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 > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > >
