Hello, I don't see any risk committing this right now in master. It will only affect the new Hive release when and if it ever goes out. Till then we have plenty of time to fix shading problems and help other projects migrate to the "recommended" way to use Hive.
Moreover, I don't know many projects relying on this kind of "double" (core vs. fat) publication of dependencies. For Hive, it creates additional maintenance cost and for its users confusion on what they should use. If for whatever reason, another project does not want to include everything coming in the fat jar, maven provides ways to do it. I wouldn't recommend going down this path but there are alternatives. Best, Stamatis On Wed, Nov 17, 2021 at 8:15 PM Zoltan Haindrich <k...@rxd.hu> wrote: > > > On 11/17/21 7:46 PM, Chao Sun wrote: > >> We have a working hive-exec jar > > > > I'm not sure about this. The issue comes when the fat hive-exec jar > shades > > some jars but doesn't relocate them. In this case there is no way for the > > downstream projects to resolve the conflict. > > Exactly - I think those should be hammered out for good; fix the > shading/relocation! > > > > > On the Spark side IIUC we had issues with Apache Commons as well as ORC > > (see HIVE-25317 for an effort on this), and there could be more. Spark is > > using Hive 2.3 though but the same applies for master/4.0 if dependency > > versions differ between Hive and the downstream projects. > > This change is only about master - it won't change Hive 2.3. HIVE-25317 > was for branch-2 as well. > I've seen a few places wierd stuff because they were not able to use the > hive-exec jar as-is. > Folks in the Impala project for example went in a direction to > re-shade/re-filter the hive-exec jar and relocate some stuff in it - most > likely because it conflicted with > their stuff. > > https://github.com/apache/impala/blob/master/java/shaded-deps/hive-exec/pom.xml > Taking a quick look at https://github.com/apache/spark/pull/33989/files > it seems like you've also done something similar....but instead of using > the base artifact; you have > created a new shader. > I don't think this better than having an artifact which is simply works > out-of-the-box. > > > cheers, > Zoltan > > > > > On Wed, Nov 17, 2021 at 10:35 AM Zoltan Haindrich <k...@rxd.hu> wrote: > > > >> On 11/17/21 7:07 PM, Daniel Fritsi wrote: > >>> For Oozie we've decided to use fat Jar downstream (Cloudera) as there > we > >> have processes to ensure 3rd-party library versions are kept in sync. > >>> > >>> Since we don't have such a process in Apache, there we'll continue to > >> use the core Jar. > >> > >> It might be possible to evade some problems by using a 3rd party lib > >> syncer - but if we've done a good job shading this stuff; it should not > >> cause any trouble even in case > >> other 3rd party stuff is present....but in any case to check things out > >> you will need a Hive release in some form > >> > >> cheers, > >> Zoltan > >> > >>> > >>> Dan > >>> > >>> On 2021. 11. 17. 18:50, Chao Sun wrote: > >>>>> the idea is to fix the issues they bump into - because people who > load > >>>> the jdbc driver may also see those issues. > >>>> > >>>> I don’t get what you mean here, could you elaborate a bit more? > >>>> > >>>> IMO it's a bit premature to do this without a working hive-exec jar > for > >>>> downstream projects like Spark/Trino/Presto. At the current state > there > >> is > >>>> no way to upgrade these projects to use the fat hive-exec jar. > >>>> > >>>> > >>>> > >>>> On Wed, Nov 17, 2021 at 5:47 AM Zoltan Haindrich<k...@rxd.hu> wrote: > >>>> > >>>>> Hey all, > >>>>> > >>>>> I wanted to get back to this - but had other things going on. > >>>>> > >>>>> Chao> it is still being used today by some other popular projects > >>>>> the idea is to fix the issues they bump into - because people who > load > >> the > >>>>> jdbc driver may also see those issues. > >>>>> > >>>>> Edward> [...] You all must like enjoy shading jars. > >>>>> I totally agree that they may use a shell action as well. > >>>>> I wonder how do you propose to solve issues related to clients using > a > >>>>> different version of the guava library? > >>>>> > >>>>> The changes which will remove the core artifact stuff is ready: > >>>>> https://github.com/apache/hive/pull/2648 > >>>>> > >>>>> cheers, > >>>>> Zoltan > >>>>> > >>>>> On 9/21/21 8:23 PM, Edward Capriolo wrote: > >>>>>> recommendation from the Hive team is to use the hive-exec.jar > >> artifact. > >>>>>> > >>>>>> You know about 10 years ago. I mentioned that oozie should just use > >>>>>> hive-service or hive jdbc. After a big fight where folks kept > >> bringing up > >>>>>> concurrency bugs in hive-server-1 my prs were rejected (even though > >> hive > >>>>>> server2 would not have these bugs). I still cannot fathom why > someone > >>>>> using > >>>>>> oozie would want a fat jar of hive (as opposed to hive server or > >>>>> hivejdbc) > >>>>>> . If I had to do that, i would just use shell action..... You all > must > >>>>> like > >>>>>> enjoy shading jars. > >>>>>> > >>>>>> Edward > >>>>>> > >>>>>> On Thu, Sep 16, 2021 at 2:30 PM Chao Sun<sunc...@apache.org> > wrote: > >>>>>> > >>>>>>> I'm not sure whether it is a good idea to remove `hive-exec-core` > >>>>>>> completely - it is still being used today by some other popular > >> projects > >>>>>>> including Spark and Trino/Presto. By sticking to `hive-exec-core` > it > >>>>> gives > >>>>>>> more flexibility to the other projects to shade & relocate those > >> classes > >>>>>>> according to their need, without waiting for new Hive releases. > Hive > >>>>> also > >>>>>>> needs to make sure it relocate everything properly. Otherwise, if > >> some > >>>>>>> classes are shaded & included in `hive-exec` but not relocated, > there > >>>>> is no > >>>>>>> way for the other projects to exclude them and avoid potential > >>>>> conflicts. > >>>>>>> Chao > >>>>>>> > >>>>>>> On Thu, Sep 16, 2021 at 8:03 AM Zoltan Haindrich<k...@rxd.hu> > >> wrote: > >>>>>>> > >>>>>>>> Hey > >>>>>>>> > >>>>>>>> On 9/6/21 12:48 PM, Stamatis Zampetakis wrote: > >>>>>>>>> Indeed this may lead to binary incompatibility problems as the > one > >> you > >>>>>>>>> mentioned. If I understood correctly the problem you cite comes > up > >> if > >>>>>>>>> library B in this case is not relocated. If Hive systematically > >>>>>>> relocates > >>>>>>>>> shaded deps do you think there will still be binary > incompatibility > >>>>>>>> issues? > >>>>>>>>> If the relocating solution works, I would personally prefer going > >> down > >>>>>>>> this > >>>>>>>>> path instead of introducing an entirely new module just for the > >> sake > >>>>> of > >>>>>>>>> dependency management. Most of the time when there are problems > >> with > >>>>>>>>> shading the answer comes from relocating the problematic > >> dependencies > >>>>>>> and > >>>>>>>>> people are more or less accustomed with this route. > >>>>>>>> I totally agree with you Stamatis - with the addition that we > should > >>>>> work > >>>>>>>> together with the owners of other projects to help them use the > >> correct > >>>>>>>> artifact to gain access to > >>>>>>>> Hive's internal parts. > >>>>>>>> I've opened HIVE-25531 to remove the core classified artifact - > and > >>>>>>> ensure > >>>>>>>> that we will be uncovering and fixing future issues with the > >> hive-exec > >>>>>>>> artifact. > >>>>>>>> > >>>>>>>> cheers, > >>>>>>>> Zoltan > >>>>>>>> > >>>>>>>> > >>>>>>>>> Best, > >>>>>>>>> Stamatis > >>>>>>>>> > >>>>>>>>> On Mon, Aug 30, 2021 at 9:49 PM Daniel Fritsi > >>>>>>>> <fdan...@cloudera.com.invalid> > >>>>>>>>> wrote: > >>>>>>>>> > >>>>>>>>>> Dear Hive developers, > >>>>>>>>>> > >>>>>>>>>> I am Dan from the Oozie team and I would like to bring up the > >>>>>>>>>> hive-exec.jar vs. hive-exec-core.jar topic. > >>>>>>>>>> The reason for that is because as far as we understand the > >> official > >>>>>>>>>> recommendation from the Hive team is to use the hive-exec.jar > >>>>>>> artifact. > >>>>>>>>>> However in Oozie that can end-up in a binary incompatibility. > >>>>>>>>>> > >>>>>>>>>> The reason for that is: > >>>>>>>>>> > >>>>>>>>>> * Let's say library A is included in the fat Jar. > >>>>>>>>>> > >>>>>>>>>> * And library B which is using library A is also included > in > >> the > >>>>>>> fat > >>>>>>>> Jar. > >>>>>>>>>> * Let's also say that library A's com.library.alib > package is > >>>>>>>>>> relocated to org.apache.hive.com.library.alib, > >>>>>>>>>> meaning the com.library.alib.SomeClass becomes > >>>>>>>>>> org.apache.hive.com.library.alib.SomeClass > >>>>>>>>>> > >>>>>>>>>> * So if B has a method like public void > >>>>>>>>>> someMethod(com.library.alib.SomeClass) then the > signature > >> of > >>>>> this > >>>>>>>>>> method will be changed to: > >>>>>>>>>> public void > >>>>>>> someMethod(org.apache.hive.com.library.alib.SomeClass) > >>>>>>>>>> * If Oozie is also using B directly meaning we'll have > b.jar > >> on > >>>>> our > >>>>>>>>>> classpath, but with the unchanged signature, > >>>>>>>>>> so when hive-exec tries to invoke someMethod then > >> depending on > >>>>>>>>>> whether b.jar coming from us will be loaded first or > >> hive-exec > >>>>>>>> will, > >>>>>>>>>> we can end-up with a NoSuchMethodError is hive-exec > tries > >> to > >>>>> pass > >>>>>>>> an > >>>>>>>>>> org.apache.hive.com.library.alib.SomeClass instance to > the > >>>>>>>>>> someMethod which was loaded from the original b.jar. > >>>>>>>>>> > >>>>>>>>>> Hence in Oozie a long time ago (OOZIE-2621 > >>>>>>>>>> <https://issues.apache.org/jira/browse/OOZIE-2621>) the > decision > >> was > >>>>>>>>>> made to use the hive-exec-core Jar. > >>>>>>>>>> > >>>>>>>>>> Now since the shading process actually removes those > dependencies > >>>>> from > >>>>>>>>>> the hive-exec pom which are included in the fat Jar, we manually > >> had > >>>>>>> to > >>>>>>>>>> add some dependencies to Oozie to compensate this. > >>>>>>>>>> However these dependencies are not used by Oozie directly and > with > >>>>> the > >>>>>>>>>> growing features of hive-exec we had to repeat the same process > >>>>>>>>>> over-and-over which is a bit unmaintainable. > >>>>>>>>>> > >>>>>>>>>> Today I'm writing to you to propose a long-term solution where > >>>>>>> basically > >>>>>>>>>> nothing would change in the generated hive artifacts, poms and > the > >>>>>>> same > >>>>>>>>>> time we wouldn't have to manually declare dependencies in Oozie > >> which > >>>>>>>>>> are not explicitly used by us. > >>>>>>>>>> > >>>>>>>>>> The solution: > >>>>>>>>>> > >>>>>>>>>> 1. We would create a new module named > hive-exec-dependencies > >> which > >>>>>>>>>> would be a pom-packaging module without any Java source > >> files. > >>>>>>>>>> 2. All the dependencies declared in hive-exec would be > moved > >> to > >>>>>>>>>> hive-exec-dependencies. > >>>>>>>>>> 3. We would make the hive-exec-dependencies module the > parent > >> of > >>>>>>>>>> hive-exec and with this hive-exec would still have > access > >> to > >>>>> the > >>>>>>>>>> same dependencies as before. > >>>>>>>>>> 4. The maven shade plugin would still strip the > dependencies > >> from > >>>>>>> the > >>>>>>>>>> generated hive-exec pom which are included in the fat > Jar. > >>>>>>>>>> 5. And with a small maven plugin we'd change hive-exec's > >> parent > >>>>> back > >>>>>>>>>> from hive-exec-dependencies to the root hive project in > the > >>>>>>>>>> generated hive-exec pom file. > >>>>>>>>>> > >>>>>>>>>> I have a change ready locally and it works as described above. > >>>>>>>>>> > >>>>>>>>>> With this on the Oozie side we could add a dependency on > >>>>>>>>>> hive-exec-dependencies and hence all the required libraries > which > >> are > >>>>>>>>>> included in the fat Jar would be pulled into Oozie. > >>>>>>>>>> The next time a new dependency would be added to > >>>>>>> hive-exec-dependencies, > >>>>>>>>>> the Oozie build would pull it in automatically without us having > >> to > >>>>>>>>>> explicitly declare it. > >>>>>>>>>> > >>>>>>>>>> Please let me know what you think. > >>>>>>>>>> > >>>>>>>>>> Best, > >>>>>>>>>> Dan > >>>>>>>>>> > >>> > >> > > >
