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  1. Preface
  2. Mappings
  3. Mapplets
  4. Mapping Parameters
  5. Where to Assign Parameters
  6. Mapping Outputs
  7. Generate a Mapping from an SQL Query
  8. Dynamic Mappings
  9. How to Develop and Run a Dynamic Mapping
  10. Dynamic Mapping Use Cases
  11. Mapping Administration
  12. Export to PowerCenter
  13. Import From PowerCenter
  14. Performance Tuning
  15. Pushdown Optimization
  16. Partitioned Mappings
  17. Developer Tool Naming Conventions

Developer Mapping Guide

Developer Mapping Guide

Maintain Order in a Partitioned Mapping

Maintain Order in a Partitioned Mapping

You can establish order in a mapping with a sorted flat file source, a sorted relational source, or a Sorter transformation. When the Data Integration Service adds a partition point to a mapping, it might redistribute data and lose an order established earlier in the mapping. To maintain order in a partitioned mapping, you must specify that some transformations and Write transformations maintain the row order.
You can specify that the following mapping objects maintain the row order of the input data:
  • Expression transformation
  • Java transformation
  • Sequence Generator transformation
  • SQL transformation
  • Write transformation
For example, if a relational target has a database trigger that depends on the data being written in the sorted order, configure the Write transformation to maintain the row order.
When you configure Write transformations to maintain row order, the Data Integration Service uses a single thread to write to the target. If an Aggregator transformation that uses sorted input precedes the Write transformation, the Data Integration Service uses a single thread to process both the Aggregator transformation and the target.
When you configure all other transformations to maintain row order, the Data Integration Service determines the optimal number of threads for the transformation pipeline stage while maintaining the order.
The method that you use to configure transformations to maintain row order depends on the following object types:
Expression, Sequence Generator, or SQL transformation
Select the
Maintain Row Order
property in the
Advanced
properties of an Expression, Sequence Generator, or SQL transformation.
Java transformation
Select the
Stateless
property in the
Advanced
properties of a Java transformation.
Write transformation
Select the
Maintain Row Order
property in the
Advanced
properties of the Write transformation.

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