Re: [HACKERS] advanced partition matching algorithm for partition-wise join

Attached version is rebase atop of the latest master head(fdc7efcc30), also
incorporates the Ashutosh's suggestion, thanks.

Regards,
Amul

On Mon, Mar 11, 2019 at 10:14 PM Ashutosh Bapat <
ashutosh(dot)bapat(dot)oss(at)gmail(dot)com> wrote:

>
>
> On Mon, Mar 11, 2019 at 10:40 AM amul sul <sulamul(at)gmail(dot)com> wrote:
>
>>
>> All the places from where this handle_missing_partition() get called
>> have the following code to decide the value for missing_side_outer/_inner
>> which
>> I yet to understand. Do you think this has some flaw?
>>
>> /*
>> * For a FULL join, inner relation acts as both OUTER and INNER
>> * relation. For LEFT and ANTI join the inner relation acts as
>> * INNER relation. For INNER and SEMI join OUTER and INNER
>> * differentiation is immaterial.
>> */
>> missing_side_inner = (jointype == JOIN_FULL ||
>> jointype == JOIN_LEFT ||
>> jointype == JOIN_ANTI);
>> missing_side_outer = (jointype == JOIN_FULL);
>>
>
> I was wrong, sorry. The comment says it all.
>
>
>>
>>
>>
>>> argument value which fails to set merged_index.
>>>>
>>>> In the attached patch, I tried to fix this case by setting merged_index
>>>> explicitly which fixes the reported crash.
>>>>
>>>
>>> I expect handle_missing_partition() to set the merged_index always. In
>>> your patches, I don't see that function in your patches is setting it
>>> explicitly. If we are setting merged_index explicitly somewhere else, other
>>> places may miss that explicit assignment. So it's better to move it inside
>>> this function.
>>>
>>>
>>
>> Ok, that can be fixed.
>>
>> Similarly, I think merge_null_partitions should set null_index instead of
>> asserting when null partitions missing from both the side, make sense?
>>
>
> I think not. null_index, once set shouldn't change and hence does not
> change with each pair of partitions being matched. So, it makes sense to
> make sure that null_index remains invalid if none of the tables have null
> partition.
>
> --
> Best Wishes,
> Ashutosh Bapat
>