In this case I started the refresh from the Power BI portal so the default parallelism settings were used. The y axis on this graph shows there were six processing slots available, which means that six objects could be refreshed in parallel – and because there are nine partitions in the only table in the dataset, this in turn meant that some slots had to refresh two partitions. Overall the dataset took 33 seconds to refresh.
However, if you connect from SQL Server Management Studio to the dataset via the workspace’s XMLA Endpoint (it’s very similar to how you connect Profiler, something I blogged about here) you can construct a TMSL script to refresh these partitions with more parallelism.
Read on to see how you can do this, as well as the net improvement.