Re: Using each rel as both outer and inner for JOIN_ANTI

On Fri, Jul 2, 2021 at 11:59 AM Zhihong Yu <zyu(at)yugabyte(dot)com> wrote:

>
>
> On Thu, Jul 1, 2021 at 8:24 PM Richard Guo <guofenglinux(at)gmail(dot)com> wrote:
>
>>
>> On Thu, Jul 1, 2021 at 3:18 PM Ronan Dunklau <ronan(dot)dunklau(at)aiven(dot)io>
>> wrote:
>>
>>> Le jeudi 1 juillet 2021, 09:09:38 CEST Ronan Dunklau a écrit :
>>> > > Yes, thanks! I was making a big mistake here thinking the executor
>>> can
>>> > > stop after the first match. That's not true. We need to use each
>>> outer
>>> > > tuple to find all the matches and mark the corresponding hashtable
>>> > > entries. I have updated the patch with the fix.
>>> >
>>> > It looks OK to me.
>>>
>>> I forgot to mention: you also have failing tests due to the plans
>>> changing to
>>> use the new join type. This might not be the case anymore once you
>>> update the
>>> cost model, but if that's the case the tests should be updated.
>>>
>>
>> Thanks! Test cases are updated in v3 patch. Also merge join can do the
>> 'right anti join' too in the same patch.
>>
>> Thanks again for reviewing this patch.
>>
>> Thanks
>> Richard
>>
>>
> Hi,
> Minor comment:
> + * In a right-antijoin, we never return a matched
> tuple.
>
> matched tuple -> matching tuple
>

Thanks for reviewing.

The comment for JOIN_ANTI in ExecHashJoinImpl/ExecMergeJoin is:

"In an antijoin, we never return a matched tuple"

So I think we'd better keep it consistent for JOIN_RIGHT_ANTI?

Thanks
Richard