Hi

As already said, I still think Quarkus/Agroal stays the default and
single supported pool. I think adding a narrow, JVM-only, documented
runtime driver escape hatch is right.

Concretely, I would:
1. Split the PR: runtime driver loading is a small, defensible
feature. The second pool, and per-realm routing are not imho, and
should not ride in on its coattails.
2. I think per-realm routing is a way bigger architectural decision.
3. I think we should have an explicit agreement on the contract before merging.

The best would be to use Agroal, supporting a runtime-mounted driver
in JVM mode. I will ping my Quarkus contacts to get the status of
that.

Regards
JB



On Fri, Jul 24, 2026 at 10:24 PM Yufei Gu <[email protected]> wrote:
>
> Robert,
>
> I don't think these are hypothetical use cases. They've been recurring
> design topics in Polaris for well over a year.
>
>    - A JDBC driver supplied at runtime instead of being on the build time
>    classpath is important for proprietary and Apache license incompatible
>    drivers, such as MySQL. This has been discussed in the community for some
>    time, and PR #4281[4] was blocked by this limitation.
>    - We've also discussed realm based datasource routing repeatedly. For
>    example:
>       - Issue #3890 [1] tracks multi datasource support and explicitly
>       discusses whether separation should be per realm or by workload.
>       - PR #1482 [2] proposed a concrete realm to datasource mapping. The
>       discussion wasn't that the use case was invalid, but that Quarkus's 
> build
>       time datasource model made it difficult.
>       - PR #3960 [3] introduced DataSourceResolver as groundwork for
>       datasource routing. The feedback was to refine the design, not
> that the use
>       case itself shouldn't be supported.
>
> Given this history, I don't think the question is whether these are real
> use cases. The project has already acknowledged them multiple times.
>
> Romain, thanks for the suggestion. I wish this could be resolved upstream
> in Quarkus, but I don't have much hope, since build time dependency
> resolution is one of Quarkus's core design principles.
>
> [1] https://github.com/apache/polaris/issues/3890
>
> [2] https://github.com/apache/polaris/pull/1482
>
> [3] https://github.com/apache/polaris/pull/3960
>
> [4] https://github.com/apache/polaris/pull/4281
>
> Yufei
>
>
> On Fri, Jul 24, 2026 at 8:54 AM Romain Manni-Bucau <[email protected]>
> wrote:
>
> > If down stream users need to build anything instead of mount the driver
> > then polaris becomes a lib and not a server, think very few consumer see it
> > this way nor would like it so I would favor runtime support.
> >
> > The side note is that it is always better to not compète with its own stack
> > so maybe two push back to quarkus natively before acting there.
> >
> >
> > Romain Manni-Bucau
> > @rmannibucau <https://x.com/rmannibucau> | .NET Blog
> > <https://dotnetbirdie.github.io/> | Blog <https://rmannibucau.github.io/>
> > | Old
> > Blog <http://rmannibucau.wordpress.com> | Github
> > <https://github.com/rmannibucau> | LinkedIn
> > <https://www.linkedin.com/in/rmannibucau> | Book
> > <
> > https://www.packtpub.com/en-us/product/java-ee-8-high-performance-9781788473064
> > >
> > Javaccino founder (Java/.NET service - contact via linkedin)
> >
> > Le ven. 24 juil. 2026, 17:50, Robert Stupp <[email protected]> a écrit :
> >
> > > Hi Yufei,
> > >
> > > Option 1 would not provide either capability at runtime in the upstream
> > > Polaris distribution.
> > > Optional drivers would be added through a downstream build or assembly,
> > and
> > > datasource creation would remain Quarkus-managed.
> > >
> > > That is intentional rather than a missing part of option 1.
> > > I mentioned runtime driver loading and per-realm routing because they are
> > > the two use cases stated for the POC, not because I think the project has
> > > already agreed that Polaris itself must support both.
> > >
> > > The concrete current ask I see is a viable path for optional drivers that
> > > Polaris cannot distribute in ASF releases.
> > > Runtime loading is one possible answer to that ask.
> > > A downstream build or assembly is another.
> > >
> > > Dynamic per-realm datasource creation is a separate future design.
> > > I do not think it should become an implicit requirement for the
> > > optional-driver decision before its isolation, lifecycle, resource, and
> > > operational contract has been discussed.
> > >
> > > So before evaluating option 1 against option 2's capabilities, I think we
> > > need to decide whether runtime driver loading and Polaris-owned dynamic
> > > datasource creation are project requirements.
> > > If both are requirements, option 1 is naturally excluded.
> > > If they are not, the POC's additional capabilities should not by
> > themselves
> > > become acceptance criteria for every alternative.
> > >
> > > My preference remains to preserve the Quarkus-managed path and address
> > the
> > > optional-driver ask as narrowly as possible.
> > >
> > > Cheers,
> > > Robert
> > >
> > > On Thu, Jul 23, 2026 at 8:59 PM Yufei Gu <[email protected]> wrote:
> > >
> > > > >
> > > > > That ask does not by itself justify moving all supported deployments
> > > away
> > > > > from Quarkus datasource management.
> > > > > Doing so would make Polaris responsible for configuration
> > > compatibility,
> > > > > lifecycle, health, metrics, tracing, credentials-provider
> > integration,
> > > > > shutdown, upgrades, and the support matrix currently covered by
> > > Quarkus.
> > > >
> > > >
> > > > > 1. Keep Quarkus-managed data-sources and document the downstream
> > > > >    build/assembly path for optional drivers.
> > > > > 2. Keep Quarkus-managed data-sources as the default and add a
> > > > deliberately
> > > > >    limited JVM-only runtime-driver escape hatch.
> > > > > 3. Replace Quarkus-managed data-sources completely.
> > > >
> > > >
> > > > My current preference is ... (option1).
> > > >
> > > >
> > > > Robert, one thing I'm still unclear about is how option 1 would support
> > > the
> > > > following use cases that you mentioned:
> > > >
> > > >    - Loading optional JDBC drivers at runtime.
> > > >    - Creating datasources dynamically as a building block for future
> > per
> > > >    realm routing.
> > > >
> > > > My PR proposes option 2 because it addresses these use cases while
> > > keeping
> > > > the existing Quarkus managed deployment path unchanged.
> > > >
> > > > Yufei
> > > >
> > > >
> > > > On Thu, Jul 23, 2026 at 8:59 AM Dmitri Bourlatchkov <[email protected]>
> > > > wrote:
> > > >
> > > > > Hi Yufei,
> > > > >
> > > > > I wonder why you chose Hikari initially in your PR 4984.
> > Understanding
> > > > that
> > > > > rationale could be helpful for this discussion.
> > > > >
> > > > > Thanks,
> > > > > Dmitri.
> > > > >
> > > > > On Wed, Jul 22, 2026 at 11:28 PM Yufei Gu <[email protected]>
> > > wrote:
> > > > >
> > > > > > Looks like we have two options at this point: Hikari (Alex, me) and
> > > > > Agroal
> > > > > > (Dmitri, JB, Romain).
> > > > > >
> > > > > > Is there any further investigation we should do before making a
> > > > decision?
> > > > > > Or are we ready to start a vote?
> > > > > >
> > > > > > Yufei
> > > > > >
> > > > > >
> > > > > > On Thu, Jul 16, 2026 at 10:15 PM Romain Manni-Bucau <
> > > > > [email protected]
> > > > > > >
> > > > > > wrote:
> > > > > >
> > > > > > > Maybe add "is there more than one committer" on the project as a
> > > > > > criteria.
> > > > > > > Agroal is far to be my preferred pool but it is as easy as others
> > > in
> > > > > > terms
> > > > > > > of config starting from properties ([1]) and using its listeners.
> > > > > > > Also note that I assume all properties will not be exposed but
> > > > > abstracted
> > > > > > > by polaris configuration (potentially enabling a switch later or
> > a
> > > > > > > multipool support like in Apache TomEE) so maybe it is the first
> > > > thing
> > > > > to
> > > > > > > define, the needed properties and callbacks?
> > > > > > >
> > > > > > > [1]
> > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> > https://github.com/agroal/agroal/blob/517fd36ab0cf1faebaae7d57a55c788d499a4c88/agroal-api/src/main/java/io/agroal/api/configuration/supplier/AgroalPropertiesReader.java#L56
> > > > > > >
> > > > > > > Romain Manni-Bucau
> > > > > > > @rmannibucau <https://x.com/rmannibucau> | .NET Blog
> > > > > > > <https://dotnetbirdie.github.io/> | Blog <
> > > > > https://rmannibucau.github.io/
> > > > > > >
> > > > > > > | Old
> > > > > > > Blog <http://rmannibucau.wordpress.com> | Github
> > > > > > > <https://github.com/rmannibucau> | LinkedIn
> > > > > > > <https://www.linkedin.com/in/rmannibucau> | Book
> > > > > > > <
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> > https://www.packtpub.com/en-us/product/java-ee-8-high-performance-9781788473064
> > > > > > > >
> > > > > > > Javaccino founder (Java/.NET service - contact via linkedin)
> > > > > > >
> > > > > > >
> > > > > > > Le jeu. 16 juil. 2026 à 22:18, Alexandre Dutra <
> > [email protected]>
> > > a
> > > > > > > écrit :
> > > > > > >
> > > > > > > > Hi all,
> > > > > > > >
> > > > > > > > I don't think the actual pool implementation matters much, but
> > I
> > > > > would
> > > > > > > > weigh in some important criteria before choosing:
> > > > > > > >
> > > > > > > > - Is it easily configurable?
> > > > > > > > - Is it easily instrumentable?
> > > > > > > > - Is it well documented & maintained?
> > > > > > > >
> > > > > > > > While Agroal is the de facto choice for Quarkus (it's a JBoss
> > > > lib), I
> > > > > > > > am not sure it outperforms Hikari for all the criteria above.
> > > > > > > >
> > > > > > > > Thanks,
> > > > > > > > Alex
> > > > > > > >
> > > > > > > > On Thu, Jul 16, 2026 at 6:22 PM Yufei Gu <[email protected]
> > >
> > > > > wrote:
> > > > > > > > >
> > > > > > > > > Thanks everyone for chiming in. Agroal is a good option as
> > > well.
> > > > It
> > > > > > > looks
> > > > > > > > > like we're reaching consensus on direct datasource management
> > > at
> > > > > > > runtime.
> > > > > > > > > I'll start working on the implementation soon.
> > > > > > > > >
> > > > > > > > > Yufei
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > On Thu, Jul 16, 2026 at 4:16 AM Jean-Baptiste Onofré <
> > > > > > [email protected]>
> > > > > > > > > wrote:
> > > > > > > > >
> > > > > > > > > > Hi all,
> > > > > > > > > >
> > > > > > > > > > I agree that direct datasource management at runtime is a
> > > > better
> > > > > > > > > > approach than relying on quarkus-datasource, which
> > currently
> > > > > > requires
> > > > > > > > > > build-time dependencies.
> > > > > > > > > >
> > > > > > > > > > However, we can stay within the Quarkus ecosystem and avoid
> > > > > > > > > > introducing new dependencies by using Agroal, which is
> > > already
> > > > > > > > > > included in our dependencies. This also keeps the door open
> > > to
> > > > > > > > > > combining it with Panache in the future, should we decide
> > to
> > > do
> > > > > so.
> > > > > > > > > >
> > > > > > > > > > Regards,
> > > > > > > > > > JB
> > > > > > > > > >
> > > > > > > > > > On Thu, Jul 16, 2026 at 1:28 AM Yufei Gu <
> > > [email protected]
> > > > >
> > > > > > > wrote:
> > > > > > > > > > >
> > > > > > > > > > > > If our goal is to transition entirely to a
> > > "runtime-driven"
> > > > > > > > > > architecture,
> > > > > > > > > > > we should commit to it completely by fully removing the
> > > > > > > > > > > io.quarkus:quarkus-datasource
> > > > > > > > > > > dependency and switching to Hikari unconditionally.
> > > > > > > > > > >
> > > > > > > > > > > Good point, Alex! I'm open to that. If the community
> > > agrees,
> > > > I
> > > > > > can
> > > > > > > > make
> > > > > > > > > > > that change.
> > > > > > > > > > >
> > > > > > > > > > > Romain, I chose Hikari because it is lean, fast, simple.
> > > I'm
> > > > > open
> > > > > > > to
> > > > > > > > > > > alternatives like dbcp2 if its evaluation proves better.
> > As
> > > > you
> > > > > > > said,
> > > > > > > > > > both
> > > > > > > > > > > have pros and cons.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > Yufei
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > On Wed, Jul 15, 2026 at 11:03 AM Romain Manni-Bucau <
> > > > > > > > > > [email protected]>
> > > > > > > > > > > wrote:
> > > > > > > > > > >
> > > > > > > > > > > > Dumb question: why hikari? it has some issues like not
> > > > > > respecting
> > > > > > > > its
> > > > > > > > > > conf
> > > > > > > > > > > > intentionally (max size in particular is the one which
> > > > hurts
> > > > > > > since
> > > > > > > > you
> > > > > > > > > > > > overconsume for a moment your database connections ==
> > > > prevent
> > > > > > > some
> > > > > > > > > > services
> > > > > > > > > > > > to connect when scaled and tuned at max count), there
> > is
> > > no
> > > > > > > silver
> > > > > > > > > > bullet
> > > > > > > > > > > > but something like dbcp2 can be neat to start _there_
> > if
> > > > > agroal
> > > > > > > is
> > > > > > > > not
> > > > > > > > > > used
> > > > > > > > > > > > as a base no - that said I dont see why switching at
> > all,
> > > > > > agroal
> > > > > > > > can be
> > > > > > > > > > > > used without build time integration and stay consistent
> > > > with
> > > > > it
> > > > > > > if
> > > > > > > > a
> > > > > > > > > > day it
> > > > > > > > > > > > comes back?
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > Romain Manni-Bucau
> > > > > > > > > > > > @rmannibucau <https://x.com/rmannibucau> | .NET Blog
> > > > > > > > > > > > <https://dotnetbirdie.github.io/> | Blog <
> > > > > > > > > > https://rmannibucau.github.io/>
> > > > > > > > > > > > | Old
> > > > > > > > > > > > Blog <http://rmannibucau.wordpress.com> | Github
> > > > > > > > > > > > <https://github.com/rmannibucau> | LinkedIn
> > > > > > > > > > > > <https://www.linkedin.com/in/rmannibucau> | Book
> > > > > > > > > > > > <
> > > > > > > > > > > >
> > > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> > https://www.packtpub.com/en-us/product/java-ee-8-high-performance-9781788473064
> > > > > > > > > > > > >
> > > > > > > > > > > > Javaccino founder (Java/.NET service - contact via
> > > > linkedin)
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > Le mer. 15 juil. 2026 à 19:13, Alexandre Dutra <
> > > > > > > [email protected]>
> > > > > > > > a
> > > > > > > > > > > > écrit :
> > > > > > > > > > > >
> > > > > > > > > > > > > Hi all,
> > > > > > > > > > > > >
> > > > > > > > > > > > > > If jdbc-url is set, Polaris creates and owns the
> > > Hikari
> > > > > > > > > > datasource. If
> > > > > > > > > > > > > it is not set, we keep using the existing Quarkus
> > > > > datasource
> > > > > > > > path.
> > > > > > > > > > > > >
> > > > > > > > > > > > > I have strong reservations regarding this design.
> > > > > > > > > > > > >
> > > > > > > > > > > > > Alternating between a Hikari pool and an Agroal pool
> > > > > > depending
> > > > > > > > on the
> > > > > > > > > > > > > configuration introduces unnecessary complexity and
> > > > > potential
> > > > > > > > > > > > > confusion. A major drawback is that bugs, performance
> > > > > > > > > > characteristics,
> > > > > > > > > > > > > and configuration issues will vary across deployments
> > > > > purely
> > > > > > > > based on
> > > > > > > > > > > > > the underlying connection pool in use.
> > > > > > > > > > > > >
> > > > > > > > > > > > > If our goal is to transition entirely to a
> > > > "runtime-driven"
> > > > > > > > > > > > > architecture, we should commit to it completely by
> > > fully
> > > > > > > > removing the
> > > > > > > > > > > > > io.quarkus:quarkus-datasource dependency and
> > switching
> > > to
> > > > > > > Hikari
> > > > > > > > > > > > > unconditionally.
> > > > > > > > > > > > >
> > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > Alex
> > > > > > > > > > > > >
> > > > > > > > > > > > > On Tue, Jul 7, 2026 at 7:10 PM Yufei Gu <
> > > > > > [email protected]>
> > > > > > > > > > wrote:
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Hi Robert, JB, Dmitri,
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Thanks, this feedback makes sense.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > There are really two motivations here: runtime
> > > loading
> > > > of
> > > > > > > JDBC
> > > > > > > > > > drivers,
> > > > > > > > > > > > > and
> > > > > > > > > > > > > > dynamic datasource creation. The former is useful
> > for
> > > > ASF
> > > > > > > > binaries
> > > > > > > > > > > > where
> > > > > > > > > > > > > a
> > > > > > > > > > > > > > driver is supplied after Polaris is built. The
> > latter
> > > > is
> > > > > a
> > > > > > > > building
> > > > > > > > > > > > block
> > > > > > > > > > > > > > for future per realm datasources.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > I'm OK that Quarkus/Agroal remains the default for
> > > > > > supported
> > > > > > > > > > backends.
> > > > > > > > > > > > > > That's already part of the POC.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > The gap I'm trying to address is where those
> > > > assumptions
> > > > > no
> > > > > > > > longer
> > > > > > > > > > > > hold.
> > > > > > > > > > > > > > Quarkus can select from predefined datasources, but
> > > > they
> > > > > > > still
> > > > > > > > > > need to
> > > > > > > > > > > > be
> > > > > > > > > > > > > > configured ahead of time. It doesn't currently
> > > provide
> > > > > > > Polaris
> > > > > > > > > > with a
> > > > > > > > > > > > > clean
> > > > > > > > > > > > > > way to create new datasources dynamically.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > So my intent is for the contract to be:
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >    - Quarkus/Agroal remains the default.
> > > > > > > > > > > > > >    - Polaris managed JDBC is a JVM only escape
> > hatch
> > > > for
> > > > > > > > runtime
> > > > > > > > > > > > provided
> > > > > > > > > > > > > >    drivers and dynamically created datasources.
> > > > > > > > > > > > > >    - Polaris owns the pool and driver lifecycle on
> > > that
> > > > > > path.
> > > > > > > > > > > > > >    - Per realm datasource routing should be a
> > > separate
> > > > > > design
> > > > > > > > > > > > discussion.
> > > > > > > > > > > > > >    It's out of scope for this POC.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > JB, I agree we should continue using Quarkus JDBC
> > > > drivers
> > > > > > for
> > > > > > > > the
> > > > > > > > > > > > > backends
> > > > > > > > > > > > > > we support directly. This path is mainly for the
> > > cases
> > > > > > > outside
> > > > > > > > that
> > > > > > > > > > > > > model.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Yufei
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > On Tue, Jul 7, 2026 at 8:03 AM Jean-Baptiste
> > Onofré <
> > > > > > > > > > [email protected]>
> > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Hi
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Regarding JDBC drivers in the Quarkus ecosystem
> > (in
> > > > > > > > > > > > quarkus-extensions
> > > > > > > > > > > > > or
> > > > > > > > > > > > > > > quarkiverse), I think we can just leverage the
> > > > quarkus
> > > > > > JDBC
> > > > > > > > > > drivers.
> > > > > > > > > > > > > > > Using another loading mechanism could be
> > > problematic
> > > > > for
> > > > > > > > future
> > > > > > > > > > > > > features
> > > > > > > > > > > > > > > (imagine with we want to try native app buld).
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > What is the problem with using the Quarkus JDBC
> > > > > drivers?
> > > > > > > > > > > > > > > I remember that we agreed to be opinionated about
> > > the
> > > > > > JDBC
> > > > > > > > > > backends
> > > > > > > > > > > > we
> > > > > > > > > > > > > want
> > > > > > > > > > > > > > > to support, so we can be opinionated about the
> > JDBC
> > > > > > drivers
> > > > > > > > :)
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > I'm not against it, but I would like to
> > understand
> > > > > better
> > > > > > > the
> > > > > > > > > > > > > rationale.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Regards
> > > > > > > > > > > > > > > JB
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > On Tue, Jul 7, 2026 at 3:03 PM Robert Stupp <
> > > > > > > [email protected]>
> > > > > > > > > > wrote:
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Thanks for pushing this forward.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > I agree that runtime-provided JDBC drivers are
> > a
> > > > real
> > > > > > > > problem
> > > > > > > > > > to
> > > > > > > > > > > > > solve.
> > > > > > > > > > > > > > > > For ASF-distributed binaries, there are valid
> > > cases
> > > > > > where
> > > > > > > > > > Polaris
> > > > > > > > > > > > > should
> > > > > > > > > > > > > > > > not bundle a driver, but operators still need a
> > > way
> > > > > to
> > > > > > > > provide
> > > > > > > > > > one.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > My concern is that this PR does more than load
> > > > > runtime
> > > > > > > > driver
> > > > > > > > > > jars.
> > > > > > > > > > > > > > > > It also introduces a second datasource stack:
> > > > > > > > Quarkus/Agroal
> > > > > > > > > > via
> > > > > > > > > > > > > > > > `quarkus.datasource.*` on one side, and
> > > > Polaris-owned
> > > > > > > > Hikari
> > > > > > > > > > pools
> > > > > > > > > > > > > via
> > > > > > > > > > > > > > > > `polaris.persistence.relational.jdbc.*` on the
> > > > other.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Those two paths look similar to operators, but
> > > they
> > > > > do
> > > > > > > not
> > > > > > > > > > have the
> > > > > > > > > > > > > same
> > > > > > > > > > > > > > > > contract.
> > > > > > > > > > > > > > > > The Quarkus path brings Quarkus/Agroal
> > lifecycle,
> > > > > > health,
> > > > > > > > > > metrics,
> > > > > > > > > > > > > > > > credentials/secret-manager integrations, and
> > the
> > > > > > broader
> > > > > > > > > > datasource
> > > > > > > > > > > > > > > config
> > > > > > > > > > > > > > > > surface; those are all important for operators.
> > > > > > > > > > > > > > > > The Polaris-managed path means Polaris owns
> > pool
> > > > > > > lifecycle,
> > > > > > > > > > driver
> > > > > > > > > > > > > > > loading,
> > > > > > > > > > > > > > > > classloader behavior, and a separate
> > > config/support
> > > > > > > > surface.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > So I do not think this is ready to move forward
> > > as
> > > > > just
> > > > > > > > > > “another
> > > > > > > > > > > > JDBC
> > > > > > > > > > > > > > > > configuration option.”
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Before I would consider this mergeable, I think
> > > we
> > > > > need
> > > > > > > > > > explicit
> > > > > > > > > > > > > > > agreement
> > > > > > > > > > > > > > > > on the contract:
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 1. Is Polaris-managed JDBC only a narrow escape
> > > > hatch
> > > > > > for
> > > > > > > > > > > > > > > runtime-provided
> > > > > > > > > > > > > > > > driver jars, or a peer supported datasource
> > path?
> > > > > > > > > > > > > > > > 2. Which Quarkus/Agroal integrations are
> > > > > intentionally
> > > > > > > not
> > > > > > > > > > > > available
> > > > > > > > > > > > > on
> > > > > > > > > > > > > > > > that path?
> > > > > > > > > > > > > > > > 3. What lifecycle does Polaris own for pools,
> > > > loaded
> > > > > > > > drivers,
> > > > > > > > > > > > > shutdown,
> > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > driver upgrades?
> > > > > > > > > > > > > > > > 4. Is this meant to be part of future per-realm
> > > > > > > datasource
> > > > > > > > > > routing?
> > > > > > > > > > > > > If
> > > > > > > > > > > > > > > so,
> > > > > > > > > > > > > > > > I think that needs a separate design
> > discussion.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Until that contract is agreed, I do not think
> > we
> > > > > should
> > > > > > > > present
> > > > > > > > > > > > this
> > > > > > > > > > > > > as a
> > > > > > > > > > > > > > > > second supported JDBC path or treat the PR as
> > > > > mergeable
> > > > > > > > with
> > > > > > > > > > > > > > > documentation
> > > > > > > > > > > > > > > > updates alone.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > On Tue, Jul 7, 2026 at 3:48 AM Dmitri
> > > Bourlatchkov
> > > > <
> > > > > > > > > > > > [email protected]
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Hi Yufei,
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Thanks for the update. That approach to
> > loading
> > > > the
> > > > > > > > driver
> > > > > > > > > > can
> > > > > > > > > > > > > work, I
> > > > > > > > > > > > > > > > > think.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > However, I'm not sure whether it is
> > preferable
> > > > to a
> > > > > > > > proper
> > > > > > > > > > > > Quarkus
> > > > > > > > > > > > > > > > > downstream build.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Adding jars to Polaris still requires some
> > form
> > > > of
> > > > > > > > downstream
> > > > > > > > > > > > > build,
> > > > > > > > > > > > > > > > > whether it is tar-based or docker-based.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Performing a full Quarkus build downstream
> > > offers
> > > > > > some
> > > > > > > > > > > > advantages,
> > > > > > > > > > > > > > > > though:
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > * Integration tests can be executed with the
> > > > > specific
> > > > > > > > driver.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > * Dependencies are resolved / validated at
> > > build
> > > > > > time.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > * Quarkus manages the DataSource lifecycle.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > I wonder what other people think too.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Cheers,
> > > > > > > > > > > > > > > > > Dmitri.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > On Mon, Jul 6, 2026 at 9:22 PM Yufei Gu <
> > > > > > > > > > [email protected]>
> > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Hi Dmitri,
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Good catch. The initial POC only proved the
> > > > > driver
> > > > > > > > works if
> > > > > > > > > > > > it’s
> > > > > > > > > > > > > > > > already
> > > > > > > > > > > > > > > > > > visible to the runtime classloader.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > I updated the approach so the
> > Polaris-managed
> > > > > JDBC
> > > > > > > > > > datasource
> > > > > > > > > > > > can
> > > > > > > > > > > > > > > load
> > > > > > > > > > > > > > > > > > driver jars explicitly before creating
> > > Hikari.
> > > > In
> > > > > > the
> > > > > > > > > > binary
> > > > > > > > > > > > > > > > > distribution,
> > > > > > > > > > > > > > > > > > users can drop jars into:
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > server/jdbc-drivers/
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > For admin-tool bootstrap/purge, the same
> > > > applies
> > > > > > > under:
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > admin/jdbc-drivers/
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > They can also override the location with:
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> > polaris.persistence.relational.jdbc.driver-directory=/path/to/jdbc-drivers
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > So this does not depend on adding jars to
> > > > > lib/main
> > > > > > or
> > > > > > > > > > > > rebuilding
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > Quarkus fast-jar metadata. The jar just
> > needs
> > > > to
> > > > > be
> > > > > > > > present
> > > > > > > > > > > > > before
> > > > > > > > > > > > > > > > > Polaris
> > > > > > > > > > > > > > > > > > creates the datasource.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Yufei
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > On Mon, Jul 6, 2026 at 3:25 PM Dmitri
> > > > > Bourlatchkov
> > > > > > <
> > > > > > > > > > > > > [email protected]
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Hi Yufei,
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Could you provide some more details about
> > > how
> > > > > > > > exactly a
> > > > > > > > > > 3rd
> > > > > > > > > > > > > party
> > > > > > > > > > > > > > > > JDBC
> > > > > > > > > > > > > > > > > > > driver is incorporated into Polaris? I
> > > might
> > > > > have
> > > > > > > > missed
> > > > > > > > > > that
> > > > > > > > > > > > > in
> > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > PR,
> > > > > > > > > > > > > > > > > > > but it was not apparent to me at first
> > > > reading.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > > > Dmitri.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > On Mon, Jul 6, 2026 at 6:22 PM Yufei Gu <
> > > > > > > > > > > > [email protected]>
> > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > Hi all,
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > I put together a small POC(
> > > > > > > > > > > > > > > > > https://github.com/apache/polaris/pull/4984
> > > > > > > > > > > > > > > > > > )
> > > > > > > > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > > > > the relational JDBC backend so Polaris
> > > can
> > > > > > create
> > > > > > > > its
> > > > > > > > > > own
> > > > > > > > > > > > > JDBC
> > > > > > > > > > > > > > > > > > datasource
> > > > > > > > > > > > > > > > > > > > from config, instead of always relying
> > on
> > > > the
> > > > > > > > Quarkus
> > > > > > > > > > > > > datasource.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > The config looks like this:
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > >
> > > > > polaris.persistence.relational.jdbc.jdbc-url=jdbc:postgresql://...
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > polaris.persistence.relational.jdbc.driver=org.postgresql.Driver
> > > > > > > > > > > > > > > > > > > >
> > > > > > polaris.persistence.relational.jdbc.username=...
> > > > > > > > > > > > > > > > > > > >
> > > > > > polaris.persistence.relational.jdbc.password=...
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > If jdbc-url is set, Polaris creates and
> > > > owns
> > > > > > the
> > > > > > > > Hikari
> > > > > > > > > > > > > > > datasource.
> > > > > > > > > > > > > > > > > If
> > > > > > > > > > > > > > > > > > it
> > > > > > > > > > > > > > > > > > > > is not set, we keep using the existing
> > > > > Quarkus
> > > > > > > > > > datasource
> > > > > > > > > > > > > path.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > I also added tests showing that:
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >    - We can create datasources
> > > dynamically
> > > > > from
> > > > > > > > config
> > > > > > > > > > > > > > > > > > > >    - Different configurations can
> > create
> > > > > > > > independent
> > > > > > > > > > > > > datasources,
> > > > > > > > > > > > > > > > > which
> > > > > > > > > > > > > > > > > > > >    could help future per-realm
> > datasource
> > > > > > support
> > > > > > > > > > > > > > > > > > > >    - A JDBC driver can be supplied at
> > > > runtime
> > > > > > > from
> > > > > > > > a
> > > > > > > > > > jar
> > > > > > > > > > > > > instead
> > > > > > > > > > > > > > > of
> > > > > > > > > > > > > > > > > > being
> > > > > > > > > > > > > > > > > > > >    on the build-time classpath. This is
> > > > very
> > > > > > > > helpful
> > > > > > > > > > for
> > > > > > > > > > > > > > > > proprietary
> > > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > >    Apache license-incompatible drivers,
> > > > like
> > > > > > > MySQL.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > This POC does not yet implement full
> > > > > per-realm
> > > > > > > > > > datasource
> > > > > > > > > > > > > > > routing.
> > > > > > > > > > > > > > > > It
> > > > > > > > > > > > > > > > > > > only
> > > > > > > > > > > > > > > > > > > > demonstrates the lower-level building
> > > > blocks:
> > > > > > > > Polaris
> > > > > > > > > > can
> > > > > > > > > > > > > create
> > > > > > > > > > > > > > > > > > managed
> > > > > > > > > > > > > > > > > > > > JDBC pools from config, multiple pools
> > > can
> > > > be
> > > > > > > > created
> > > > > > > > > > > > > > > > independently,
> > > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > > the JDBC driver can be supplied at
> > > runtime.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > Feedback is welcome before I turn this
> > > > into a
> > > > > > > > formal
> > > > > > > > > > PR.
> > > > > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > > > > Yufei
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >

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