Hi Jacques, Julian, Austin and everyone else, Thank you very much for sharing all your experiences and providing really valuable input. I'll definitely relay this back to the original discussion thread in the Flink community. Part of bringing this information back to the Flink community is also because I feel like the only way that different OSS solutions can help each other forward is by communicating and collaborating. As Timo already mentioned, he'll try to help out. Let's try to get some more involved.
Side note: I also saw that this thread got some traction on Twitter [1] on the cost of forking. Best regards, Martijn [1] https://twitter.com/gunnarmorling/status/1539499415337111553?s=21&t=8fGk3PxScOx4FJPJWE5UeA Op wo 22 jun. 2022 om 09:29 schreef Timo Walther <twal...@apache.org>: > Hi everyone, > > This is a really great discussion. Thanks for starting it Martijn and > your input Jacques! I have been fighting against forking Calcite in > Flink for years already. Even when merging forks of Flink that > transitively forked Calcite, in the end we were able to resolve > conflicts / contribute blockers back into Calcite. And I strongly > believe that this is the better approach for long-term success for both > projects. > > I would like to get more involved in the Calcite community. I have been > implementing and managing Flink SQL based on Calcite since 2016. Thus, I > feel confident to say that I know the code base and some quirks in the > stack very well. > > Capacity-wise I will try to reserve some time for helping the Calcite > community. Happy to get some pointers where and how I can help. > > I will take a look at https://github.com/apache/calcite/pull/2606 this > week to get the ball rolling. As this is an important addition and > prepares for "customer SQL operators" in Flink SQL. > > Regards, > Timo > > On 21.06.22 22:18, Charles Givre wrote: > > As the PMC for Apache Drill, I'd echo everyone's comments here.... Don't > fork. Don't do it. > > > > Apache Drill forked Calcite several years ago which Calcite was on > version 1.20 or 1.21. While this meant that some bugs were easily fixed, > what it also meant that as our fork diverged from "regular" Calcite, it > became harder and harder to maintain. It also meant that we were chasing > bugs that had since been fixed. > > > > Drill is in the process of "de-forking" Calcite, meaning that we're > ditching our fork and re-integrating with standard Calcite. It has been A > TON of work and we have contributed (and will continue to contribute) bug > fixes and PRs to Calcite. In the long run, I think this will be beneficial > for both communities. > > > > Best, > > -- C > > > > > >> On Jun 21, 2022, at 1:57 PM, Julian Hyde <jhyde.apa...@gmail.com> > wrote: > >> > >> Please don’t fork Calcite. > >> > >> Calcite suffers from the tragedy of the commons. Unlike many open > source data projects, there is no commercial project that directly maps to > Calcite (even though Calcite is an essential part of many projects). As a > result no engineers work full-time on Calcite. > >> > >> It takes more than pull requests to keep a project going. We need > reviewers, people to work on releases, people to fix bugs (such as security > bugs) that are important to everyone but urgent to no one. > >> > >> We have plenty of committers in Calcite, and add several more per year. > We rely on those committers taking on their share of the housework, but the > burden falls on too few people. > >> > >> Engineering managers need to start paying a little more for the “free > lunch” that they enjoy when Calcite “just works” in their project. Sadly, > most engineering managers are not subscribed to this list. > >> > >> Julian > >> > >> > >>> On Jun 21, 2022, at 9:49 AM, Jacques Nadeau <jacq...@apache.org> > wrote: > >>> > >>> Martijn, thanks for sharing that thread in the Flink community. > >>> > >>> I'm someone who has forked Calcite twice: once in Apache Drill and > again in > >>> Dremio. In both cases, it was all about trading short term benefits > against > >>> long term costs. In both cases, I think the net amount of work was > probably > >>> 5x as much as what it would have been if we had just done a better job > >>> engaging the community. If I were to state the curve of behavior over > six > >>> years, I'd guess that in both cases the numbers of effort looked like > this: > >>> > >>> estimated effort doing high intensity integration with calcite (years > 1-6) > >>> fork: 1, 5, 10, 50, 100, 200, total = 366 > >>> non-fork: 10, 10, 10, 10, 10, total = 50 > >>> > >>> So yes, the first couple years you're ahead. But you pay a massive > >>> technical debt premium long term. Early in a project (Drill) or > company's > >>> life (Dremio), it can make sense to sacrifice long term for short term > but > >>> it's important people do it with their eyes open. > >>> > >>> The reason that this pain is so high is that as your codebases > diverge, you > >>> start having to do everything the Calcite community does by yourself. > >>> Backports become harder and things that you need (e.g. new sql syntax, > etc) > >>> have to be reimplemented (even if someone else already implemented > them in > >>> some post-fork Calcite version. Ultimately, at some point you realize > that > >>> your path is untenable and you unfork. This becomes the biggest > expense of > >>> them all and I believe both of those teams are still trying to > un-fork. The > >>> additional thing that becomes an even bigger problem is your absence > from > >>> the Calcite community means that people may take the project or APIs in > >>> ways that are in direct conflict to how you use the library. Since > you're > >>> not active in the project, you fail to provide a counterpoint and then > >>> you're basically just in a miserable place. The Hive project did this > best > >>> by ensuring that releases of Calcite were also run pre-release against > Hive > >>> to make sure no major regressions occurred. By being in the community > and > >>> active, this is the best state from my pov. (It makes your project > better > >>> and Calcite better.) > >>> > >>> Two last notes: > >>> - I'm not sure the rocks fork is comparable to forking Calcite. The api > >>> surface area and community models are very different. > >>> - This is all based on a high intensity integration (using rules + > planner > >>> or sql + rules + planner). Calcite is frustratingly monolithic and if > >>> someone was only going to use a small component, my opinion would > likely be > >>> very different. > >>> > >>> I'd send this to the Flink list but I'm not subscribed. It'd be great > if > >>> you shared it with the people over there if you think they'd find it > useful. > >>> > >>> > >>> > >>> On Tue, Jun 21, 2022 at 12:31 AM Martijn Visser < > martijnvis...@apache.org> > >>> wrote: > >>> > >>>> Thanks Julian and Austin! > >>>> > >>>> Any reply to kick-off some sort of discussion is worthwhile :D > >>>> I definitely know the feeling of having more PRs open then you would > like, > >>>> looking at https://github.com/apache/flink/pulls :) > >>>> > >>>> There have been discussions in the Flink community about forking > Calcite > >>>> [1]. My personal preference at the moment is to see if we can create a > >>>> better collaboration and community. I believe that we can find people > from > >>>> the Flink community who can open / help reviewing Calcite PRs that are > >>>> interesting for the Flink community. The question is if that will > also help > >>>> short term since in the end it still requires a Calcite maintainer to > >>>> review/merge. > >>>> > >>>> Best regards, > >>>> > >>>> Martijn > >>>> > >>>> [1] https://lists.apache.org/thread/1oqydpsm4mc55bkk440gx9lr9gf2rvf4 > >>>> > >>>> > >>>> Op ma 20 jun. 2022 om 23:51 schreef Austin Bennett < > >>>> whatwouldausti...@gmail.com>: > >>>> > >>>>> From the peanut gallery :-) --> > >>>>> > >>>>> Wow; yes, lots of open PRs. https://github.com/apache/calcite/pulls > >>>>> > >>>>> How can individuals from the Flink [sub-]community, and/or more > general > >>>>> calcite community help lighten this load? Is there much weight > given to > >>>>> reviews from non-committers; how to increase the # of people capable > of > >>>>> providing worthwhile reviews [ that are recognized as such ]? > >>>>> > >>>>> > >>>>> > >>>>> On Mon, Jun 20, 2022 at 11:47 AM Julian Hyde <jhyde.apa...@gmail.com > > > >>>>> wrote: > >>>>> > >>>>>> Martijn, > >>>>>> > >>>>>> Since you requested a reply, I am replying. To answer your > question, I > >>>>>> don’t know of a way to move this topic forward. We have more PRs > than > >>>>>> people to review them. > >>>>>> > >>>>>> Julian > >>>>>> > >>>>>> > >>>>>>> On Jun 19, 2022, at 11:58 PM, Martijn Visser < > >>>> martijnvis...@apache.org > >>>>>> > >>>>>> wrote: > >>>>>>> > >>>>>>> Hi everyone, > >>>>>>> > >>>>>>> I just wanted to reach out to the Calcite community once more on > this > >>>>>> topic > >>>>>>> since no reply was received. Would be great if someone could get > back > >>>>> to > >>>>>> us. > >>>>>>> > >>>>>>> Best regards, > >>>>>>> > >>>>>>> Martijn > >>>>>>> > >>>>>>> Op wo 8 jun. 2022 om 11:24 schreef Martijn Visser < > >>>>>> martijnvis...@apache.org > >>>>>>>> : > >>>>>>> > >>>>>>>> Hi everyone, > >>>>>>>> > >>>>>>>> I would like to follow-up on this email that was sent by Jing. So > >>>> far, > >>>>>> no > >>>>>>>> progress has been made, despite reaching out to the mailing list, > >>>> the > >>>>>>>> original Jira ticket and reaching out to people directly. Is > there a > >>>>> way > >>>>>>>> that we can move this PR/topic forward? > >>>>>>>> > >>>>>>>> For context, in Apache Flink we're currently heavily using > Calcite. > >>>>>>>> However, we are now at the stage where Calcite is actually holding > >>>> us > >>>>>> back. > >>>>>>>> It would be great if we can find a way to strengthen our bond and > >>>> move > >>>>>> both > >>>>>>>> Calcite and Flink forward. > >>>>>>>> > >>>>>>>> Looking forward to your thoughts, > >>>>>>>> > >>>>>>>> Martijn > >>>>>>>> > >>>>>>>> On 2022/01/26 07:05:37 Jing Zhang wrote: > >>>>>>>>> Hi community, > >>>>>>>>> My apologies for interrupting. > >>>>>>>>> Anyone could help to review the pr > >>>>>>>>> https://github.com/apache/calcite/pull/2606? > >>>>>>>>> Thanks a lot. > >>>>>>>>> > >>>>>>>>> CALCITE-4865 is the first sub-task of CALCITE-4864. This Jira > aims > >>>> to > >>>>>>>>> extend existing Table function in order to support Polymorphic > >>>> Table > >>>>>>>>> Function which is introduced as the part of ANSI SQL 2016. > >>>>>>>>> > >>>>>>>>> The brief change logs of the PR are: > >>>>>>>>> - Update `Parser.jj` to support partition by clause and order by > >>>>>> clause > >>>>>>>>> for input table with set semantics of PTF > >>>>>>>>> - Introduce `TableCharacteristics` which contains three > >>>>>> characteristics > >>>>>>>>> of input table of table function > >>>>>>>>> - Update `SqlTableFunction` to add a method > >>>> `tableCharacteristics`, > >>>>>>>> the > >>>>>>>>> method returns the table characteristics for the ordinal-th > >>>> argument > >>>>> to > >>>>>>>>> this table function. Default return value is Optional.empty which > >>>>> means > >>>>>>>> the > >>>>>>>>> ordinal-th argument is not table. > >>>>>>>>> - Introduce `SqlSetSemanticsTable` which represents input table > >>>> with > >>>>>>>> set > >>>>>>>>> semantics of Table Function, its `SqlKind` is > `SET_SEMANTICS_TABLE` > >>>>>>>>> - Updates `SqlValidatorImpl` to validate only set semantic table > >>>> of > >>>>>>>> Table > >>>>>>>>> Function could have partition by and order by clause > >>>>>>>>> - Update `SqlToRelConverter#substituteSubQuery` to parse subQuery > >>>>>> which > >>>>>>>>> represents set semantics table. > >>>>>>>>> > >>>>>>>>> PR: https://github.com/apache/calcite/pull/2606 > >>>>>>>>> JIRA: https://issues.apache.org/jira/browse/CALCITE-4865 > >>>>>>>>> Parent JARA: https://issues.apache.org/jira/browse/CALCITE-4864 > >>>>>>>>> > >>>>>>>>> Best, > >>>>>>>>> Jing Zhang > >>>>>>>>> > >>>>>>>> > >>>>>> > >>>>>> > >>>>> > >>>> > >> > > > >
