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> 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 > > >
