Table API table2datastream (toChangelogStream)

[ravi_suryavanshi.yahoo.com via user]

Hi,I am trying to use the Table API which will convert the Table data into 
Datastream. API is StreamTableEnvironment.toChangelogStream(Table table).I have 
noticed that its parallelism is always single i.e. One (1). How can set more 
than one?
If it is intended to execute with a single thread then is there any impact on 
scalability and performance?
Thanks and Regards,Ravi