Table of Contents

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  1. Preface
  2. Understanding Pipeline Partitioning
  3. Partition Points
  4. Partition Types
  5. Pushdown Optimization
  6. Pushdown Optimization Transformations
  7. Real-time Processing
  8. Commit Points
  9. Row Error Logging
  10. Workflow Recovery
  11. Stopping and Aborting
  12. Concurrent Workflows
  13. Grid Processing
  14. Load Balancer
  15. Workflow Variables
  16. Parameters and Variables in Sessions
  17. Parameter Files
  18. FastExport
  19. External Loading
  20. FTP
  21. Session Caches
  22. Incremental Aggregation
  23. Session Log Interface
  24. Understanding Buffer Memory
  25. High Precision Data
  26. POWERCENTERHELP

Advanced Workflow Guide

Advanced Workflow Guide

Hash User Keys Partition Type

Hash User Keys Partition Type

In hash user keys partitioning, the Integration Service uses a hash function to group rows of data among partitions based on a user-defined partition key. You choose the ports that define the partition key:
This mapping includes a flat file source, a series of transformations including a Sorter transformation, and an Oracle target.
When you specify hash auto-keys partitioning in the preceding mapping, the Sorter transformation receives rows of data grouped by the sort key, such as ITEM_DESC. If the item description is long, and you know that each item has a unique ID number, you can specify hash user keys partitioning at the Sorter transformation and select ITEM_ID as the hash key. This might improve the performance of the session since the hash function usually processes numerical data more quickly than string data.
If you select hash user keys partitioning at any partition point, you must specify a hash key. The Integration Service uses the hash key to distribute rows to the appropriate partition according to group.
For example, if you specify key range partitioning at a Source Qualifier transformation, the Integration Service uses the key and ranges to create the WHERE clause when it selects data from the source. Therefore, you can have the Integration Service pass all rows that contain customer IDs less than 135000 to one partition and all rows that contain customer IDs greater than or equal to 135000 to another partition.
If you specify hash user keys partitioning at a transformation, the Integration Service uses the key to group data based on the ports you select as the key. For example, if you specify ITEM_DESC as the hash key, the Integration Service distributes data so that all rows that contain items with the same description go to the same partition.
To specify the hash key, select the partition point on the Partitions view of the Mapping tab, and click Edit Keys. This displays the Edit Partition Key dialog box. The Available Ports list displays the connected input and input/output ports in the transformation. To specify the hash key, select one or more ports from this list, and then click Add.
To rearrange the order of the ports that define the key, select a port in the Selected Ports list and click the up or down arrow.


Updated July 04, 2018