Predicate pushdown in PR #511 supports only single-column-group reads.
When more than one column group exists, PackedRecordBatchReader logs
a warning and ignores the predicate.
To support multi-column-group, the lower-level reader needs to return
a row mask alongside batches so the upper layer can align reads across
column groups.
Captured from review of PR #511:
#511 (comment)
Predicate pushdown in PR #511 supports only single-column-group reads.
When more than one column group exists, PackedRecordBatchReader logs
a warning and ignores the predicate.
To support multi-column-group, the lower-level reader needs to return
a row mask alongside batches so the upper layer can align reads across
column groups.
Captured from review of PR #511:
#511 (comment)