feat: AVG skips SQL NULLs via per-column validity bitmap - #11
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VedantMadane wants to merge 1 commit into
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feat: AVG skips SQL NULLs via per-column validity bitmap#11VedantMadane wants to merge 1 commit into
VedantMadane wants to merge 1 commit into
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Scoped NULL spike (basalt-db#10): mark explicit INSERT NULLs on Column::nullmask and make AVG ignore them (divide by non-NULL count), keeping the empty-bitmap fast path for importers/benches. Document coverage and remaining NULL work. Closes basalt-db#10 Signed-off-by: Vedant Madane <6527493+VedantMadane@users.noreply.github.com>
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Summary
Scoped spike for #10: make
AVGskip SQL NULLs using a per-column validity signal, without regressing the all-valid fast path.What changed
Column::nullmask(+is_null_at/set_null_at); empty mask = historical all-valid pathINSERT ... NULLmarks validity (placeholder 0/""still stored underneath)AVGuses non-NULL count; all-NULL → SQLNULLdocs/NULL_AVG_SPIKE.md(covered vs TODO); pointer inGOOD_FIRST_ISSUES.mdNot in this PR (called out in the spike doc)
Disk-persisted validity, importer
\Nmapping, full SUM/MIN/MAX/COUNT(col)/WHERE three-valued logic, projecting NULL cells.Test plan
make clean && make(Linux CI / native; this agent is Windows withoutmmap)basalt-bench 1000000 50000 3still all checks pass (no NULL bitmap on bench data)INSERTmix of values + NULL,SELECT AVG(v)matches SQLite (20 for 10/NULL/30)Related
Closes #10