Head stage: Stage tab (DataStage)

The Stage tab enables you to control aspects of the Head stage.

Double-click the stage to open the stage properties panel. The Properties section on the Stage tab lets you specify what the stage does. The Advanced section allows you to specify how the stage executes. The Stage tab has the following properties:

Table 1. Properties
Category/Property	Values	Default	Mandatory?	Repeats?	Dependent of
Rows/All rows	True/False	False	N	N	N/A
Rows/Number of rows (per partition)	Count	10	N	N	N/A
Rows/Period (per partition)	Number	N/A	N	N	N/A
Rows/Skip (per partition)	Number	N/A	N	N	N/A
Partitions/All partitions	Partition Number	N/A	N	Y	N/A

All rows

Copy all input rows to the output data set. You can skip rows before Head performs its copy operation by using the Skip property. The Number of Rows property is not needed if All Rows is true.

Number of rows (per partition)

Specify the number of rows to copy from each partition of the input data set to the output data set. The default value is 10. The Number of Rows property is not needed if All Rows is true.

Period (per partition)

Copy every Pth record in a partition, where P is the period. You can start the copy operation after records have been skipped by using the Skip property. P must equal or be greater than 1.

Skip (per Partition)

Ignore the first number of rows of each partition of the input data set, where number is the number of rows to skip. The default skip count is 0.

All partitions

If False, copy records only from the indicated partition, specified by number. By default, the operator copies rows from all partitions.

Advanced

This section allows you to specify the following:

Execution Mode. The stage can execute in parallel mode or sequential mode. In parallel mode the input data is processed by the available nodes as specified in the Configuration file, and by any node constraints specified on the Advanced section. In Sequential mode the entire data set is processed by the conductor node.
Combinability mode. This is Auto by default, which allows IBM® DataStage® to combine the operators that underlie parallel stages so that they run in the same process if it is sensible for this type of stage.
Preserve partitioning. This is Set by default. You can explicitly select Set or Clear. Select Set to request the next stage should attempt to maintain the partitioning.