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https://issues.apache.org/jira/browse/SPARK-57111?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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ASF GitHub Bot updated SPARK-57111:
-----------------------------------
Labels: pull-request-available (was: )
> Use intrinsic bulk-fill APIs for putNotNulls
> --------------------------------------------
>
> Key: SPARK-57111
> URL: https://issues.apache.org/jira/browse/SPARK-57111
> Project: Spark
> Issue Type: Improvement
> Components: SQL
> Affects Versions: 4.3.0
> Reporter: L. C. Hsieh
> Assignee: L. C. Hsieh
> Priority: Major
> Labels: pull-request-available
>
> Follow-up to SPARK-57024 / SPARK-57036.
>
> WritableColumnVector exposes a putNotNulls(rowId, count) method that
> clears a run of the nulls bitmap. It's called once per batch from
> WritableColumnVector.reset() (when numNulls > 0) and from the
> appendNotNulls() path. Both OnHeap and OffHeap implementations are
> per-element loops:
>
> // OnHeap
> for (int i = 0; i < count; ++i) {
> nulls[rowId + i] = (byte)0;
> }
>
> // OffHeap
> long offset = nulls + rowId;
> for (int i = 0; i < count; ++i, ++offset) {
> Platform.putByte(null, offset, (byte) 0);
> }
>
> This is the same pattern fixed for putNulls in SPARK-57024 and for
> putBytes / putBooleans in SPARK-57036. The same intrinsic substitutions
> apply:
> - OnHeap.putNotNulls -> Arrays.fill(byte[], ..., (byte) 0)
> - OffHeap.putNotNulls -> Platform.setMemory(addr, (byte) 0, count)
> with the existing SET_MEMORY_THRESHOLD = 128 fallback to an inline
> byte loop for small counts.
>
> Measured locally on Apple M4 Max + OpenJDK 21 via
> WritableColumnVectorBulkFillBenchmark (a new putNotNulls case added by
> parity (the C2 compiler already auto-vectorizes the original byte
> loop).
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