Handle nullptr return value from bitmask_or in distinct_count #13590
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If nulls should compare equal then we want to filter out rows for which all column entries are invalid (bitmask not set). If any column is not nullable, then bitmask_or returns an empty bitmask buffer (and a null count of zero) indicating that the returned bitmask is fully valid. When passed as a predicate to insert_if we get a null pointer dereference. To avoid this, only run predicated insertion if the null count returned from bitmask_or is positive (which guarantees that the validity bitmask exists). This also avoids running predicated insertion when the predicate is always true. Closes rapidsai#13576.
davidwendt
reviewed
Jun 20, 2023
|
I ran my tests with this patch and I saw no crashes for any of TPCDS, so I am happy with it. |
Thanks for confirming! |
ttnghia
approved these changes
Jun 20, 2023
PointKernel
approved these changes
Jun 20, 2023
|
/merge |
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Description
If nulls should compare equal then we want to filter out rows for which all column entries are invalid (bitmask not set). If any column is not nullable, then bitmask_or returns an empty bitmask buffer (and a null count of zero) indicating that the returned bitmask is fully valid. When passed as a predicate to insert_if we get a null pointer dereference.
To avoid this, only run predicated insertion if the null count returned from bitmask_or is positive (which guarantees that the validity bitmask exists). This also avoids running predicated insertion when the predicate is always true.
Closes #13576.
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