+1 for Steven's suggestion to target the LTS + two latest Flink releases. >My previous experience suggests that during upgrades it is usually better to >change only one thing at a time.
@Peter Not optimal, but if we skipped newer Flink versions to preserve the older versions, what do we tell users of newer Flink versions? Ideally, we would retain support for a given Flink version throughout Iceberg releases for as long as possible, but we have to strike a balance. That said, we could start supporting more than three Flink versions. In that case we need to tune the build matrix a bit, to prevent building all Flink versions for every change. I just noticed that we always build and test all the versions, even if we do not touch files for an older Flink version. I wonder whether we could support older Flink versions a bit more compact, e.g. using a diff against the latest Flink version. The copy approach is a bit error-prone and hard to review. The actual changes between Flink versions are usually small. -Max On Wed, May 27, 2026 at 7:29 AM Péter Váry <[email protected]> wrote: > > I have some concerns, that with the proposed new support matrix forces users > to upgrade Flink and Iceberg versions at the same time. > > My previous experience suggests that during upgrades it is usually better to > change only one thing at a time. > > Do others share my concerns? > > > On Wed, May 27, 2026, 02:42 Steven Wu <[email protected]> wrote: >> >> Talat, thanks for working on the 2.2 support. >> >> Please follow the previous PR regarding the version upgrade. Similarly, we >> want 4 or 5 commits that should be preserved via `Rebase and merge` >> https://github.com/apache/iceberg/pull/13714/commits >> >> >> >> On Tue, May 26, 2026 at 5:26 PM Talat Uyarer via dev >> <[email protected]> wrote: >>> >>> Thank you, Steve, for the discussion email. It was my initial thought as >>> well to keep Flink 1.20, as the transition from 1.20 to 2.0 represents a >>> significant change for the Flink ecosystem. >>> >>> If there are no objections, I will create a PR to drop Flink 2.0 support >>> and add Flink 2.2 instead. I previously opened a 2.2 PR before the recent >>> Iceberg 1.11.0 release (https://github.com/apache/iceberg/pull/15476), so I >>> will rebase and refresh that work. >>> >>> >>> On Tue, May 26, 2026 at 8:57 AM Kevin Liu <[email protected]> wrote: >>>> >>>> > 1.12.0: support Flink 1.20, 2.2, 2.3 >>>> >>>> That makes sense. I think it's a good idea to have an >>>> iceberg-flink-runtime for each Flink release, even if it's only for 1 >>>> Iceberg release. >>>> >>>> We should also update the Multi-engine support - Flink [1] page and mark >>>> them as "Deprecated". I think many users use that page for the source of >>>> truth. >>>> >>>> [1] https://iceberg.apache.org/multi-engine-support/#apache-flink >>>> >>>> >>>> >>>> On Tue, May 26, 2026 at 7:15 AM Steven Wu <[email protected]> wrote: >>>>> >>>>> Jacky, thanks a lot for sharing the observations. >>>>> >>>>> I agree with prioritizing support for Flink 2.2.0. With Flink 2.3.0 >>>>> release coming soon (most likely before the next Iceberg 1.12.0), I >>>>> propose dropping the support for 2.1.0 when adding 2.3.0. >>>>> >>>>> So here is the revised support matrix. >>>>> 1.11.0: support Flink 1.20, 2.0, 2.1 >>>>> 1.12.0: support Flink 1.20, 2.2, 2.3 >>>>> >>>>> Iceberg 1.12.0 would likely be 2-3 months away following our targeted >>>>> regular cadence. >>>>> >>>>> >>>>> On Tue, May 26, 2026 at 12:11 AM Jacky Lee <[email protected]> wrote: >>>>>> >>>>>> +1 for retaining Flink 1.20 support. >>>>>> >>>>>> Regarding whether to skip 2.2.0 and jump directly to 2.3.0, I'd like to >>>>>> share some observations from the Flink ecosystem side that may be useful >>>>>> for this discussion. >>>>>> >>>>>> Our team has been working on a Flink version upgrade recently, and >>>>>> during this process we noticed the following: the Flink Connector >>>>>> community is currently maintaining primarily 2.0.0 and 2.2.0, while >>>>>> 2.1.0 has effectively been skipped and is not part of the connector's >>>>>> mainstream support matrix. As for 2.3.0, it has not yet been officially >>>>>> released, so integration work cannot proceed at this stage. >>>>>> >>>>>> In addition, I've discussed the version selection question with several >>>>>> Flink PMC members, and the consistent recommendation has been to skip >>>>>> 2.1.0 and adopt 2.2.0 directly. Looking at the Flink community's current >>>>>> maintenance focus and user adoption, 2.2.0 clearly offers broader >>>>>> ecosystem compatibility and stronger community support compared to 2.1.0. >>>>>> >>>>>> Based on the above, I'd lean toward the following approach: >>>>>> >>>>>> Prioritize support for Flink 2.2.0, aligning with the Flink Connector >>>>>> community's mainline direction, so that users running Iceberg + Flink >>>>>> can benefit from the most complete ecosystem support; >>>>>> Track the 2.3.0 release in parallel, and move forward with integration >>>>>> once it is officially released — this can be planned as a follow-up >>>>>> milestone; >>>>>> Defer 2.1.0 support for now, to avoid spreading maintenance resources >>>>>> too thin. >>>>>> >>>>>> >>>>>> That said, the final decision should still factor in Iceberg's overall >>>>>> maintenance capacity and the actual needs of our user base. Looking >>>>>> forward to hearing further thoughts from the community. >>>>>> >>>>>> >>>>>> Steven Wu <[email protected]> 于2026年5月26日周二 14:03写道： >>>>>>> >>>>>>> Hi everyone, >>>>>>> >>>>>>> There is an ongoing discussion in PR #16517 about how we want to manage >>>>>>> Flink version support for the next release. >>>>>>> >>>>>>> >>>>>>> The current PR proposes removing Flink 1.20 support now that Iceberg >>>>>>> 1.11.0 is out and Flink 2.1 support has been added. However, the PR >>>>>>> discussion raised a few broader questions that seem worth deciding on >>>>>>> the dev list. >>>>>>> >>>>>>> >>>>>>> The main points raised so far are: >>>>>>> >>>>>>> Should we really drop Flink 1.20 next? Flink 1.20 is an LTS release and >>>>>>> has a longer support window. If we remove one older Flink version, >>>>>>> Flink 2.0 may be the better candidate to drop instead of 1.20. >>>>>>> >>>>>>> Which new Flink version should we add next? There was earlier work for >>>>>>> Flink 2.2, but because Iceberg 1.11.0 took a while to release and Flink >>>>>>> 2.3 is already out, it may be worth considering whether we should skip >>>>>>> 2.2 and move directly to 2.3 instead. >>>>>>> >>>>>>> >>>>>>> My proposed approach would result in supporting versions 1.20, 2.1, and >>>>>>> 2.3 in the next Iceberg release:12.0 release. >>>>>>> >>>>>>> Keep Flink 1.20 for longer and drop Flink 2.0 instead. >>>>>>> Jump directly to Flink 2.3 and skip 2.2. >>>>>>> >>>>>>> >>>>>>> What do others think? >>>>>>> >>>>>>> >>>>>>> Thanks, >>>>>>> Steven >>>>>>> >>>>>>>
