10:47 a.m.
I want to discuss the proposal to modify the connector api to produce runtime metadata
objects from
source metadata a bit; firstly to confirm my correct understanding and ensure that I'm
understanding the full value.
If I understand the proposal, the connector API would be expanded so the connector can
provide the metadata of the source system via an object representation akin to JDBC
metadata. This would allow a user of Teiid embedded to create bindings to source systems
and query those systems without any model or VDB. Users would be able to submit queries
to Teiid that joined across the source systems much like they would write in a
transformation for a view model. Is all of this correct?
Unless I'm missing some additional utility of this approach, I don't really see
much value in this approach. On the contrary, I think it undermines the value of Teiid by
offering federation without much abstraction. I don't see how this leads to
application code that significantly less brittle than what users would write without us,
and I think it leads users down a dead end. Much of the code they create around this
approach would likely be thrown away were they to adopt full usage of Teiid.
I also think that by doing this now, we are potentially missing an opportunity to improve
our integration story for community members who might want to integrate their products
with Teiid. There has been a longstanding desire to reduce the effort required to create
an importer, and there is also a requirement for alternative tooling. There are a lot of
balls up in the air right now and I think we should take this opportunity to look at the
all of APIs that we are going to expose and rationalize them as much as possible.
My preferred approach would be to answer the big question first. What is our canonical
representation of metadata? Is it DDL, or something else? Once we've done that, then
we should define the APIs and tools to create the metadata, and the hooks to provide it.
~jd
----- "Steven Hawkins" <shawkins(a)redhat.com> wrote:
There are three main engineering goals for the 6.2 release cycle
(~12
weeks):
To provide legacy server features to the embedded deployment, to
provide a simple client/server runtime mode, and to provide metadata
through connectors for a simple query mode.
At a high level our requirements are:
1. Port the Membership, Authentication, Session, and Tracking
(CommandLogging) services for use in embedded. This is
straight-forward except for the authentication service, which will
require treating the only source for authorization information as the
vdb itself in the form of an associated xml file (note that we are not
doing something new here yet, the schema for defining policies was
introduced in 5.5.1). This is covered by TEIID-663 (with subtasks
TEIID-664 - 667) and TEIID-668.
2. Provide a Java main that will launch the "server" with a socket
transport. - Needs a JIRA
3. Ensure adminapi/admin shell coverage of all exposed functionality -
the console should not be necessary for this release. There is not a
a JIRA for this as such, but needs to be addressed as service changes
are made.
4. Modify the connector api to produce runtime metadata objects from
source metadata. This metadata facility will probably have a
superficial resemblance to JDBC DatadataMetadata. The QMI and other
engine logic will need to be modified to support this "modelless"
query mode. - Needs a JIRA
The assumption with all these is that the current server mechanisms
for configuration and clustering are disregarded. We are specifically
not attempting to provide a clustered server that is feature/api
compatible with legacy MetaMatrix. This work should also have minimal
to no impact on Designer's usage of Teiid embedded. Any new work in
designer would be a stretch goal only.
The engineering stretch goals for this release are:
1. Provide JOPR plugins for monitoring and additional adminapi
functionality. Van has initially indicated that he would like for
these to remain out of Teiid proper until they seem usable wrt the
release at some point much later in the cycle.
2. Have definitive plans around Teiid owned metadata in a persistent
form, which has already been on introduced as a topic on the
dev-list.
3. Re-implement file and database based artifact access through JCR
(DNA) - with an eye toward using JCR as a means to provide "cluster"
features, but that would still be api compatible with the embedded
implementation (JCR backed by the filesystem).
4. Refine service loading/wiring/configuration in MC or other
consistent container strategy.
5. Allow for pass-through ddl in both the single source and
multi-source scenarios - TEIID-669
In this bucket as well is a task to provide a doc set around our
legacy SOAP services and some proposed REST services in terms of how
they can be implemented with JBoss projects with a loose coupling to
Teiid. This will be covered under its own JIRA with multiple subtasks
covering prospective services use cases.
A 6.3 bucket has been created out of pushed 6.2 items and select
issues in 6.x. This will serve as the place holder for the further
refinement of the new simplified server approach At the end of 6.3 we
should have re-established our clustering story, a good story around
configuration changes, fully incorporated JOPR, and carried-forward
any lingering server features.
On the non-engineering side of things we have the requirements of:
1. Updating the server extension guide to cover things from an
embedded/simplified perspective given the changes to command logging,
membership domains, etc.
2. Update the connector developers guide - TEIID-104
3. Add the jdbc developers guide - TEIID-315
There are stretch goals of:
1. Adding additional screen casts covering a broader set of common
uses.
2. Add more examples to the kit, especially highlighting use of
non-relational sources.
3. Get Teiid as a recognized source in other products/projects -
squirrel, dtp, hibernate, etc.
Note there are missing JIRAs for a lot of these items and the priority
may not yet be assigned correctly for items identified as
requirements. Devs and leads should feel free to help fill in gaps.
Let me know if there is anything that has been left out or what we
should dive into a little more detail on.
Steve
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