Description

StringView dictionary decoding currently goes through an intermediate index buffer: decode indices → gather views. For RLE runs (which are common), this roundtrip is unnecessary.

Proposed Changes

• For RLE runs, use repeat_n to fill views directly, skipping the index buffer entirely
• Pre-reserve output views capacity before the decode loop, eliminating per-chunk reallocation
• Skip buffer management when all dictionary views are inlined (≤12 bytes)
• Pre-reserve offsets in ByteArray dictionary decoding

This eliminates the intermediate index buffer roundtrip for the common RLE case and reduces StringView dictionary decoding time by ~49% in benchmarks.

🤖 Generated with Claude Code