Write Range Map stage: Partitioning tab

The Partitioning tab normally allows you to specify details about how the incoming data is partitioned or collected before it is written to the file or files. In the case of the Write Range Map stage execution is always sequential, so there is never a need to set a partitioning method.

You can set a collection method if collection is required. The following Collection methods are available:

(Auto). This is the default collection method for the Write Range Map stage. Normally, when you are using Auto mode, InfoSphere® 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 operation 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 tab also allows you to specify that data arriving on the input link should be sorted before the write range map operation is performed. If the stage is collecting data, the sort occurs before the collection. The availability of sorting depends on the collecting method chosen (it is not available for the default auto methods).

Select the check boxes as follows:

Perform Sort. Select this to specify that data coming in on the link should be sorted. Select the column or columns to sort on from the Available list.
Stable. Select this if you want to preserve previously sorted data sets. This is the default.
Unique. Select this to specify that, if multiple records have identical sorting key values, only one record is retained. If stable sort is also set, the first record is retained.

If NLS is enabled an additional button opens a dialog box allowing you to select a locale specifying the collate convention for the sort.

You can also specify sort direction, case sensitivity, whether sorted as ASCII or EBCDIC, and whether null columns will appear first or last for each column. Where you are using a keyed partitioning method, you can also specify whether the column is used as a key for sorting, for partitioning, or for both. Select the column in the Selected list and right-click to invoke the shortcut menu. Because the partition mode is set and cannot be overridden, you cannot use the stage sort facilities, so these are disabled.