3:37 p.m.
I want to outline a strategy for using the Teiid server to manage the Designer's
Eclipse workspace source bindings (model to connector mappings). These source bindings are
used when a user previews data in the Designer. Some of us have talked about this in the
past but I wanted to get it out there for all to see and comment on. Let me know what you
think.
Here's the strategy:
For each Teiid server registered within the Designer, an associated VDB will be created.
These VDBs will be hidden from the user and will not appear in their Eclipse workspace.
These VDBs will be deployed (unbeknownst to the user) to their associated Teiid server and
will contain all the models from the workspace that have source bindings with connectors
installed on that server. These local, hidden VDBs and their associated deployed VDB must
stay in sync. The class in charge of this will be the SourceBindingsManager (SBM).
Here are some use cases:
Designer Startup Use Case - same as Server Refresh Use Case. When the Designer is started
each server found in the persisted server registry is refreshed.
Server Refresh Use Case- when a Teiid server is refreshed within Designer, the SBM for
that server will also be refreshed. The SBM's cache of SourceBindings is cleared and
re-populated based on information gathered after obtaining the deployed, hidden VDB from
each server.
- delete all existing hidden, local VDBs
- for each registered Teiid server:
-- create a hidden, local VDB
-- if the hidden VDB is *not* deployed on the server no action is taken by the SBM
-- if the hidden VDB is deployed on the server the SBM will:
--- for each model in the deployed VDB:
---- if model does *not* exist in workspace remove model from deployed VDB unless path
equals a closed project path
---- if model does exist in workspace:
----- if model does *not* have a connector remove it from deployed VDB (see Issues
below)
----- if model does have one or more connectors add model to local VDB and create a
SourceBinding with the connectors
--- if deployed VDB has no models delete it from server (see Issues below)
Design Time Use Cases (hidden VDB already exists)
A source binding is created:
- ensure model exists in hidden VDB
- if model already has a SourceBinding remove from hidden VDB
- add SourceBinding to hidden VDB
- using Admin API add connector to model of deployed VDB (or redeploy entire VDB, see
Issues below)
A source binding is removed:
- if the model does *not* exist in the VDB throw Exception (not sure this will happen,
maybe an assertion)
- remove model from hidden VDB
- remove model from deployed VDB (or redeploy entire VDB, see Issues below)
A project is opened:
- follow Server Refresh instructions for each model in the project
A project is closed:
- for each model in project, follow remove source binding instructions except don't
do anything to deployed VDB. These connectors need to stay in the deployed VDB for when
the project is opened.
A project is deleted:
- for each model in project follow instructions for removing a source binding except only
redeploy done removing all models
A model is deleted:
-- if a source binding exists on this server then follow instructions for removing a
source binding
Designer Shutdown Use Case
- SBM has nothing to do
Issues
- Can we have a deployed VDB on Teiid that doesn't have any models (maybe marked
inactive)? If yes, we can create the VDB when we create the associated Teiid server
object. Then the deployed VDB lifecycle would be the same as the Designer's Teiid
server object. Trick would be to make sure this deployed VDB exists the first time the
connection is established. Remember servers can be created without connecting to them.
- Can you query a model with a connector that is in a VDB that has another model which
doesn't have a connector? If yes, we can add/remove models to the hidden VDB as models
are created/removed in the workspace.
- It would be much simpler for us to manage the local VDB and redeploy it in its entirety
each time a change is made but their might be performance issues associated with that. But
this might be the only way to get the indexes updated.