fix: Skip buffered rows which are not joined with streamed side when checking join filter results

[viirya]

Which issue does this PR close?

Closes #.

Rationale for this change

Found a test failure on Spark SQL test suite in apache/datafusion-comet#553 (https://github.com/apache/datafusion-comet/actions/runs/10498306015/job/29082983619?pr=553).

When checking join filter results for buffered rows, we should exclude those rows which are not joined with streamed side (i.e., null slots in buffered_indices). Otherwise, we may wrongly consider those rows passing join filter results and lack of null joined buffered rows as in the test.

What changes are included in this PR?

Are these changes tested?

Are there any user-facing changes?

[viirya]

I was trying to duplicate the Spark SQL test but the test failure depends on the data distribution. I cannot make it as same as Spark case.

The test case looks like

select * from (
with left as (
    select N, L from (select unnest(make_array(1, 2, 3, 4)) N, unnest(make_array('A', 'B', 'C', 'D')) L) where N <= 4
), right as (
    select N, L from (select unnest(make_array(1, 2, 3, 4)) N, unnest(make_array('A', 'B', 'C', 'D')) L) where N >= 3
)
select * from left full join right on left.N = right.N and left.N != 3
) order by 1, 2, 3, 4;

I want those values to be in same partition to run sort merge join. So the joined batch looks like:

1 A null null
2 B null null # this and above row wrongly considered passing join filter for buffered row [3, C]
3 C 3 C   # join filter => false
4 D 4 D   # join filter => true

The buffered row [3, C] fails join filter. So it should be output as null joined buffered row, but the two above rows are wrongly considered passing join filter for buffered index 0 (i.e., [3, C]), it will not be output in Comet.

[viirya]

The test case in Comet is apache/datafusion-comet#553 (comment)

[comphead]

lgtm @viirya I feel for this test would be nice to have a DataFusion test, but you said it depends on data distribution between record batches

[viirya]

Thanks @comphead

[viirya]

Let me merge this to unblock apache/datafusion-comet#553.