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Posted to dev@ignite.apache.org by Max Timonin <ti...@gmail.com> on 2021/02/02 15:18:55 UTC

Re:

Closed.

I've recreated a topic, as forget about the topic title there.

On Tue, Feb 2, 2021 at 6:17 PM Max Timonin <ti...@gmail.com> wrote:

> Hi, Igniters!
>
> Last week I investigated a bug [1]. It's about an incorrect result for
> non-colocated joins. For such joins it's required to set up the
> "distributedJoin" flag, or try to make joined tables colocated. It is
> covered in docs [2]. But it's not obvious and some users don't read that or
> forget about that. In result there are wrong results for some queries that
> are pretty hard to debug.
>
> There is a ticket [3] with a comment, where it's suggested to add a check
> for such joins. I tried to implement it and found a place where it's
> possible to put this check. But there is an open question what this check
> should do. Currently I see 2 ways for that:
> 1. Forbid non-colocated joins that aren't marked with the distributedJoin
> flag, and throw an exception.
> 2. Check every query for such joins and implicitly setup a distributedJoin
> flag for them.
>
> Both solutions may break compatibility, but is this compatibility OK?
>
> Igniters, what do you think?
>
> [1] https://issues.apache.org/jira/browse/IGNITE-12847
> [2]
> https://ignite.apache.org/docs/latest/SQL/distributed-joins#distributed-joins
> [3] https://issues.apache.org/jira/browse/IGNITE-13019
>