Hi, Timo & Martijn, Sorry for the late reply, thanks for the feedback.
I strongly agree that the best solution would be to cooperate more with the Calcite community and maintain all new features and bug fixes in the Calcite community, without any forking. It is a long-term process. I think it's difficult to change community rules, because the Calcite project is a neutral lib that serves multiple projects simultaneously. I don't think fork calcite is the perfect solution, but rather a better balance within limited resources: it's possible to introduce some necessary minor features and bug fixes without having to upgrade to the latest version. I investigate other projects that use Calcite[1] and find that most of them do not use the latest version of the Calcite. Even for the Kylin community, the version, based on Calcite-1.16.0 has been updated to 70[2]. (Similar projects are quark and drill) My guess is that these projects choosed a stable version, (or even choose to maintain a fork project), to maintain the stability. When Flink does not need to introduce new syntax anymore, I guess it's less expensive and more manageable to maintain a fork Calcite. Even if we don't end up going the fork calcite route, I hope that we could discuss the options for subsequent calcite upgrades here. Just like Timo mentioned, how to balance feature development and code maintenance. There are a few realistic questions about the Calcite upgrade situation now, such as: 1. If we keep up with the latest version of Calcite, who is responsible for each upgrade? The current status is that no one has motivation to upgrade the version unless he/she wants to drive new features. 2. Do we have the resources/energy to upgrade each version? 3. How do we ensure that each upgrade is expected? It took a lot of effort to verify the correctness of the upgrade results.The Test set for uncommon sql usage is not enough now. > I still don't quite understand why we want to avoid Calcite upgrades. Not every feature in Calcite is a feature we really need. While some refactorings can be very burdensome (lots of bugs, plan changes, and a lot of effort to fix). Just as mentioned above, the "SEARCH operator" refactoring in CALCITE-4173 did cause a lot of bugs. [1] https://calcite.apache.org/docs/powered_by.html [2] https://github.com/Kyligence/calcite/commits/kycalcite-1.16.0.x-4.x Best, Godfrey Martijn Visser <martijnvis...@apache.org> 于2022年4月25日周一 22:11写道： > > Hi all, > > Just a couple of remarks on some of things from this thread: > > > I think we will upgrade Calcite to 1.31 only when Flink depends on some > significant features of Calcite. > > Such as: new syntax PTF (CALCITE-4865). > > Like Timo also mentions, I think this is a bad practice. Calcite is a key > dependency for Flink. We should upgrade as often as possible, not as little > as possible. Any fork in the beginning is easy, but it becomes a bigger > pain as time progresses. > > > >## Are the calcite repository costly to maintain? > > From the experience of @Dann y chen (One PMC of Calcite), publishing > > is much easier. > > Since Calcite is such a key dependency, I would really oppose forking it. > There will only be very few maintainers of such a fork. The amount of > people that know and can maintain both Calcite and Flink will be even less. > > > I'm just trying to find an approach which can avoid frequent Calcite > upgrades, > > but easily support bug fix and minor new feature development. > > I still don't quite understand why we want to avoid Calcite upgrades. > Upgrading Calcite introduces new features, but it also resolves bugs that > currently exist in Flink. Part of housekeeping is that we keep our codebase > up-to-date and tidy, to avoid that it becomes a mess and unmaintainable. I > understand that this is less preferred, because you can't spend this time > working on new features. If I make a comparison with doing construction > work on your house, you can't put in a new floor if you don't clean out the > room first. > > > About Calcite version upgrading, we should try not use the latest > Calcite version to avoid the bugs introduced by the new version if possible. > > I can fully agree on that. But right now we're running multiple versions > behind. > > Have we reached out to the Calcite community first with our problems, or > have we gone straight into "let's fork it"? > > I still haven't seen an argument that would make me in favor of setting up > a fork. > > Best regards, > > Martijn > > On Mon, 25 Apr 2022 at 15:55, Timo Walther <twal...@apache.org> wrote: > > > Hi Godfrey, > > > > I'm also strictly against maintaining a Calcite fork. We had similar > > discussions during the merge of the Blink code base in the past and I'm > > happy that we could prevent a fork until today. Let me elaborate a bit > > on my strict opinion here: > > > > 1) Calcite does not offer bugfix releases > > > > In the end, also Calcite is an Apache community. I'm sure we could > > improve our collaboration and help releasing bugfix releases. So far we > > were mostly leveraging all the stuff that the Calcite community has > > built. It would be good to strengthen the relation and also give > > something back. > > > > So far having no bugfix releases was not really a problem for the Flink > > community. We simply copy over files from Calcite into Flink once a bug > > has been merged in Calcite. Maven implicitly overwrites the original > > Calcite classes during artifact building. Most `org.apache.calcite` > > classes in the Flink code base are fixing bugs and wait for removal > > during the next Calcite upgrade. > > > > 2) Slow feature reviewing > > > > Slow feature reviewing has a good and a bad side. One of the reasons why > > it is so slow is because the maintainers pay a lot of attention to > > standard compliance, long-term code quality, and > > cross-downstream-projects usability. All of that is the reason why the > > Calcite code base has last multiple decades already and is useful for > > many parties. > > > > Relying on Calcite has protected the Flink code base from merging > > non-standard SQL features and extending the SQL dialect too much. The 1. > > windows in Calcite and aux functions such as TUMBLE_START have shown > > that only standard compliant features should be merged. Now the Flink > > community has the problem of maintaining this custom syntax. > > > > 3) No compatibility guaranteed from the Calcite community > > > > I disagree here. Many changes are protected by keeping deprecated > > methods/constructors/classes around for years. And many refactoring are > > nice also for the Flink community. E.g. easier optimizer rule definition. > > > > IMHO the core problem is rather that we don't update Calcite frequently > > enough. Currently, we are lagging behind quite a bit because we don't > > pay enough resources in code maintenance but only in new feature > > development. We should spend some time in a better balance of the two. > > > > Regards, > > Timo > > > > Am 25.04.22 um 15:13 schrieb godfrey he: > > > Hi Jark, > > > > > > Agree with you, thanks for the feedback. > > > > > > Best, > > > Godfrey > > > > > > Jark Wu <imj...@gmail.com> 于2022年4月25日周一 13:02写道： > > >> Thanks, Godfrey, for starting this discussion, > > >> > > >> I understand the motivation behind it. > > >> No bugfix releases, slow feature reviewing, and no compatibility > > guaranteed > > >> are genuinely blocking the development of Flink SQL. > > >> > > >> I think a fork is the last choice before trying our best to cooperate > > with > > >> the Calcite community. > > >> But we shouldn't stop here if there is no progress. Therefore, I'm okay > > >> with maintaining a fork. > > >> > > >> However: > > >> 1) It should be a temporary solution. We should have a plan to move > > back to > > >> the latest Calcite version at some point (e.g., pushing them to resolve > > the > > >> problems mentioned above). > > >> > > >> 2) If we maintain the fork in flink-extended, we should determine a > > groupId > > >> for deploying to maven central. The community should have permission to > > >> deploy under the groupId. > > >> > > >> Best, > > >> Jark > > >> > > >> > > >> On Sun, 24 Apr 2022 at 16:14, godfrey he <godfre...@gmail.com> wrote: > > >> > > >>> Hi, Jing > > >>> Thanks for sharing the Calcite experiences. > > >>> About Calcite version upgrading, we should try not use the latest > > Calcite > > >>> version to avoid the bugs introduced by the new version if possible. > > >>> This may be a best practice. > > >>> > > >>> > > >>> Hi, Yun > > >>> Thanks for the detailed explanation for the experiences regarding > > FRocksDB. > > >>> I agree with you that the situation with Calcite and RocksDB is a > > >>> little difference. > > >>> The main pain point for Calcite is that we have to upgrade Calcite to > > >>> latest version > > >>> to get fix bugs and new features, but the latest version may be > > >>> unstable, which is a pain for us. > > >>> If we all agree we should maintain a forked Calcite repo, > > >>> there are many experiences we can learn from FRocksDB. > > >>> > > >>> Best, > > >>> Godfrey > > >>> > > >>> Yun Tang <myas...@live.com> 于2022年4月24日周日 11:58写道： > > >>>> Hi all, > > >>>> > > >>>> I could share two cents here for how we maintain FRocksDB. > > >>>> > > >>>> First of all, we also do not prefer to maintain a customized RocksDB > > >>> version in Flink, which brings additional overhead for Flink community: > > >>>> > > >>>> 1. RocksDB community switches to circleci for the CI tests after > > >>> RocksDB-6.x, which requires additional money to run all tests for > > reviewing > > >>> each PR. > > >>>> 2. We need to compile and include all kinds of FRocksDB binaries > > on > > >>> linux32/64, windows, ppc64, ARM and Macos platforms, which is really > > tough > > >>> and boring experiences. > > >>>> The root reason why we have to maintain a forked RocksDB repo is that > > >>> RocksDB community refuses to accept a plugin-like feature based on > > >>> compaction filter, which is heavily dependent by Flink's state TTL > > feature > > >>> [1]. From RocksDB-7.0, the community also moves several components to > > the > > >>> plugin repo [2], although this cannot avoid us to release all kinds of > > >>> binaries, it can at least decrease our energy to maintain the whole > > tests > > >>> if we follow this trend. > > >>>> Last but not least, I don't think current discussion on Apache Calcite > > >>> is in the same situation as FRocksDB. Current Flink SQL guys complain > > that > > >>> Calcite is released too slowly, which blocks some feature development > > in > > >>> Flink. However, RocksDB community itself actually release new versions > > more > > >>> frequently, and we don't rely on its new version for some new features > > >>> currently. Moreover, we're often more careful on upgrading underlying > > >>> storage component as it could impact the performance and data > > correctness. > > >>>> > > >>>> [1] > > >>> > > https://github.com/ververica/frocksdb/commit/3da8249d50c8a3a6ea229f43890d37e098372786 > > >>>> [2] https://github.com/facebook/rocksdb/issues/9390 > > >>>> > > >>>> Best > > >>>> Yun Tang > > >>>> > > >>>> ________________________________ > > >>>> From: Jing Zhang <beyond1...@gmail.com> > > >>>> Sent: Saturday, April 23, 2022 15:21 > > >>>> To: dev <dev@flink.apache.org> > > >>>> Cc: Yun Tang <myas...@live.com> > > >>>> Subject: Re: [DISCUSS] Maintain a Calcite repository for Flink to > > >>> accelerate the development for Flink SQL features > > >>>> Hi Godfrey, > > >>>> I would like to share some problems based on my past experience. > > >>>> 1. It's not easy to push new features in the CALCITE community. > > >>>> As @Martijn referred, > > https://issues.apache.org/jira/browse/CALCITE-4865 > > >>> / > > >>>> https://github.com/apache/calcite/pull/2606 is such an example. > > >>>> I tried out many ways, for example, sent review requests in the dev > > mail > > >>> list, left comments in JIRA and in pull requests. > > >>>> And had to give up finally. Sorry for that. > > >>>> 2. However, some new features of calcite are radical. > > >>>> Such as https://issues.apache.org/jira/browse/CALCITE-4173, which had > > >>> some strong opposition in the CALCITE community, > > >>>> But it was merged finally and caused unexpected problems, such as > > wrong > > >>> results (https://issues.apache.org/jira/browse/FLINK-24708) > > >>>> and other related bugs. > > >>>> 3. Every time we upgrade the calcite version, we will cross multiple > > >>> versions, resulting in a slow upgrade process and > > >>>> uncontrolled results, often causing some unexpected problems. > > >>>> > > >>>> Thank @Godfrey for driving this discussion in a big scope. > > >>>> I think it's a good chance to review these problems and find a > > solution. > > >>>> > > >>>> Best, > > >>>> Jing Zhang > > >>>> > > >>>> godfrey he <godfre...@gmail.com<mailto:godfre...@gmail.com>> > > >>> 于2022年4月22日周五 21:40写道： > > >>>> Hi Chesnay, > > >>>> > > >>>> There is no bug fix version until now. > > >>>> You can find the releases in https://github.com/apache/calcite/tags > > >>>> > > >>>> Best, > > >>>> Godfrey > > >>>> > > >>>> Chesnay Schepler <ches...@apache.org<mailto:ches...@apache.org>> > > >>> 于2022年4月22日周五 18:48写道： > > >>>>> I find it a bit weird that the supposed only way to get a bug fix is > > to > > >>>>> do a big version upgrade. > > >>>>> Is Calcite not creating bugfix releases? > > >>>>> > > >>>>> On 22/04/2022 12:26, godfrey he wrote: > > >>>>>> Thanks for the feedback, guys! > > >>>>>> > > >>>>>> For Jingsong's feedback: > > >>>>>>> ## Do we have the plan to upgrade calcite to 1.31? > > >>>>>> I think we will upgrade Calcite to 1.31 only when Flink depends on > > >>>>>> some significant features of Calcite. > > >>>>>> Such as: new syntax PTF (CALCITE-4865). > > >>>>>> > > >>>>>> >## Is Cherry-pick costly? > > >>>>>> >From the experience of maintaining calcite with our company, the > > >>> cost is small. > > >>>>>> We only cherry-pick the bug fixes and needed minor features. > > >>>>>> For a major feature, we can choose to upgrade the version. > > >>>>>> > > >>>>>>> ## Are the calcite repository costly to maintain? > > >>>>>> >From the experience of @Dann y chen (One PMC of Calcite), > > publishing > > >>>>>> is much easier. > > >>>>>> > > >>>>>> > > >>>>>> For Chesnay's feedback: > > >>>>>> I also totally agree that a fork repository will increase the cost > > of > > >>>>>> maintenance. > > >>>>>> > > >>>>>> Usually, the Calcite community releases a version three months or > > >>> more. > > >>>>>> I think it's hard to let Calcite change the release cycle > > >>>>>> because Calcite supports many compute engines. > > >>>>>> > > >>>>>> > > >>>>>> For Konstantin's feedback: > > >>>>>> Some changes in Calcite may cause hundreds of plan changes in Flink, > > >>>>>> such as: CALCITE-4173. > > >>>>>> We must check whether the change is expected, whether there is > > >>>>>> performance regression. > > >>>>>> Some of the changes are very subtle, especially in the CBO planner. > > >>>>>> This situation also occurs similarly within upgrading from 1.1x to > > >>> 1.22. > > >>>>>> If you are not familiar with Flink planner and Calcite, it will be > > >>>>>> more difficult to upgrade. > > >>>>>> > > >>>>>> > > >>>>>> For Xintong's feedback: > > >>>>>> You are right, I will connect Yun for some help, Thanks for the > > >>> suggestions. > > >>>>>> > > >>>>>> For Martijn's feedback: > > >>>>>> I'm also against cherry-pick many features code into the fock > > >>> repository, > > >>>>>> and I also totally agree we should collaborate closely with the > > >>>>>> Calcite community. > > >>>>>> I'm just trying to find an approach which can avoid frequent Calcite > > >>> upgrades, > > >>>>>> but easily support bug fix and minor new feature development. > > >>>>>> > > >>>>>> As for the CALCITE-4865 case, I think we should upgrade the Calcite > > >>>>>> version to support PTF. > > >>>>>> > > >>>>>> @Jing zhang, can you share some 'feeling' for CALCITE-4865 ? > > >>>>>> > > >>>>>> Best, > > >>>>>> Godfrey > > >>>>>> > > >>>>>> Martijn Visser <martijnvis...@apache.org<mailto: > > >>> martijnvis...@apache.org>> 于2022年4月22日周五 17:31写道： > > >>>>>>> Hi everyone, > > >>>>>>> > > >>>>>>> Overall I'm against the idea of setting up a Calcite fork for the > > >>> same > > >>>>>>> reasons that Chesnay has mentioned. We've talked extensively about > > >>> doing an > > >>>>>>> upgrade of Calcite during the Flink 1.15 release period, but there > > >>> was a > > >>>>>>> lot of pushback by the maintainers against that because of the > > >>> required > > >>>>>>> efforts. Having our own fork will mean that there will be even more > > >>> effort > > >>>>>>> required, because not only do we need to perform the upgrade on > > >>> Flink's > > >>>>>>> end, we also need to maintain this Calcite fork. > > >>>>>>> > > >>>>>>> I think what we should do is have a closer collaboration with the > > >>> Calcite > > >>>>>>> community and see if we can also help out with reviewing/merging > > >>> PRs and > > >>>>>>> more frequent releases. What we're seeing is that already features > > >>> that are > > >>>>>>> proposed towards Calcite because we need them for Flink, are not > > >>> getting > > >>>>>>> picked up by the Calcite community. See > > >>>>>>> https://issues.apache.org/jira/browse/CALCITE-4865 / > > >>>>>>> https://github.com/apache/calcite/pull/2606 which is such an > > >>> example. > > >>>>>>> I would rather invest more in collaborating with the Calcite > > >>> community > > >>>>>>> instead of maintaining our own fork. I believe that would help us > > >>> get new > > >>>>>>> features and bug fixes sooner. > > >>>>>>> > > >>>>>>> Best regards, > > >>>>>>> > > >>>>>>> Martijn Visser > > >>>>>>> https://twitter.com/MartijnVisser82 > > >>>>>>> https://github.com/MartijnVisser > > >>>>>>> > > >>>>>>> > > >>>>>>> On Fri, 22 Apr 2022 at 10:46, Xintong Song <tonysong...@gmail.com > > >>> <mailto:tonysong...@gmail.com>> wrote: > > >>>>>>>> BTW, I think this proposal sounds similar to FRocksDB, the Flink's > > >>> custom > > >>>>>>>> RocksDB build. Maybe folks maintaining FRocksDB can share some > > >>> experiences. > > >>>>>>>> CC @Yun Tang > > >>>>>>>> > > >>>>>>>> Thank you~ > > >>>>>>>> > > >>>>>>>> Xintong Song > > >>>>>>>> > > >>>>>>>> > > >>>>>>>> > > >>>>>>>> On Fri, Apr 22, 2022 at 4:35 PM Xintong Song < > > >>> tonysong...@gmail.com<mailto:tonysong...@gmail.com>> > > >>>>>>>> wrote: > > >>>>>>>> > > >>>>>>>>> Hi Godfrey, > > >>>>>>>>> > > >>>>>>>>> > > >>>>>>>>>> 1. Where to put the code? https://github.com/flink-extended is > > >>> a good > > >>>>>>>>>> place. > > >>>>>>>>> Please notice that `flink-extended` is not endorsed by the Apache > > >>> Flink > > >>>>>>>>> PMC. That means if the proposed new Calcite repository is hosted > > >>> there, > > >>>>>>>> the > > >>>>>>>>> maintenance and release will not be guaranteed by the Apache > > Flink > > >>>>>>>> project. > > >>>>>>>>> I guess the question is do we consider another 3rd party Calcite > > >>>>>>>> repository > > >>>>>>>>> more reliable and convenient than the official Apache Calcite > > >>> that we > > >>>>>>>> want > > >>>>>>>>> to depend on. > > >>>>>>>>> > > >>>>>>>>> Thank you~ > > >>>>>>>>> > > >>>>>>>>> Xintong Song > > >>>>>>>>> > > >>>>>>>>> > > >>>>>>>>> > > >>>>>>>>> On Fri, Apr 22, 2022 at 4:07 PM Chesnay Schepler < > > >>> ches...@apache.org<mailto:ches...@apache.org>> > > >>>>>>>>> wrote: > > >>>>>>>>> > > >>>>>>>>>> I'm overall against the idea of creating a fork. > > >>>>>>>>>> It implies quite some maintenance overhead, like dealing with > > >>> unstable > > >>>>>>>>>> tests, CI, licensing etc. and the overall release overhead. > > >>>>>>>>>> > > >>>>>>>>>> Is there no alternative where we can collaborate more with the > > >>> calcite > > >>>>>>>>>> guys, like verifying new features so bugs are caught sooner? > > >>>>>>>>>> > > >>>>>>>>>> On 22/04/2022 09:31, godfrey he wrote: > > >>>>>>>>>>> Dear devs, > > >>>>>>>>>>> > > >>>>>>>>>>> I would like to open a discussion on the fact that currently > > >>> many > > >>>>>>>>>>> Flink SQL function > > >>>>>>>>>>> development relies on Calcite releases, which seriously > > >>> blocks some > > >>>>>>>>>>> Flink SQL's features release. > > >>>>>>>>>>> Therefore, I would like to discuss whether it is possible to > > >>> solve > > >>>>>>>> this > > >>>>>>>>>> problem > > >>>>>>>>>>> by creating Flink's own Calcite repository. > > >>>>>>>>>>> > > >>>>>>>>>>> Currently, Flink depends on Caclite-1.26, FLIP-204[1] relies on > > >>>>>>>>>> Calcite-1.30, > > >>>>>>>>>>> and we recently want to support fully join-hints functionatity > > >>> in > > >>>>>>>>>> Flink-1.16, > > >>>>>>>>>>> which relies on Calcite-1.31 (maybe two or three months later > > >>> will be > > >>>>>>>>>> released). > > >>>>>>>>>>> In order to support some new features or fix some bugs, we need > > >>> to > > >>>>>>>>>> upgrade > > >>>>>>>>>>> the Calcite version, but every time we upgrade Calcite version > > >>>>>>>>>>> (especially upgrades > > >>>>>>>>>>> across multiple versions), the processing is very tough: I > > >>> remember > > >>>>>>>>>> clearly that > > >>>>>>>>>>> the Calcite upgrade from 1.22 to 1.26 took two weeks of > > >>> full-time to > > >>>>>>>>>> complete. > > >>>>>>>>>>> Currently, in order to fix some bugs while not upgrading the > > >>> Calcite > > >>>>>>>>>> version, > > >>>>>>>>>>> we copy the corresponding Calcite class directly into the Flink > > >>>>>>>> project > > >>>>>>>>>>> and then modify it accordingly.[2] This approach is rather > > >>> hacky and > > >>>>>>>>>>> hard for code maintenance and upgrades. > > >>>>>>>>>>> > > >>>>>>>>>>> So, I had an idea whether we could solve this problem by > > >>> maintaining a > > >>>>>>>>>>> Calcite repository > > >>>>>>>>>>> in the Flink community. This approach has been practiced within > > >>> my > > >>>>>>>>>>> company for many years. > > >>>>>>>>>>> There are similar practices in the industry. For example, > > >>> Apache > > >>>>>>>> Dill > > >>>>>>>>>>> also maintains > > >>>>>>>>>>> a separate Calcite repository[3]. > > >>>>>>>>>>> > > >>>>>>>>>>> The following is a brief analysis of the approach and the pros > > >>> and > > >>>>>>>>>>> cons of maintaining a separate repository. > > >>>>>>>>>>> > > >>>>>>>>>>> Approach: > > >>>>>>>>>>> 1. Where to put the code? https://github.com/flink-extended is > > >>> a good > > >>>>>>>>>> place. > > >>>>>>>>>>> 2. What extra code can be added to this repository? Only bug > > >>> fixes and > > >>>>>>>>>> features > > >>>>>>>>>>> that are already merged into Calcite can be cherry-picked to > > >>> this > > >>>>>>>>>> repository. > > >>>>>>>>>>> We also should try to push bug fixes to the Calcite community. > > >>>>>>>>>>> Btw, the copied Calcite class in the Flink project can be > > >>> removed. > > >>>>>>>>>>> 3. How to upgrade the Calcite version? Check out the target > > >>> Calcite > > >>>>>>>>>>> release branch > > >>>>>>>>>>> and rebase our bug fix code. (As we upgrade, we will maintain > > >>> fewer > > >>>>>>>>>>> and fewer older bug > > >>>>>>>>>>> fixes code.) And then, verify all Calcte's tests and Flink's > > >>> tests in > > >>>>>>>>>>> the developer's local > > >>>>>>>>>>> environment. If all tests are OK, release the Calcite > > >>> branch, or fix > > >>>>>>>>>>> it in the branch and re-test. > > >>>>>>>>>>> After the branch is released, then the version of Calcite > > in > > >>> Flink > > >>>>>>>>>>> can be upgraded. For example: > > >>>>>>>>>>> checkout calcite-1.26.0-flink-v1-SNAPSHOT branch from > > >>>>>>>> calcite-1.26.0, > > >>>>>>>>>>> move all the copied > > >>>>>>>>>>> Calcite code in Flink to the branch, and pick all the hint > > >>> related > > >>>>>>>>>>> changes from Calcite-1.31 to > > >>>>>>>>>>> the branch. Then we can change the Calcite version in Flink > > >>> to > > >>>>>>>>>>> calcite-1.26.0-flink-v1-SNAPSHOT, > > >>>>>>>>>>> and verify all tests in the locale. Release > > >>> calcite-1.26.0-flink-v1 > > >>>>>>>>>>> after all tests are successful. > > >>>>>>>>>>> At last upgrade the calcite version to > > >>>>>>>>>>> calcite-1.26.0-flink-v10-flink-v1, and open a PR. > > >>>>>>>>>>> 4. Who will maintain it? The maintenance workload is minimal, > > >>> but the > > >>>>>>>>>>> upgrade work is > > >>>>>>>>>>> laborious (actually, it's similar to before). I can > > maintain > > >>> it in > > >>>>>>>>>>> the early stage and standardise the processing. > > >>>>>>>>>>> > > >>>>>>>>>>> Pros. > > >>>>>>>>>>> 1. The release of Flink is decoupled from the release of > > >>> Calcite, > > >>>>>>>>>>> making feature development and bug fix quicker > > >>>>>>>>>>> 2. Reduce the hassle of unnecessary calcite upgrades > > >>>>>>>>>>> 3. No hacking in Flink to maintain the Calcite copied code > > >>>>>>>>>>> > > >>>>>>>>>>> cons. > > >>>>>>>>>>> 1. Need to maintain an additional Calcite repository > > >>>>>>>>>>> 2. The Upgrades are a little more complicated than before > > >>>>>>>>>>> > > >>>>>>>>>>> Any feedback is very welcome! > > >>>>>>>>>>> > > >>>>>>>>>>> > > >>>>>>>>>>> [1] > > >>> > > https://cwiki.apache.org/confluence/display/FLINK/FLIP-204%3A+Introduce+Hash+Lookup+Join > > >>>>>>>>>>> [2] > > >>> > > https://github.com/apache/flink/tree/master/flink-table/flink-table-planner/src/main/java/org/apache/calcite > > >>>>>>>>>>> [3] https://github.com/apache/drill/blob/master/pom.xml#L64 > > >>>>>>>>>>> > > >>>>>>>>>>> Best, > > >>>>>>>>>>> Godfrey > > >>>>>>>>>> > > > >
