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From Nikolay Izhikov <nizhi...@apache.org>
Subject Re: New SQL execution engine
Date Fri, 27 Sep 2019 16:26:14 GMT
Hello, Denis.

Thanks for the clarifications.

Sounds good for me.
All I try to say in this thread: 
Guys, please, let's take a step back and write down requirements(what we want to get with
SQL engine).
Which features and use-cases are primary for us.

I'm sure you have done it, already during your research.

Please, share it with the community.

I'm pretty sure we would back to this document again and again during migration.
So good written design is worth it.

В Пт, 27/09/2019 в 09:10 -0700, Denis Magda пишет:
> Ignite mates, let me try to move the discussion in a constructive way. It
> looks like we set a wrong context from the very beginning.
> 
> Before proposing this idea to the community, some of us were
> discussing/researching the topic in different groups (the one need to think
> it through first before even suggesting to consider changes of this
> magnitude). The day has come to share this idea with the whole community
> and outline the next actions. But (!) nobody is 100% sure that that's the
> right decision. Thus, this will be an *experiment*, some of our community
> members will be developing a *prototype* and only based on the prototype
> outcomes we shall make a final decision. Igor, Roman, Ivan, Andrey, hope
> that nothing has changed and we're on the same page here.
> 
> Many technical and architectural reasons that justify this project have
> been shared but let me throw in my perspective. There is nothing wrong with
> H2, that was the right choice for that time.  Thanks to H2 and Ignite SQL
> APIs, our project is used across hundreds of deployments who are
> accelerating relational databases or use Ignite as a system of records.
> However, these days many more companies are migrating to *distributed*
> databases that speak SQL. For instance, if a couple of years ago 1 out of
> 10 use cases needed support for multi-joins queries or queries with
> subselects or efficient memory usage then today there are 5 out of 10 use
> cases of this kind; in the foreseeable future, it will be a 10 out of 10.
> So, the evolution is in progress -- the relational world goes distributed,
> it became exhaustive for both Ignite SQL maintainers and experts who help
> to tune it for production usage to keep pace with the evolution mostly due
> to the H2-dependency. Thus, Ignite SQL has to evolve and has to be ready to
> face the future reality.
> 
> Luckily, we don't need to rush and don't have the right to rush because
> hundreds existing users have already trusted their production environments
> to Ignite SQL and we need to roll out changes with such a big impact
> carefully. So, I'm excited that Roman, Igor, Ivan, Andrey stepped in and
> agreed to be the first contributors who will be *experimenting* with the
> new SQL engine. Let's support them; let's connect them with Apache Calcite
> community and see how this story evolves.  Folks, please keep the community
> aware of the progress, let us know when help is needed, some of us will be
> ready to support with development once you create a solid foundation for
> the prototype.
> 
> -
> Denis
> 
> 
> On Fri, Sep 27, 2019 at 1:45 AM Igor Seliverstov <gvvinblade@apache.org>
> wrote:
> 
> > Hi Igniters!
> > 
> > As you might know currently we have many open issues relating to current
> > H2 based engine and its execution flow.
> > 
> > Some of them are critical (like impossibility to execute particular
> > queries), some of them are majors (like impossibility to execute particular
> > queries without pre-preparation your data to have a collocation) and many
> > minors.
> > 
> > Most of the issues cannot be solved without whole engine redesign.
> > 
> > So, here the proposal:
> > https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=130028084
> > 
> > I'll appreciate if you share your thoughts on top of that.
> > 
> > Regards,
> > Igor
> > 

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