Hi Dongjoon, If this is a policy issue that necessitates a breaking change, then sure, let’s proceed. I don’t have a strong opinion on this specific case, but I’m more concerned with the broader approach to breaking changes.
I’m referencing this statement from the Spark Version Policy <https://spark.apache.org/versioning-policy.html>: "The Spark project strives to avoid breaking APIs or silently changing behavior, even in major versions." Defining what constitutes a necessary breaking change can be tricky, and discussions like this on the dev list are valuable for building consensus. Thanks to Dongjoon for starting this discussion, and I encourage all of us to do it for other breaking changes as well. Thanks, Wenchen On Wed, Feb 19, 2025 at 12:56 PM Dongjoon Hyun <dongj...@apache.org> wrote: > I have different perspectives from Wenchen's opinion in three ways. > > > I’d like to emphasize that a major version release is not a justification > > for unnecessary breaking changes. > > ...the period between 3.5.5 and 4.0.0 likely isn’t long enough. > > First, it's an inevitably necessary change to protect Apache Spark > repository from a 3rd-party company's configuration because Apache Spark > repository is not owned by that 3rd-party company. We can fix this mistake > in Spark 4. > > Second, Apache Spark follows the Semantic Versioning. By definition, we > can fix this only at Apache Spark 4.0.0. Otherwise, maybe 6 years later > with Spark 5? > > Third, Apache Spark 3.5.x has an extended support period until April 12th > 2026. That's the reason why we should rename the configuration while > keeping `spark.databricks.*` as an alternative name for next 14 months. > Apache Spark 4.0.0 release is a major-version release which is different > from maintenance versions like 3.5.5. Spark 4.0 is not enforcing the > customers to migrate immediately. It means the customers have their own > timeframe which is independent from Apache Spark release cadence. > > Additionally, for the following, although I'm not sure who is *you* in > this context, Wenchen's proposal sounds clearly different from what this > thread proposed. In other words, I proposed we should not keep the legacy > support in 4.0 and we should not remove that config in 3.5.5. > > > Personally I think we should keep the legacy support in 4.0 as it's just > a > > few lines of code, but if no one uses this conf and you have a strong > > opinion on this cleanup, let's remove the wrongly named conf in both > 3.5.5 > > and 4.0.0. > > To be clear, I'd like to emphasize the followings: > - It's not about just a few lines of code. It's more like a policy-side > issue which we are supposed to keep in Apache Spark repository so far and > in the future. > - All exposed configurations should be considered as used by someone > already if there is no evidence. > > Sincerely, > Dongjoon. > > On 2025/02/19 03:36:13 Wenchen Fan wrote: > > Hi all, > > > > I’d like to emphasize that a major version release is not a justification > > for unnecessary breaking changes. If we are confident that no one is > using > > this configuration, we should clean it up in 3.5.5 as well. However, if > > there’s a possibility that users are already relying on it, then legacy > > support should be in 4.0 as well. We can remove the legacy support after > a > > reasonable period, though the exact timeline is not yet defined, but the > > period between 3.5.5 and 4.0.0 likely isn’t long enough. > > > > Personally I think we should keep the legacy support in 4.0 as it's just > a > > few lines of code, but if no one uses this conf and you have a strong > > opinion on this cleanup, let's remove the wrongly named conf in both > 3.5.5 > > and 4.0.0. > > > > On Wed, Feb 19, 2025 at 9:03 AM Mich Talebzadeh < > mich.talebza...@gmail.com> > > wrote: > > > > > Depends how you want to play this. As usual a cost/benefit analysis > will > > > be useful > > > > > > *Immediate Removal in Spark 3.5.5*: > > > pros: Quickly removes the problematic configuration, reducing technical > > > debt and potential issues. > > > cons: Users upgrading directly from earlier versions to Spark 3.5.5 or > > > later will face immediate breakage without a deprecation period. > > > > > > *Deprecation in Spark 3.5.5 and Removal in Spark 4.0.0:* > > > pros: Provides a clear deprecation period, allowing users to migrate > their > > > configurations. Reduces the risk of breakage for users who follow > > > recommended upgrade paths. > > > cons: Users who skip versions might still face issues. The depreciation > > > period might be seen as too short if Spark 4.0.0 is released soon after > > > Spark 3.5.5, most probably > > > > > > *Extended Deprecation Period:* > > > pros: Provides a longer migration window, reducing the risk of breakage > > > for users who jump versions. > > > cons: Delays the removal of the configuration, potentially prolonging > > > technical challenges and issues related to the deprecated > configuration. > > > > > > *My take* > > > > > > 1. Deprecate in Spark 3.5.5: Introduce deprecation warnings in Spark > > > 3.5.5 that the spark.databricks.* configuration will be removed in > Spark > > > 4.0.0. > > > 2. Remove in Spark 4.0.0: Remove the configuration in Spark 4.0.0, > > > providing a clear upgrade path and sufficient notice for users to > migrate. > > > 3. User Communication: Ensure that deprecation warnings are > prominent > > > in the documentation, release notes, and runtime logs. Recommend > upgrading > > > through intermediate versions to avoid breakage. > > > > > > HTH > > > > > > Dr Mich Talebzadeh, > > > Architect | Data Science | Financial Crime | Forensic Analysis | GDPR > > > > > > view my Linkedin profile > > > <https://www.linkedin.com/in/mich-talebzadeh-ph-d-5205b2/> > > > > > > > > > > > > > > > > > > On Wed, 19 Feb 2025 at 00:41, Jungtaek Lim < > kabhwan.opensou...@gmail.com> > > > wrote: > > > > > >> Though if we are OK with disturbing users to read the migration guide > to > > >> figure out the change for the case of direct upgrade to Spark 4.0.0+, > I > > >> agree this is also one of the valid ways. > > >> > > >> On Wed, Feb 19, 2025 at 9:20 AM Jungtaek Lim < > > >> kabhwan.opensou...@gmail.com> wrote: > > >> > > >>> The point is, why can't we remove it from Spark 3.5.5 as well if we > are > > >>> planning to "remove" (not deprecate) at the very next minor release? > > >>> > > >>> The logic of migration just works without having the incorrect config > > >>> key to be indicated with SQL config key. > > >>> > > >>> That said, the point we debate here is only valid when we want to let > > >>> users keep setting the value of the config manually for some time. > I'd > > >>> argue users would never set this manually, but let's put this aside > for now. > > >>> > > >>> What is the proper "some time" here? If we deprecate this in Spark > 3.5.5 > > >>> and remove it to Spark 4.0.0, we are going to break the case of > setting the > > >>> config manually when they are upgrading Spark 3.5.4 to Spark 4.0.0 > > >>> directly. I have no idea how we construct the message to recommend > > >>> upgrading from Spark 3.5.4 to Spark 3.5.5, but if it's not strong > enough, > > >>> there will always be a case who directly jumps major/minor versions, > and > > >>> for them, effectively we do not deprecate the config very well. > > >>> > > >>> I suspect there would be a huge difference if we just remove it in > Spark > > >>> 3.5.5 and only support the migration case. That has been something I > > >>> claimed if we really want to kick the incorrect config out ASAP. If > we want > > >>> to do this gracefully, I don't feel like removing this in Spark > 4.0.0 is > > >>> giving users enough time to indicate the config is deprecated and > will be > > >>> removed very soon. > > >>> > > >>> On Wed, Feb 19, 2025 at 2:24 AM Holden Karau <holden.ka...@gmail.com > > > > >>> wrote: > > >>> > > >>>> I think that removing in 4 sounds reasonable to me as well. It’s > > >>>> important to create a sense of fairness among vendors. > > >>>> > > >>>> Twitter: https://twitter.com/holdenkarau > > >>>> Fight Health Insurance: https://www.fighthealthinsurance.com/ > > >>>> <https://www.fighthealthinsurance.com/?q=hk_email> > > >>>> Books (Learning Spark, High Performance Spark, etc.): > > >>>> https://amzn.to/2MaRAG9 <https://amzn.to/2MaRAG9> > > >>>> YouTube Live Streams: https://www.youtube.com/user/holdenkarau > > >>>> Pronouns: she/her > > >>>> > > >>>> > > >>>> On Tue, Feb 18, 2025 at 11:22 AM Dongjoon Hyun < > dongjoon.h...@gmail.com> > > >>>> wrote: > > >>>> > > >>>>> I don't think there is a reason to keep it at 4.0.0 (and forever?) > if > > >>>>> we release Spark 3.5.5 with the proper deprecation. This is a big > > >>>>> difference, Wenchen. > > >>>>> > > >>>>> And, the difference is the main reason why I initiated this thread > to > > >>>>> sugguest to remove 'spark.databricks.*' completely from Apache > Spark 4 via > > >>>>> volunteering Spark 3.5.5 release manager. > > >>>>> > > >>>>> Sincerely, > > >>>>> Dongjoon > > >>>>> > > >>>>> > > >>>>> On Mon, Feb 17, 2025 at 22:59 Wenchen Fan <cloud0...@gmail.com> > wrote: > > >>>>> > > >>>>>> It’s unfortunate that we missed identifying these issues during > the > > >>>>>> code review. However, since they have already been released, I > believe > > >>>>>> deprecating them is a better approach than removing them, as the > latter > > >>>>>> would introduce a breaking change. > > >>>>>> > > >>>>>> Regarding Jungtaek’s PR < > https://github.com/apache/spark/pull/49983>, > > >>>>>> it looks like there are only a few lines of migration code. Would > it be > > >>>>>> acceptable to leave them for legacy support? With the new config > name style > > >>>>>> check rule in place, such issues should not occur again in the > future. > > >>>>>> > > >>>>>> On Tue, Feb 18, 2025 at 9:00 AM Jungtaek Lim < > > >>>>>> kabhwan.opensou...@gmail.com> wrote: > > >>>>>> > > >>>>>>> I think I can add a color to minimize the concern. > > >>>>>>> > > >>>>>>> The problematic config we added is arguably not user facing. I'd > > >>>>>>> argue moderate users wouldn't even understand what the flag is > doing. The > > >>>>>>> config was added because Structured Streaming has been > leveraging SQL > > >>>>>>> config to "do the magic" on having two different default values > for new > > >>>>>>> query vs old query (checkpoint is created from the version where > the fix is > > >>>>>>> not landed). This is purely used for backward compatibility, not > something > > >>>>>>> we want to give users flexibility. > > >>>>>>> > > >>>>>>> That said, I don't see a risk of removing config "at any point". > > >>>>>>> (I'd even say removing this config in Spark 3.5.5 does not > change anything. > > >>>>>>> The reason I'm not removing the config in 3.5 (and yet to > 4.0/master) is > > >>>>>>> just to address any concern on being conservative.) > > >>>>>>> > > >>>>>>> I think you are worrying about case 1 from my comment. From my > new > > >>>>>>> change (link <https://github.com/apache/spark/pull/49983>), I > made > > >>>>>>> a migration logic when the offset log contains the problematic > > >>>>>>> configuration - we will take the value, but put the value to the > new > > >>>>>>> config, and at the next microbatch planning, the offset log will > contain > > >>>>>>> the new configuration going forward. This addresses the case 1, > as long as > > >>>>>>> we retain the migration logic for a couple minor releases (say, > 4.2 or so). > > >>>>>>> We just need to support this migration logic for the time where > we never > > >>>>>>> thought of jumping directly from Spark 3.5.4 to the version. > > >>>>>>> > > >>>>>>> Hope this helps to address your concern/worrying. > > >>>>>>> > > >>>>>>> > > >>>>>>> On Tue, Feb 18, 2025 at 7:40 AM Bjørn Jørgensen < > > >>>>>>> bjornjorgen...@gmail.com> wrote: > > >>>>>>> > > >>>>>>>> > > >>>>>>>> Having breaking changes in a minor seems not that good.. As I'm > > >>>>>>>> reading this, > > >>>>>>>> > > >>>>>>>> "*This could break the query if the rule impacts the query, > > >>>>>>>> because the effectiveness of the fix is flipped.*" > > >>>>>>>> > https://github.com/apache/spark/pull/49897#issuecomment-2652567140 > > >>>>>>>> > > >>>>>>>> > > >>>>>>>> What if we have this https://github.com/apache/spark/pull/48149 > > >>>>>>>> change in the branch and remove it only for version 4? That way > we dont > > >>>>>>>> break anything. > > >>>>>>>> > > >>>>>>>> > > >>>>>>>> > > >>>>>>>> > > >>>>>>>> man. 17. feb. 2025 kl. 23:03 skrev Dongjoon Hyun < > > >>>>>>>> dongjoon.h...@gmail.com>: > > >>>>>>>> > > >>>>>>>>> Hi, All. > > >>>>>>>>> > > >>>>>>>>> I'd like to highlight this discussion because this is more > > >>>>>>>>> important and tricky in a way. > > >>>>>>>>> > > >>>>>>>>> As already mentioned in the mailing list and PRs, there was an > > >>>>>>>>> obvious mistake > > >>>>>>>>> which missed an improper configuration name, > `spark.databricks.*`. > > >>>>>>>>> > > >>>>>>>>> > > >>>>>>>>> > https://github.com/apache/spark/blob/a6f220d951742f4074b37772485ee0ec7a774e7d/sql/catalyst/src/main/scala/org/apache/spark/sql/internal/SQLConf.scala#L3424 > > >>>>>>>>> > > >>>>>>>>> > > >>>>>>>>> > `spark.databricks.sql.optimizer.pruneFiltersCanPruneStreamingSubplan` > > >>>>>>>>> > > >>>>>>>>> In fact, Apache Spark committers have been preventing this > > >>>>>>>>> repetitive mistake > > >>>>>>>>> pattern during the review stages successfully until we slip the > > >>>>>>>>> following backportings > > >>>>>>>>> at Apache Spark 3.5.4. > > >>>>>>>>> > > >>>>>>>>> https://github.com/apache/spark/pull/45649 > > >>>>>>>>> https://github.com/apache/spark/pull/48149 > > >>>>>>>>> https://github.com/apache/spark/pull/49121 > > >>>>>>>>> > > >>>>>>>>> At this point of writing, `spark.databricks.*` was removed > > >>>>>>>>> successfully from `master` > > >>>>>>>>> and `branch-4.0` and a new ScalaStyle rule was added to protect > > >>>>>>>>> Apache Spark repository > > >>>>>>>>> from future mistakes. > > >>>>>>>>> > > >>>>>>>>> SPARK-51172 Rename to > > >>>>>>>>> spark.sql.optimizer.pruneFiltersCanPruneStreamingSubplan > > >>>>>>>>> SPARK-51173 Add `configName` Scalastyle rule > > >>>>>>>>> > > >>>>>>>>> What I proposed is to release Apache Spark 3.5.5 next week with > > >>>>>>>>> the deprecation > > >>>>>>>>> in order to make Apache Spark 4.0 be free of > `spark.databricks.*` > > >>>>>>>>> configuration. > > >>>>>>>>> > > >>>>>>>>> Apache Spark 3.5.5 (2025 February, with deprecation warning > with > > >>>>>>>>> alternative) > > >>>>>>>>> Apache Spark 4.0.0 (2025 March, without `spark.databricks.*` > > >>>>>>>>> config) > > >>>>>>>>> > > >>>>>>>>> In addition, I'd like to volunteer as a release manager of > Apache > > >>>>>>>>> Spark 3.5.5 > > >>>>>>>>> for a swift release. WDYT? > > >>>>>>>>> > > >>>>>>>>> FYI, `branch-3.5` has 37 patches currently. > > >>>>>>>>> > > >>>>>>>>> $ git log --oneline v3.5.4..HEAD | wc -l > > >>>>>>>>> 37 > > >>>>>>>>> > > >>>>>>>>> Best Regards, > > >>>>>>>>> Dongjoon. > > >>>>>>>>> > > >>>>>>>> > > >>>>>>>> > > >>>>>>>> -- > > >>>>>>>> Bjørn Jørgensen > > >>>>>>>> Vestre Aspehaug 4, 6010 Ålesund > > >>>>>>>> < > https://www.google.com/maps/search/Vestre+Aspehaug+4,+6010+%C3%85lesund++Norge?entry=gmail&source=g > > > > >>>>>>>> Norge > > >>>>>>>> < > https://www.google.com/maps/search/Vestre+Aspehaug+4,+6010+%C3%85lesund++Norge?entry=gmail&source=g > > > > >>>>>>>> > > >>>>>>>> +47 480 94 297 > > >>>>>>>> > > >>>>>>> > > > > --------------------------------------------------------------------- > To unsubscribe e-mail: dev-unsubscr...@spark.apache.org > >
