{
  "date": "2026-10-24",
  "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,
    "operator_note": "Existing columnar JVM group with released COLLECT MapViews or ARRAY_AGG RAW LinkedList accumulators; only narrow integer admission changes."
  },
  "previous_revision": "083ee5cf",
  "previous_revision_note": "Character-key candidate before narrow integer admission; identical benchmark source copied into prior checkout.",
  "benchmark_source_sha256": "3e67819f9ad3f7ac655800ef5fac1dd0d7ad7be39b09f5b81e92d0b9538fcbe1",
  "configuration": {
    "flink": "2.2.1",
    "rows": {
      "collect": 200000,
      "array_agg": 50000
    },
    "parallelism": 1,
    "key_type": "INT",
    "groups": [
      64,
      4096
    ],
    "distinct_values_per_non_null_group": 8,
    "key": "row modulo groups",
    "value": "(row/groups) modulo8; NULL when row modulo8=7",
    "null_note": "Every eighth input value isNULL; key7mod8groups contain onlyNULL elements under defaultRESPECTNULLS.",
    "warmups_per_engine": 2,
    "trials_per_engine": 3,
    "test_heap_gib": 8,
    "jvm_accumulator_cache_entries": 0,
    "key_prefix_note": "Default16 prefix chars unused forINTkeys.",
    "boundary": "planning, submission, runtime Row source, keyed state, both row/Arrow transposes and blackhole row sink; cluster setup and initial explain excluded",
    "schedule": "alternating stock/native per JVM; separate JVMs per cardinality and phase; no concurrent tests, builds or benchmarks during measurements",
    "value_types": [
      "TINYINT via CAST(v AS TINYINT)",
      "SMALLINT via CAST(v AS SMALLINT)"
    ],
    "array_length_note": "The8-value domain does not cap array length: ARRAY_AGG grows to781/782 elements at64 groups and12/13 at4096 groups.",
    "source_value_type": "BIGINT"
  },
  "trials": [
    {
      "phase": "previous",
      "shape": "collect_tinyint",
      "groups": 64,
      "stock_seconds": [
        0.405148034,
        0.397697038,
        0.376843807
      ],
      "native_seconds": [
        0.378628946,
        0.477743227,
        0.409515733
      ],
      "route": "stock fallback"
    },
    {
      "phase": "previous",
      "shape": "collect_smallint",
      "groups": 64,
      "stock_seconds": [
        0.306992042,
        0.317460869,
        0.305180815
      ],
      "native_seconds": [
        0.390241242,
        0.304946497,
        0.308490411
      ],
      "route": "stock fallback"
    },
    {
      "phase": "previous",
      "shape": "collect_tinyint",
      "groups": 4096,
      "stock_seconds": [
        0.421993233,
        0.534294402,
        0.418189167
      ],
      "native_seconds": [
        0.460230122,
        0.473465345,
        0.479072739
      ],
      "route": "stock fallback"
    },
    {
      "phase": "previous",
      "shape": "collect_smallint",
      "groups": 4096,
      "stock_seconds": [
        0.358079686,
        0.342139279,
        0.332219735
      ],
      "native_seconds": [
        0.427020669,
        0.353041155,
        0.351100174
      ],
      "route": "stock fallback"
    },
    {
      "phase": "previous",
      "shape": "array_agg_tinyint",
      "groups": 64,
      "stock_seconds": [
        0.738645582,
        0.587040517,
        0.588082098
      ],
      "native_seconds": [
        0.664180735,
        0.602795549,
        0.643704399
      ],
      "route": "stock fallback"
    },
    {
      "phase": "previous",
      "shape": "array_agg_smallint",
      "groups": 64,
      "stock_seconds": [
        0.634633708,
        0.507226931,
        0.525547225
      ],
      "native_seconds": [
        0.574309354,
        0.56670482,
        0.546967684
      ],
      "route": "stock fallback"
    },
    {
      "phase": "previous",
      "shape": "array_agg_tinyint",
      "groups": 4096,
      "stock_seconds": [
        0.19421834,
        0.174585326,
        0.168302893
      ],
      "native_seconds": [
        0.200184085,
        0.167389707,
        0.194958336
      ],
      "route": "stock fallback"
    },
    {
      "phase": "previous",
      "shape": "array_agg_smallint",
      "groups": 4096,
      "stock_seconds": [
        0.157025261,
        0.088241242,
        0.115530663
      ],
      "native_seconds": [
        0.178126281,
        0.091185376,
        0.091072163
      ],
      "route": "stock fallback"
    },
    {
      "phase": "current",
      "shape": "collect_tinyint",
      "groups": 64,
      "stock_seconds": [
        0.426807896,
        0.384039717,
        0.377551397
      ],
      "native_seconds": [
        0.450482562,
        0.395221147,
        0.46271086
      ],
      "route": "consumed NativeJvmGroup"
    },
    {
      "phase": "current",
      "shape": "collect_smallint",
      "groups": 64,
      "stock_seconds": [
        0.373922543,
        0.303697464,
        0.334492077
      ],
      "native_seconds": [
        0.317837811,
        0.31671062,
        0.316301025
      ],
      "route": "consumed NativeJvmGroup"
    },
    {
      "phase": "current",
      "shape": "collect_tinyint",
      "groups": 4096,
      "stock_seconds": [
        0.439195204,
        0.419148068,
        0.395667914
      ],
      "native_seconds": [
        0.493479623,
        0.444146074,
        0.427199372
      ],
      "route": "consumed NativeJvmGroup"
    },
    {
      "phase": "current",
      "shape": "collect_smallint",
      "groups": 4096,
      "stock_seconds": [
        0.359676924,
        0.360388449,
        0.3321192
      ],
      "native_seconds": [
        0.351689733,
        0.467923833,
        0.369802315
      ],
      "route": "consumed NativeJvmGroup"
    },
    {
      "phase": "current",
      "shape": "array_agg_tinyint",
      "groups": 64,
      "stock_seconds": [
        0.556293269,
        0.60713664,
        0.666530979
      ],
      "native_seconds": [
        0.722008916,
        0.729608573,
        0.658593635
      ],
      "route": "consumed NativeJvmGroup"
    },
    {
      "phase": "current",
      "shape": "array_agg_smallint",
      "groups": 64,
      "stock_seconds": [
        0.710872231,
        0.533383578,
        0.68598416
      ],
      "native_seconds": [
        0.746777801,
        0.638138022,
        0.725946659
      ],
      "route": "consumed NativeJvmGroup"
    },
    {
      "phase": "current",
      "shape": "array_agg_tinyint",
      "groups": 4096,
      "stock_seconds": [
        0.216099976,
        0.185945878,
        0.188955993
      ],
      "native_seconds": [
        0.213036773,
        0.192006361,
        0.182820736
      ],
      "route": "consumed NativeJvmGroup"
    },
    {
      "phase": "current",
      "shape": "array_agg_smallint",
      "groups": 4096,
      "stock_seconds": [
        0.193721069,
        0.097794488,
        0.095425819
      ],
      "native_seconds": [
        0.173542139,
        0.100761807,
        0.091968248
      ],
      "route": "consumed NativeJvmGroup"
    }
  ],
  "cpu_profiles": {
    "passes": 2,
    "closed": true,
    "event": "cpu",
    "interval": "1ms",
    "target_seconds_per_capture": 8,
    "profiler": "async-profiler4.6",
    "boundary": "one unprofiled native-only complete-job warmup; profile native-only jobs until the8second target completes, including planning/compilation/allJVMthreads; stop after currentjob",
    "captures": {
      "array_agg_tinyint-keys64-native": {
        "total_samples": 15295,
        "inclusive_method_samples": {
          "NativeColumnarJvmGroupOperator.ingest": 5220,
          "NativeColumnarJvmGroupOperator.append": 1121,
          "GroupAggFunction.processElement": 5153,
          "CollectAggFunction.getValue": 0,
          "ArrayAggFunction.getValue": 3441,
          "MapWriter.doWrite": 0,
          "ArrayWriter.doWrite": 483,
          "ArrayDataSerializer.copy": 526,
          "LinkedList.toArray": 3435
        },
        "top_self_samples": {
          "java/util/LinkedList.toArray_[i]": 3408,
          "_raw_spin_unlock_irqrestore_[k]": 614,
          "org/apache/flink/table/data/columnar/ColumnarArrayData.isNullAt_[i]": 524,
          "org/apache/flink/table/data/GenericRowData.<init>_[i]": 413,
          "IndexSetIterator::advance_and_next": 289,
          "tech/streamfusion/arrow/writers/ArrayWriter.doWrite_[j]": 236,
          "org/apache/arrow/vector/BaseFixedWidthVector.handleSafe_[i]": 194,
          "PhaseChaitin::Split": 182,
          "/usr/lib/x86_64-linux-gnu/libc.so.6": 176,
          "PhaseChaitin::gather_lrg_masks": 132
        }
      },
      "collect_smallint-keys4096-native": {
        "total_samples": 19872,
        "inclusive_method_samples": {
          "NativeColumnarJvmGroupOperator.ingest": 4132,
          "NativeColumnarJvmGroupOperator.append": 1017,
          "GroupAggFunction.processElement": 3855,
          "CollectAggFunction.getValue": 876,
          "ArrayAggFunction.getValue": 0,
          "MapWriter.doWrite": 356,
          "ArrayWriter.doWrite": 0,
          "ArrayDataSerializer.copy": 0,
          "LinkedList.toArray": 0
        },
        "top_self_samples": {
          "_raw_spin_unlock_irqrestore_[k]": 929,
          "IndexSetIterator::advance_and_next": 395,
          "org/apache/flink/runtime/state/heap/CopyOnWriteStateMap.get_[i]": 368,
          "java/util/HashMap.put_[i]": 310,
          "PhaseChaitin::Split": 308,
          "org/apache/flink/core/memory/MemorySegment.equalTo_[i]": 265,
          "PhaseChaitin::gather_lrg_masks": 254,
          "/usr/lib/x86_64-linux-gnu/libc.so.6": 245,
          "java/util/HashMap.putVal_[j]": 245,
          "org/apache/flink/table/data/binary/MurmurHashUtils.hashBytesByInt_[i]": 244
        }
      }
    },
    "limitations": "inclusive counts overlap; not allocation counts/copied bytes, and profiled times do not enter trial tables"
  },
  "scope": {
    "admitted": "Exact builtin COLLECT overTINYINT/SMALLINT onbothlines and ARRAY_AGG overthose types onreleased2.2; same scalar-input, non-character aggregate-result and consumer gates.",
    "retained_fallback": [
      "Other unverified collection element types",
      "Character aggregate values or co-results",
      "Non-scalar aggregate inputs or unverified represented consumers",
      "Updating MAP/MULTISET retained payloads in#437"
    ],
    "not_applicable": "ARRAY_AGG absent fromreleased1.18.1."
  },
  "validation": {
    "flink2.2.1": {
      "passed": 253,
      "skipped": 0
    },
    "flink1.18.1": {
      "passed": 202,
      "skipped": 51
    },
    "coverage": [
      "direct BYTE/SHORT runtime sources, both signed limits and NULLs",
      "duplicates, DISTINCT/FILTER, ordered changelog histories and schemas",
      "empty grouped/global and allNULL results",
      "formatting and validNOTNULL COALESCE outputs",
      "ARRAY RESPECT/IGNORENULLS andconsumed TopN/UNNEST",
      "two nonempty heap/nativeRocksDB restores and memory release",
      "deferred#437MULTISET rank fallback",
      "existing integer/character-key aggregates, scalarUDAF, MULTISETcast, generatedUNNEST andproducer/sink guards"
    ]
  },
  "conclusion": "Most native medians exceed stock; relative prior results vary. Short jobs and overlapping ranges do not establish sustained acceleration. Two profiling passes closed: managed-state/result snapshots, linked-list materialization, output writing and startup/compilation remain. No safe small shortcut found; accepted bounded collection tradeoff, further performance in#239."
}