[teiid-dev] Proposal to further refine the JCA Connectors

[Ramesh Reddy]

After the 7.0 M3 release, and based some initial user feed back and
issues we have seen, we would like to propose change in the how the
Connector are defined.

Traditionally in Teiid <= 6.2 and in Metamatarix

Connector Binding = Translation Layer + Source Connection

With the JCA changes, "Connector Binding" became the JCA Connector.
However, in the container a Source is defined with a "Data Source",
especially for relational sources the equation became

Data Source = Managed Connection = Source Connection

Connector Binding = Translation Layer + Data Source

since the "Data Source" is defined with its own connector (i.e. -ds.xml
file) in the container, to support the "Connector Binding" in container,
we exposed the "Translation Layer" as another JCA Connector. So, now
this became

Connector Binding = JCA Connector + Data Source

But, 

JCA Connector = Managed Conection
Connector Binding = Managed Connection + Managed Connection

Now, this became an issue to have a managed connection over managed
connection. Teiid does not *really* need the "Managed Connection" for
the translation layer, but it *really* needs in the "source connection",
so we want propose splitting the "Connector Binding" into two

Translation Layer --> becomes a non-managed connection (not JCA)
Source Connection --> becomes managed connection (JCA)

This has some pros and cons
Pros
1) Translation layer would be independent of connection layer
2) Since translation layer is independent of the environment changes,
they are portable and can be included in the VDB to migrate from one
environment to another.
3) Since the Connection layer is independent of Translation layer it
becomes more general purpose JCA connector, that can be used with other
applications. With out these changes, this connector was previously only
to be used with Teiid. This also paves easier way to handle any type JCA
connector.

Cons.
1) Only JDBC Connector had two distinct configurations to define the
connector before. Going forward Teiid would need to devide the code in
all the Connectors between the translation layer and connection layer
and package as such. One as the regular jar file and as the JCA
connector.
2) Two separate configuration files to define the layers
3) Dependent jar management for the translation layer.
4)