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Thread: Parallell Process Streams

  1. #1
    Join Date
    May 2007

    Default Parallell Process Streams

    I am reading data from my staging file. The file contains data for a fact. I am looking up dimensions to get the technical keys. I have to look up abut 10 dimensions. Is there a difference in performance if I do the look ups one after another or if I do the lookups in parallel (by copping the same row to different lines). Are different lines multi threaded?


  2. #2
    Join Date
    May 2006


    If you only do lookup it should work in parallel (pick the right copy/distribution mode of the hops)... and keep in mind that the order of the rows afterwards is undetermined.
    In transformations every step runs concurrently in its own thread.

    Personal experience is that it's better to pipeline them... use them in sequence. I start parallellizing stuff after I expect more than 400.000 a 500.000 rows.


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