[teiid-dev] [teiid-designer-dev] VDB Versioning Feature

[John Verhaeg]

On Feb 8, 2010, at 10:07 AM, Ramesh Reddy wrote:

> In Teiid a VDB is always represented by its name and version. Together
> they both represented a unique name for VDB. Although a version
> represents a particular schema version, 
> 
> 1) It is considered as a entirely different schema then that of the
> original VDB inside the Teiid runtime.
> 2) Usually version numbers are presented in the repository systems with
> implicit rollback behavior. Teiid gives no such rollback functionality.
> 3) Confusion with automatic version upgrade. If a new VDB with same name
> is deployed, then version on this VDB is upgraded to next numerical
> number. The user does not even know what that version number is until
> they use some tool to figure out which version number that VDB is
> deployed under. This creates confusion.
> 4) If there are multiple VDB with different version numbers deployed in
> runtime and client is connecting with no explicit version number, then
> Teiid connects to "latest" or a VDB at "default" level. This again seems
> magical than honoring the explicit behavior.
> 5) Schema version is generally not supported by any RDBMS vendors.
> 6) In MMx product line this meant to represent the metadata repository
> version, but Teiid no longer has this concept. 
> 7) It was a way to move production users from one version of the VDB to
> another with out interruptions. In our opinion, this is more for the
> development environments than prod.


Not sure if I agree with all the "confusion" you feel this causes, but I'm certainly good with removing this capability.  The user can always just give it a different name, right?

Thanks,

JPAV