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From Julian Hyde <>
Subject Re: [DISCUSS] Move Avatica to a sub-project?
Date Tue, 02 Feb 2016 19:16:32 GMT
Calcite’s parent pom is in the root directory of the repo, and it makes sense to keep it

So I think Avatica would remain in the avatica directory, avatica/pom.xml would become a parent
POM, we’d move avatica-server to become avatica/server and we’d move avatica/src to avatica/core/src.
Then we’d add NOTICE, LICENSE, README, site under avatica.

And we’d remove 


from the calcite parent pom.xml, and make Avatica’s pom.xml inherit directly from the Apache
parent pom.


> On Feb 2, 2016, at 11:05 AM, Josh Elser <> wrote:
> Any thoughts on how the layout/versioning should work? We could move Avatica into a top-level
directory and have it separated from the "calcite" repository. So, to build Avatica, you'd
have to `cd avatica && mvn <foo>`. The calcite modules would pull from your
local repo or the configured remote repo(s). This would make cross-cutting changes a bit harder
to verify, but it's probably a necessary evil for the eventual separation.
> I don't think a separate Git repo is required now, but those are pretty cheap as far
as INFRA goes (to my understanding) which is why I had suggested it originally.
> When I get a moment, I'll make some uber/epic JIRA issue to track the stuff to do which
we can pile on.
> Thanks for your input, Julian and Ted.
> Julian Hyde wrote:
>> My feeling is that Avatica ultimately needs to be a TLP, with its own governance.
Calcite is, in a sense, incubating it until it is ready. My concern is that if we "release
the pressure” we’ll lose the impetus to make it a TLP and get stuck half-way.
>> That said, Avatica does not have enough activity to be a TLP right now. So let’s
start the separation, so that Avatica will be perceived as more independent.
>> I think Solr is a good example to follow. It is a sub-project of Lucene but is branded
separately; for instance, it has its own site: but the projects
share a dev list. I like the idea of Avatica having its own site, say
>> We will need to create a new site directory (in Jekyll layout), a new Avatica parent
POM, and a new However, I am neutral on whether the git repos need to be separated
at this point.
>> Julian
>>> On Jan 30, 2016, at 8:47 PM, Ted Dunning<>  wrote:
>>> I would suggest just having a separate release artifact for a time before
>>> spinning out a separate TLP.  Separate TLP is a pain in the *.
>>> Speaking from experience ages ago with Mahout, having a separate artifact
>>> that had a different audience than the main project worked just fine.
>>> On Fri, Jan 29, 2016 at 10:29 PM, Josh Elser<>  wrote:
>>>> Yeah, sub project is probably not the right terminology in retrospect. I'm
>>>> not sure what the word for it is: I was suggesting just another repository
>>>> and everything else stays the same. Glad you knew what I meant to say.
>>>> Maybe the question right now is: what would be gained by having a separate
>>>> PMC (ignoring community building type questions)? I can envision Avatica
>>>> eventually being mature enough to be a TLP, but would it help to start
>>>> splitting things now while trying to grow involvement (and solve the
>>>> community size issues)? Is the middle step worth the effort?
>>>> On Jan 29, 2016 8:27 PM, "Julian Hyde"<>  wrote:
>>>>> Allow me to play devil’s advocate and to look at some other options.
>>>>> What would be the practical difference between a sub-project and what
>>>>> have now?
>>>>> * The code split into different repositories
>>>>> * De-coupled release schedule
>>>>> * More distinct web site
>>>>> * But still the same namespace, org.apache.calcite
>>>>> By the way, I don’t think what you are proposing is a sub-project in
>>>>> Apache sense. (For example, Apache Derby is a sub-project of Apache DB.
>>>>> Derby’s PMC votes on releases, but DB’s PMC reports to the Apache
>>>> Board.) I
>>>>> gather that the Board is apparently no longer very fond of subprojects.
>>>>> What you are proposing, I think, would be a module of Calcite (or two
>>>>> avatica and avatica-server) whose release schedule is decoupled from
>>>>> main project’s release schedule.
>>>>> And let’s consider the other alternative: splitting Avatica out as
>>>>> top-level project (as ORC recently did from Hive). If Avatica became
>>>>> top-level project would naturally have its own repo, release schedule,
>>>> and
>>>>> could have its own web site and name space, org.apache.avatica. It would
>>>>> also have its own governance, i.e. a PMC that reports to the Board.
>>>>> It seems to me that Avatica, the software, makes more sense as a
>>>> top-level
>>>>> project. Does it make sense for Avatica, the community? I think so. You
>>>> are
>>>>> using Avatica for Phoenix independent of Calcite, and others are doing
>>>>> similar things. The only place we fall short is our number of active
>>>>> members. We need 3 active PMC members to make a release, and we basically
>>>>> have 2 right now (you and me).
>>>>> If we agree that a TLP is the best option in terms of governance and
>>>>> perception then we could make a push to recruit more Avatica committers
>>>> and
>>>>> PMC members.
>>>>> Julian
>>>>>> On Jan 29, 2016, at 12:35 PM, Josh Elser<>
>>>>>> Hi all,
>>>>>> I remember the question about spinning out Avatica was brought up
>>>> around
>>>>> the time Calcite graduation to TLP was happening.
>>>>>> Back then, I think Avatica was too early to really benefit from this
>>>>> distinction. Lately, I keep finding myself thinking that it might be
>>>> time.
>>>>> Of note, features/improvements that have happened since:
>>>>>> * Wire compatibility across releases (protobuf provides the
>>>>> building-blocks)
>>>>>> * Much better docs
>>>>>> * Steady increase in custom Avatica clients (people creating their
>>>>> client) [1] is the best OSS example I've come across
>>>>>> * Insight into the Avatica server w/o hacking the code: Logging and
>>>>> metrics (still WIP, but hopefully landing soon)
>>>>>> In other words, we've gotten much better at defining what is Avatica
>>>> and
>>>>> how to use it, with an emphasis in stability across releases. This is
>>>>> because a split from calcite "core" would require a very firm statement
>>>> of
>>>>> compatibility as Avatica changes would not be directly noticed to break
>>>>> "core" (as they would now in the same repo).
>>>>>> What I think makes sense is to spin Avatica into its own repository,
>>>>> still under the Calcite PMC umbrella. In other words, the Calcite PMC
>>>> would
>>>>> be responsible for both "Calcite" releases and "Avatica" releases, and
>>>>> releases of the one don't require a release of the other (although they
>>>> may
>>>>> continue to coincide). I don't believe their is significant interest
>>>>> justify spinning off Avatica into its own project (w/ governance), thus
>>>> the
>>>>> "sub-project" works well.
>>>>>> What do others think? Assuming we have release automation down,
>>>>> hopefully the doubled release work would not be a big concern. What have
>>>> I
>>>>> overlooked?
>>>>>> - Josh
>>>>>> [1]

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