In a parallel job a unique counter is generated by using special parallel macros.
1. Create a stage variable for the counter, eg. SVCounter.
2. At the Stage Properties form set the Initial Value of the Stage Variable to
"@PARTITIONNUM - @NUMPARTITIONS + 1".
3.Set the derivation of the stage variable to "svCounter + @NUMPARTITIONS".
4.Create a column(counter) in the output of the Transformer and set the derivation of the column(counter) to svCounter(stage variable)
For 4 node configuration each instance will start at a different number, eg. -3, -2,-1,0 When the counter is incremented each instance is increment by the number of partitions, eg. 4. This gives us a sequence in instance 1 of 1, 5, 9, 13... Instance 2 is 2, 6, 10, 14... etc.In this process the counter will always start from 1.This method only works if the input data is evenly balanced i.e. equal number of rows going through each partition.
In 8.5 version developer can generate the unique counter(Surrogate Key) by using Surrogate Key tab in the transformer.User need to mention database sequence name and database crendentials where database sequence name is created.
