I guess a first adopter could be to pick some size configurable thread pool to migrate. remove the config and use virtual threads. Stating that the initial win is reducing cognitive load for an operator by replacing config choices with virtual threads wherever possible. Perhaps the pool in LookupReferencesManager if we had to pick something.
On Tue, Apr 14, 2026 at 12:33 PM Clint Wylie <[email protected]> wrote: > +1 from me, I also would like to explore using virtual threads as soon > as possible (without the overhead of trying to build multi-release > jars), and java 25 is my real wish for our minimum supported version > too so we can at least have all the nice memory stuff from the ffi > > On Tue, Apr 14, 2026 at 9:52 AM Jesse Tuğlu <[email protected]> wrote: > > > > > Is there any place you have in mind where you are eager leverage > > Java 21 language features? > > > > This will allow for things like green (virtual) threads and JDK 25 will > > allow for things like FFI, which will help move along the goals mentioned > > in: https://github.com/apache/druid/issues/19039. > > > > > Regarding java25, is that your analysis from initial inspection the > Hadoop > > docs/code or did you smoke check the compatibility at runtime too? > > > > I've run JDK 25 on JDK 21-compiled bytecode internally on a test cluster > > and have validated it passes CI. I believe the prior blockers for running > > JDK 25 were the incompatibilities with SecurityManager brought in by > older > > versions of Hadoop. > > > > On Tue, Apr 14, 2026 at 7:47 AM Lucas Capistrant < > [email protected]> > > wrote: > > > > > Thanks for starting the thread, Jesse. I think this is a great idea for > > > Druid 38. Is there any place you have in mind where you are eager > leverage > > > Java 21 language features? A good motivation to share with the change > > > notice helps communicate the benefit of updating our Java support > matrix. > > > Regardless, I’m on board with it. > > > > > > Regarding java25, is that your analysis from initial inspection the > Hadoop > > > docs/code or did you smoke check the compatibility at runtime too? > > > > > > Thanks, > > > Lucas > > > > > > On Tue, Apr 14, 2026 at 12:08 AM Jesse Tuğlu <[email protected]> wrote: > > > > > > > Hi folks, > > > > > > > > Wanted to start a devlist thread to discuss removal of JDK 17 in > favor of > > > > JDK 21/25 as supported runtimes in Druid 38. The PR for this change > is > > > > here: https://github.com/apache/druid/pull/19304. Upgrading to > Hadoop > > > 3.5 > > > > clients enabled <https://hadoop.apache.org/docs/r3.5.0/> the use of > JDK > > > 21 > > > > and, from what I can tell, contains SecurityManager patches that > unblock > > > > Druid's usage of JDK 25. > > > > > > > > Best, > > > > > > > > Jesse > > > > > > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [email protected] > For additional commands, e-mail: [email protected] > >
