Head
stage
The Head Stage is a
Development/Debug stage. It can have a single input link and a single output
link.
It is one of a number
of stages that InfoSphere DataStage provides to help you sample data
The Head Stage selects
the first N rows from each partition of an input data set and copies the
selected
rows to an output data
set. You determine which rows are copied by setting properties which allow you
to specify:
·
The number of rows to copy
·
The partition from which the rows are copied
·
The location of the rows to copy
·
The number of rows to skip before the copying
operation begins
This stage is helpful
in testing and debugging applications with large data sets. For example, the
Partition
property lets you see
data from a single partition to determine if the data is being partitioned as
you
want it to be. The Skip
property lets you access a certain portion of a data set.
