Gian Merlino

Thanks for reviewing!

> `Grouping#hasGroupingDimensionsDropped` accomplishes something similar like `CTX_HAS_DROPPED_DIMENSIONS`, however it only lives in the SQL layer. I think we can drop `hasGroupingDimensionsDropped` and use the newly added context parameter to avoid...

> I think this PR also enables the following test in MSQ `testCountStarWithLongColumnFiltersOnFloatLiterals` > > These are already supported by MSQ, however marked as `msqIncompatible`. Since they seemed relevant to...

> `COUNT` in SQL initializes to `null`, not `0` as expected, because the null-agg-frame is written with the combining aggregators. The combining aggregator of `count` is `longSum`, which initializes to...

This may be the same issue as described in https://github.com/apache/druid/issues/15936#issuecomment-2881800870. If so, it's a web UI issue, really: the web console code doesn't understand `loadingLookup` or `pollingLookup`, although they work...

Sorry, this one fell through the cracks. Are you still interested in working on it @AlbericByte? If so, please let me know, I will do a review.

@kgyrtkirk shared a core dump and libs archive with me offline. I've attached them to the Azul support case.

> disabling C2 optimization for tests on 21 might also be a possible way out This seems like the best temporary approach. I raised #17456 to attempt it.

Now a quidem test is failing with: ``` *** java.lang.instrument ASSERTION FAILED ***: "!errorOutstanding" with message transform method call failed at src/java.instrument/share/native/libinstrument/JPLISAgent.c line: 884 ``` Maybe JDK 21 is too...

> Switching the JDK distribution to `temurin` in [#17449](https://github.com/apache/druid/pull/17449) seems to not have the segfaults seen in the JDK 21 tests, at least in the four repeated CI runs. Any...