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

On Thu, Mar 7, 2019 at 8:20 PM amul sul <sulamul(at)gmail(dot)com> wrote:

>
>
> On Thu, Mar 7, 2019 at 1:02 PM amul sul <sulamul(at)gmail(dot)com> wrote:
>
>> Thanks Rajkumar,
>>
>> I am looking into this.
>>
>>
> The crash happens when none of the if-else branch of
> handle_missing_partition()
> evaluates and returns merged_index unassigned.
>
> Let me explain, in Rajkumar 's test case, the join type is JOIN_INNER.
> When
> only outer rel has null partition, merge_null_partitions() function calls
> handle_missing_partition() with missing_side_inner = false and
> missing_side_outer = false
>

Both missing_side_ variables being false when the NULL partition is missing
on the inner side looks suspicious. I guess from the variable names that
the missing_side_inner should be true in this case.

> 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.

--
Best Wishes,
Ashutosh Bapat