{
  "date": "2026-10-24",
  "previous_revision": "d48fba98",
  "previous_revision_note": "Measured previous code is the PR476 candidate tree atd48fba98; this exact commit is retained by the canonical merge. This increment is prepared separately and merges after476.",
  "hardware": {
    "cpu": "Intel Core i7-12650H",
    "os": "Linux x86-64 / WSL2",
    "jdk": "OpenJDK17.0.20.1"
  },
  "native": {
    "profile": "release",
    "features": [
      "mimalloc",
      "rocksdb-state"
    ],
    "sha256": "b574491f08427c8b128107d6286cb403421a0bafbdba7a0e5cdd8fea30562d16",
    "production_rust_changes": false,
    "note": "Same frozen DSO for all phases; this admission reuses the generated evaluator and existing Arrow map transport."
  },
  "configuration": {
    "flink": "2.2.1",
    "rows": 250000,
    "parallelism": 1,
    "multiset_entries": [
      4,
      32
    ],
    "key_type": "nullable INT",
    "value_type": "INT NOT NULL multiplicities",
    "keys": "i*257 for i0..entries-2, thenNULL",
    "multiplicities": "i%3+1 for integer keys;3 forNULL",
    "null_container_every": 8,
    "warmups_per_engine": 2,
    "measured_trials_per_engine": 3,
    "test_heap_gib": 8,
    "input": "runtime source emits internal GenericRowData/ordered GenericMapData registered with public InternalTypeInfo; immutable prepared key/count map is shared by source rows",
    "boundary": "planning, submission, runtime RowData source, both row/Arrow transposes and blackhole row sink; cluster setup and initial explain excluded",
    "schedule": "separate JVMs per phase/cardinality; alternating stock/native trials; no concurrent tests, native compilation or other benchmarks during timing",
    "metadata_note": "CSVmultiset_entries selects cardinality; payload_bytes264/unicodefalse are unused text defaults andbinary_width0 is unused."
  },
  "trials": [
    {
      "phase": "previous",
      "entries": 4,
      "function": "BASELINE_tt_multiset",
      "flink_seconds": [
        0.153136,
        0.179537,
        0.147468
      ],
      "native_seconds": [
        0.24797,
        0.174434,
        0.23005
      ]
    },
    {
      "phase": "previous",
      "entries": 4,
      "function": "MULTISET_CAST",
      "flink_seconds": [
        0.189486,
        0.185551,
        0.192012
      ],
      "native_seconds": [
        0.191836,
        0.199897,
        0.188395
      ]
    },
    {
      "phase": "previous",
      "entries": 4,
      "function": "MULTISET_FORMAT_STRING",
      "flink_seconds": [
        0.253825,
        0.212593,
        0.214966
      ],
      "native_seconds": [
        0.229614,
        0.224224,
        0.21641
      ]
    },
    {
      "phase": "previous",
      "entries": 32,
      "function": "BASELINE_tt_multiset",
      "flink_seconds": [
        0.330093,
        0.230552,
        0.311527
      ],
      "native_seconds": [
        0.372013,
        0.387952,
        0.382415
      ]
    },
    {
      "phase": "previous",
      "entries": 32,
      "function": "MULTISET_CAST",
      "flink_seconds": [
        0.457905,
        0.456516,
        0.48702
      ],
      "native_seconds": [
        0.466342,
        0.454004,
        0.456071
      ]
    },
    {
      "phase": "previous",
      "entries": 32,
      "function": "MULTISET_FORMAT_STRING",
      "flink_seconds": [
        0.551747,
        0.474598,
        0.486363
      ],
      "native_seconds": [
        0.510621,
        0.493186,
        0.480225
      ]
    },
    {
      "phase": "final",
      "entries": 4,
      "function": "BASELINE_tt_multiset",
      "flink_seconds": [
        0.160699,
        0.154811,
        0.152269
      ],
      "native_seconds": [
        0.223612,
        0.256733,
        0.171959
      ]
    },
    {
      "phase": "final",
      "entries": 4,
      "function": "MULTISET_CAST",
      "flink_seconds": [
        0.187421,
        0.182766,
        0.185376
      ],
      "native_seconds": [
        0.261849,
        0.246239,
        0.253451
      ]
    },
    {
      "phase": "final",
      "entries": 4,
      "function": "MULTISET_FORMAT_STRING",
      "flink_seconds": [
        0.226101,
        0.219468,
        0.252986
      ],
      "native_seconds": [
        0.287859,
        0.286316,
        0.290994
      ]
    },
    {
      "phase": "final",
      "entries": 32,
      "function": "BASELINE_tt_multiset",
      "flink_seconds": [
        0.318544,
        0.223621,
        0.232203
      ],
      "native_seconds": [
        0.438326,
        0.449767,
        0.538035
      ]
    },
    {
      "phase": "final",
      "entries": 32,
      "function": "MULTISET_CAST",
      "flink_seconds": [
        0.470641,
        0.466856,
        0.46292
      ],
      "native_seconds": [
        0.756718,
        0.75628,
        0.752158
      ]
    },
    {
      "phase": "final",
      "entries": 32,
      "function": "MULTISET_FORMAT_STRING",
      "flink_seconds": [
        0.491673,
        0.479175,
        0.542994
      ],
      "native_seconds": [
        0.71321,
        0.718291,
        0.727207
      ]
    }
  ],
  "cpu_profiles": {
    "passes": 2,
    "closed": true,
    "profiler": "async-profiler4.6",
    "event": "cpu",
    "interval": "1ms",
    "seconds_per_capture": 8,
    "multiset_entries": 32,
    "captures": {
      "multiset_cast-native": {
        "total_samples": 12872,
        "inclusive_method_samples": {
          "NativeUdf.invokeUdf": 3793,
          "FlinkExpressionFunction.evalRow": 2209,
          "MapWriter.doWrite": 2277,
          "NestedStringWriter.doWrite": 0,
          "MapDataSerializer.toBinaryMap": 2812,
          "ArrayDataSerializer.toBinaryArray": 0
        },
        "top_self_samples": {
          "org/apache/flink/table/runtime/typeutils/MapDataSerializer.toBinaryMap_[j]": 701,
          "org/apache/flink/table/data/writer/BinaryWriter.write_[j]": 662,
          "tech/streamfusion/arrow/writers/MapWriter.doWrite_[j]": 653,
          "org/apache/flink/table/data/writer/BinaryArrayWriter.complete_[i]": 576,
          "FlinkExpressionEvaluator$10.eval_[j]": 440,
          "tech/streamfusion/arrow/writers/ArrowFieldWriter.write_[i]": 316,
          "_raw_spin_unlock_irqrestore_[k]": 273,
          "org/apache/arrow/vector/BaseFixedWidthVector.setNull_[i]": 271,
          "java/lang/Long.valueOf_[i]": 242,
          "java/util/HashMap.valuesToArray_[i]": 239
        }
      },
      "multiset_format_string-native": {
        "total_samples": 15115,
        "inclusive_method_samples": {
          "NativeUdf.invokeUdf": 4007,
          "FlinkExpressionFunction.evalRow": 3303,
          "MapWriter.doWrite": 908,
          "NestedStringWriter.doWrite": 323,
          "MapDataSerializer.toBinaryMap": 1907,
          "ArrayDataSerializer.toBinaryArray": 0
        },
        "top_self_samples": {
          "tech/streamfusion/arrow/writers/MapWriter.doWrite_[j]": 813,
          "java/lang/Integer.getChars_[i]": 500,
          "org/apache/flink/table/data/writer/BinaryWriter.write_[j]": 449,
          "org/apache/flink/table/runtime/typeutils/MapDataSerializer.toBinaryMap_[j]": 371,
          "java/lang/Integer.valueOf_[i]": 348,
          "jbyte_disjoint_arraycopy": 319,
          "IndexSetIterator::advance_and_next": 288,
          "FlinkExpressionEvaluator$18.eval_[j]": 282,
          "_raw_spin_unlock_irqrestore_[k]": 261,
          "PhaseChaitin::Split": 232
        }
      }
    },
    "limitations": "all JVM threads including planning and compilation; inclusive counts overlap and do not measure allocations or copied bytes"
  },
  "scope": {
    "admitted": "standalone matching MULTISET casts and MULTISET-to-STRING/VARCHAR/CHAR CAST/TRY_CAST through existing generated evaluator and map-shaped Arrow bridge; nullable elements when preserving collections",
    "retained_fallback": [
      "direct fixed BINARY MULTISET elements",
      "external STRUCTURED inputs",
      "unverified represented state/exchange/ordering/native-writer boundaries",
      "updating MAP/MULTISET retained payload extension#437"
    ],
    "not_implemented": [
      "COLLECT",
      "ARRAY_AGG"
    ]
  },
  "conclusion": "Final complete-job native cases remain slower than paired stock and previous fallback. Two profiling/optimization passes found serialization, Arrow map writing and generated formatting costs; no safe small shortcut was identified. Ship under accepted collection tradeoff without an acceleration claim; further optimization#392. No performance-only opt-in.",
  "validation": {
    "flink2.2.1": {
      "passed": 232,
      "skipped": 0
    },
    "flink1.18.1": {
      "passed": 197,
      "skipped": 35
    },
    "coverage": [
      "runtime sources and consumed NativeCalc",
      "matching/character casts, declared types and legacy rules",
      "NULL/empty containers, NULL elements, multiplicities and narrowing collisions",
      "nested ROW/ARRAY elements, DECIMAL and UTF16 strings",
      "whole-container TRY_CAST failure, CASE/filter/empty batches",
      "all4inputRowKinds",
      "nullable MULTISET inside ROW/ARRAY constructors; standaloneJSON_STRING fallback",
      "directfixedBINARYelement, disableflag andnumericMULTISETstate fallback"
    ]
  }
}