Rename ExecutionConfig with_concurrency to with_partitions #684
Description
Is your feature request related to a problem or challenge? Please describe what you are trying to do.
Following on from the discussion in apache/datafusion-ballista#20, we are conflating the terms concurrency and partitioning in DataFusion and should make some changes around this.
Describe the solution you'd like
The with_concurrency method in the execution context config builder is really referring to the number of partitions to use, rather than concurrency, and should therefore be renamed to something like with_partitions.
Currently, there is a one to one mapping between concurrency and partitions in some places in query execution, but this is likely to change over time. Ballista has a very different mapping from concurrency to partitions because of the scheduler approach, for example.
Describe alternatives you've considered
None
Additional context
None