Expand stage: Partitioning on input Links (DataStage)
The Partitioning section allows you to specify details about how the incoming data is partitioned or collected before the expansion is performed.
By default the stage uses the Same partitioning method and this cannot be altered. This preserves the partitioning already in place.
If the Expand stage is set to execute in sequential mode, but the preceding stage is executing in parallel, then you can set a collection method from the Collector type drop-down list. This will override the default auto collection method.
The following Collection methods are available:
- (Auto). This is the default collection method for the Expand stage. Normally, when you are using Auto mode, IBM® DataStage® will eagerly read any row from any input partition as it becomes available.
- Ordered. Reads all records from the first partition, then all records from the second partition, and so on.
- Round Robin. Reads a record from the first input partition, then from the second partition, and so on. After reaching the last partition, the operator starts over.
- Sort Merge. Reads records in an order based on one or more columns of the record. This requires you to select a collecting key column from the Available list.
The Partitioning section normally allows you to specify that data arriving on the input link should be sorted before the expansion is performed. This facility is not available on the expand stage.