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Re: [DISCUSS] Problem with 'assert' ignored in production, leading to inconsistent query results


Il giorno ven 21 set 2018 alle ore 20:03 Enrico Olivelli
<eolivelli@xxxxxxxxx> ha scritto:
>
>
>
> Il ven 21 set 2018, 19:45 Julian Hyde <jhyde@xxxxxxxxxx> ha scritto:
>>
>> Well, maybe we can.
>>
>> But look at the premise of the question: "Problem with 'assert'
>> ignored in production, leading to inconsistent query results". The
>> problem is not with the assert.
>
>
> Yes actually the bug is not clear.
>
> We have a merge join with 2 unsorted inputs. I don't know if the problem is in the planner (why it had choosen a merge join and not a simple joon ) or in the translation from planner output to actual plan
>
> I will be back with news next week.
> But I will start a new thread.
>
> Thank you for you comments and suggestions.
> I will evaluate if removing the assert with introduce too much cost (comparing large strings for instance)


This is the a patch, the assertion is an "integer < 0" check so it is
very cheap in Java, I think it is worth
https://issues.apache.org/jira/browse/CALCITE-2591

I have started in another thread the discussion about the actual bug
which led to such situation

Thank you

Enrico

>
> Enrico
>
>> On Fri, Sep 21, 2018 at 10:23 AM Vladimir Sitnikov
>> <sitnikov.vladimir@xxxxxxxxx> wrote:
>> >
>> > Julian>We can't afford to check assumptions in performance-critical code.
>> >
>> > We definitely can afford checks that take a couple of CPU cycles to perform.
>> >
>> > Vladimir
>
> --
>
>
> -- Enrico Olivelli