Handling Large Diagrams
As you may imagine, data flow diagrams can become quite large. If you trace starting at some commonly used fact or dimension in the warehouse, and it has thousands of columns, it is auite likely that it would produce a diagram with tens or hundreds of thousands of objects and an equally large number of links or lines. The Diagram presentation is designed to handle exceptionally large diagrams. In fact, much larger than could be considered reasonable and useful, as tens of thousands of objects and links really defy effective analysis, let alone understanding.
The Classic Diagram presentation is an older methodology, and is not optimized for larger diagrams like the Diagram presentation, and thus the Classic Diagram should only be used for smaller.
Each time you view an object and go to the Lineage tab the lineage options that are NOT remembered as a part of User Preferences are reset to their default settings. See table.
Each time you bookmark a URL for an object while viewing the Lineage tab only those lineage options are remembered with the URL. See table.
-However, for URLs, the Direction is remembered.
Option | Default | Remembered in User Preferences | Remembered in URL (Bookmark) |
Type | DATA FLOW | Yes | |
Direction | ANY | Yes | Yes |
Control Flow | NONE | Yes | |
Columns | NO | ||
Depth | FULL | Yes | Yes |
Filters | NONE | Yes | |
Display As | DIAGRAM | Yes | Yes |
Example
When working with potentially large diagrams, you will note there are two phases in presentation process:
- Retrieving (or Loading) the lineage graph from the database
- Drawing the lineage diagram