Table of Contents

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  1. Preface
  2. Analyst Service
  3. Content Management Service
  4. Data Integration Service
  5. Data Integration Service Architecture
  6. Data Integration Service Management
  7. Data Integration Service Grid
  8. Data Integration Service Applications
  9. Metadata Manager Service
  10. Model Repository Service
  11. PowerCenter Integration Service
  12. PowerCenter Integration Service Architecture
  13. High Availability for the PowerCenter Integration Service
  14. PowerCenter Repository Service
  15. PowerCenter Repository Management
  16. PowerExchange Listener Service
  17. PowerExchange Logger Service
  18. SAP BW Service
  19. Search Service
  20. System Services
  21. Test Data Manager Service
  22. Web Services Hub
  23. Application Service Upgrade
  24. Application Service Databases
  25. Connecting to Databases from Windows
  26. Connecting to Databases from UNIX
  27. Updating the DynamicSections Parameter of a DB2 Database

Blocking Data

Blocking Data

You can include multiple input group transformations in a mapping. The DTM passes data to the input groups concurrently. However, sometimes the transformation logic of a multiple input group transformation requires that the DTM block data on one input group while it waits for a row from a different input group.
Blocking is the suspension of the data flow into an input group of a multiple input group transformation. When the DTM blocks data, it reads data from the source connected to the input group until it fills the reader and transformation buffers. After the DTM fills the buffers, it does not read more source rows until the transformation logic allows the DTM to stop blocking the source. When the DTM stops blocking a source, it processes the data in the buffers and continues to read from the source.
The DTM blocks data at one input group when it needs a specific row from a different input group to perform the transformation logic. After the DTM reads and processes the row it needs, it stops blocking the source.