Pivot stage - Parallel mode
Posted: Wed Mar 19, 2008 11:57 pm
Hi,
I ready many thread on the pivot stage in parallel and the performance issue.
I created one temp job and tested it in parallel mode and seq mode. As expected the PX performance was better.
In PX mode, I kept the partitioning to auto.
Many of the threads mentioned that the pivot stage needs hash on pivot keys. The pivot documentation that I have does not talk abt partitioning for the stage or PX or Seq mode.
Though the pivot stage functionality is simple i.e. convert one row into multiple based on the input cols, just wondering why does it need hash partitioning?
E.g.
If input is:
It has to generate the following output
I also tried running the same job with RR partion and it produced the same no. of rows. The output was also the same.
Any thoughts?
I ready many thread on the pivot stage in parallel and the performance issue.
I created one temp job and tested it in parallel mode and seq mode. As expected the PX performance was better.
In PX mode, I kept the partitioning to auto.
Many of the threads mentioned that the pivot stage needs hash on pivot keys. The pivot documentation that I have does not talk abt partitioning for the stage or PX or Seq mode.
Though the pivot stage functionality is simple i.e. convert one row into multiple based on the input cols, just wondering why does it need hash partitioning?
E.g.
If input is:
Code: Select all
EmpNo Error1 Error2 Error3
1001 Er1 Er2 Er3
1002 Er4 Er5 Er6
1001 Er1 Er4 Er5
Code: Select all
EmpNo Error
1001 Er1
1001 Er2
1001 Er3
1002 Er4
1002 Er5
1002 Er6
1001 Er1
1001 Er4
1001 Er5
Any thoughts?