⚡ Bolt: optimize MaybeNullBufferBuilder::take_n#286
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💡 What: Optimized the \`take_n\` method in \`MaybeNullBufferBuilder\` by: 1. Adding a fast path for when no nulls are present. 2. Replacing the manual bit-by-bit loop with optimized Arrow bitwise operations (\`NullBuffer::slice\` and \`NullBufferBuilder::append_buffer\`). 🎯 Why: The previous implementation iterated over every bit individually, which is extremely slow for large batch sizes common in DataFusion. 📊 Impact: - ~660x faster for non-null cases. - ~34x faster for cases with nulls. 🔬 Measurement: Verified with a benchmark test (see \`.jules/bolt.md\` for details). Existing group-by tests pass. Co-authored-by: Dandandan <163737+Dandandan@users.noreply.github.com>
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This PR optimizes the `take_n` method in `MaybeNullBufferBuilder`, which is a critical part of the group-by aggregation engine in DataFusion. By replacing a manual bit-by-bit loop with optimized bitwise operations from Arrow, we achieve a massive performance improvement in emitting batches of results.
Measurements on 100k rows with 8192 batch size:
PR created automatically by Jules for task 4505990081372878565 started by @Dandandan