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From Nikolay Izhikov <nizhi...@apache.org>
Subject Re: New SQL execution engine
Date Fri, 27 Sep 2019 14:24:34 GMT
Thanks, Andrey! 

Will take a loo, shortly.

В Пт, 27/09/2019 в 17:19 +0300, Andrey Mashenkov пишет:
> Issues can't be resolved without changes in H2.
> Hope, this will be enough.
> 
> https://issues.apache.org/jira/browse/IGNITE-10598
> https://issues.apache.org/jira/browse/IGNITE-11473
> https://issues.apache.org/jira/browse/IGNITE-11444
> https://issues.apache.org/jira/browse/IGNITE-5289
> https://issues.apache.org/jira/browse/IGNITE-10855
> https://issues.apache.org/jira/browse/IGNITE-11341
> https://issues.apache.org/jira/browse/IGNITE-7526
> https://issues.apache.org/jira/browse/IGNITE-9480
> https://issues.apache.org/jira/browse/IGNITE-9616
> https://issues.apache.org/jira/browse/IGNITE-11891
> https://issues.apache.org/jira/browse/IGNITE-6202
> https://issues.apache.org/jira/browse/IGNITE-11448
> https://issues.apache.org/jira/browse/IGNITE-3911
> 
> 
> On Fri, Sep 27, 2019 at 4:34 PM Nikolay Izhikov <nizhikov@apache.org> wrote:
> 
> > Roman.
> > 
> > > Nikolay, Maxim, I understand that our arguments may not be as obvious
> > > for you as it obvious for SQL team. So, please arrange your questions in
> > > a more constructive way.
> > 
> > What is SQL team?
> > I only know Ignite community :)
> > 
> > Please, share you knowledge in IEP.
> > I want to join to the process of engine *selection*.
> > It should start with the requirements to such engine.
> > Can you write it in IEP, please?
> > 
> > My point is very simple:
> > 
> > 1. We made the wrong decision with H2
> > 2. We should make a well-thought decision about the new engine.
> > 
> > > How many tickets would satisfy you?
> > 
> > You write about "issueS" with the H2.
> > All I see is one open ticket.
> > IEP doesn't provide enough information.
> > So it's not about the number of tickets, it's about
> > 
> > > These two points (single map-reduce execution and inflexible optimizer)
> > > are the main problems with the current engine.
> > 
> > We may come to the point when Calcite(or any other engine) brings us third
> > and other "main problems".
> > This is how it happens with H2.
> > 
> > Let's start from what we want to get with the engine and move forward from
> > this base.
> > What do you think?
> > 
> > 
> > 
> > В Пт, 27/09/2019 в 16:15 +0300, Roman Kondakov пишет:
> > > Maxim, Nikolay,
> > > 
> > > I've listed two issues which show the ideological flaws of the current
> > > engine.
> > > 
> > > 1. IGNITE-11448 - Open. This ticket describes the impossibility of
> > > executing queries which can not be fit in the hardcoded one pass
> > > map-reduce paradigm.
> > > 
> > > 2. IGNITE-6085 - Closed (won't fix) - This ticket describes the second
> > > major problem with the current engine: H2 query optimizer is very
> > > primitive and can not perform many useful optimizations.
> > > 
> > > These two points (single map-reduce execution and inflexible optimizer)
> > > are the main problems with the current engine. It means that our engine
> > > is currently  suitable for execution only a very limited subset of the
> > > typical SQL queries. For example it can not even run most of the TPC-H
> > > benchmark queries because they don't fit to the simple map-reduce
> > 
> > paradigm.
> > > 
> > > > All I see is links to two tickets:
> > > 
> > > How many tickets would satisfy you? I named two. And it looks like it is
> > > not enough from your point of view. Ok, so how many is enough? The set
> > > of problems caused by listed above tickets is infinite, therefore I can
> > > not create a ticket for each of them.
> > > > Tech details also should be added.
> > > 
> > > Tech details are in the tickets.
> > > 
> > > > We can't discuss such a huge change as an execution engine replacement
> > 
> > with descrition like:
> > > > "No data co-location control, i.e. arbitrary data can be returned
> > 
> > silently" or
> > > > "Low control on how query executes internally, as a result we have
> > 
> > limited possibility to implement improvements/fixes."
> > > 
> > > Why not? Don't you understand these problems? Or you don't think this is
> > > a problem?
> > > 
> > > > Let's make these descriptions more specific.
> > > 
> > > What do you mean by "more specific"? What is the criteria of the
> > > specific description?
> > > 
> > > 
> > > 
> > > Nikolay, Maxim, I understand that our arguments may not be as obvious
> > > for you as it obvious for SQL team. So, please arrange your questions in
> > > a more constructive way.
> > > 
> > > Thank you!
> 
> 

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