Abhishek | Infra/System's Engineer

#10436 #10510 #10596

Diagnosed a cardinality crossover between indexed gathering and direct per-row view construction, characterizing when each strategy is faster.
Engineered cardinality-gated fast paths across Utf8/Binary variants, with safe/strict Binary/LargeBinary→Utf8View validation, oversized-buffer fallback, and null-value preservation.
Two Apache Neoverse-V2 runs measured dense casting at 46.2→16.5μs (64.3%) and sparse Binary→Utf8View at 159.7→57.4μs and 159.2→44.7μs (64.1% to 71.9%); correctness was validated against take-then-cast.

#5455 #5380

Replaced per-row O(log K) BinaryHeap push/pop with amortized O(1) Vec buffering plus linear QuickSelect at 2K boundaries, preserving per-segment Top-K results.
Absorbed a direct-child VisibilityFilterExec into SegmentedTopKExec; visibility plans use per-segment buffer capacity max(2K, 8,192) and remove MVCC-invisible rows before QuickSelect, cutoff derivation and threshold publication.
Locally validated PostgreSQL-equivalent output on a 30,000-row early-prune workload; passed randomized multi-segment Top-K property tests, join/sort integration, mpp_joinscan and all 292 regression tests.

#962

Avoided repeated full-file SHA-256 reads for unchanged direct-GGUF sources by reusing persisted digests on validated cache hits.
Validated canonical path, size, mtime and ctime where supported; enforced version, algorithm and digest checks, non-UTF-8-path bypass, concurrent-writer-safe write-then-rename publication and fail-open cache handling.
A local cache-hit probe reduced unchanged 1-GiB validation from approximately 650 ms to 80–125 μs, about 99.98% lower latency; added 18 tests covering invalidation, corruption, replacement, write failures and concurrent writers.

#9379

Added arrow-json reader/writer support for Run-End Encoded arrays; the reader dispatches Int16/Int32/Int64 run-end indexes, while the writer maps logical indexes to physical values.
Implemented consecutive equal-value and null-run coalescing, checked run-end overflow, empty-input construction and explicit safety invariants for unchecked ArrayData construction.
Added seven tests covering reads, round trips, null runs, unique values, Int16/Int32 run ends and string/integer values.

Hi, I'm Abhishek - Infra/System's Engineer.