A new GENERATION column was added for existing Dynamic System Tables (DST) with definitional changes. The GENERATION column includes a conceptual "generation" number. When the table is queried, this column is populated with a 1, representing generation 1. All existing table definitions from Version 14.0 and newly added tables in Version 15.0 are considered generation 0. Therefore, you can use the generation number to know which definition you currently have installed (SQL and DR).
Future post Version 15.0 definitional changes to existing tables will either:
Sysview is allowed to use a new internal protocol to specify which generation definition is used to return data. This method allows Sysview to see new Version 15.0 columns, in a Version 15.0 MUF before installing the new Version 15.0 definitions. This allows for an easy fallback to Version14.0 if needed.
The generation number concept allows you to upgrade the DST definitions independent of release boundaries. It also allows CA Datacom to change DST definitions during a release cycle if needed, without impacting Sysview.
A true SQL query of the DST must always return data which matches the definition in the CXX/DDD. The Version 15.0 code line for the DST recognizes the definition of the base 1000 and constructs the row that it wants. The code recognizes two definitions, the Version 14.0 definition and the Version 15.0 definition.
This allows you to perform the upgrade and still execute with the Version 14.0 definitions with zero outage. However, new tables, new fields, or altered fields are not available in this mode. This is appropriate for the upgrade until there is no risk that you will fall back to Version 14.0. To upgrade definitions to 15.0, when you have a few seconds of time to close all users of the DST base, catalog the Version 15.0 definitions, and then allow a reopen. At which point, the 15.0 definitions are available.
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