIS process(s) fighting for resource with the SQL Server Database Engine.