{
  "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 and released managed state. Only2.2legacy sink preparation/admission changes; no production Rust or ownership protocol changes."
  },
  "previous_revision": "1ed09143",
  "previous_revision_note": "Narrow integer collection candidate before the2.2legacy consumer adapter; identical benchmark source is copied into that checkout.",
  "benchmark_source_sha256": "676b843d8bf06b6f48c083213f24beb9f52b349b76c843f7fcfc761cccd6ed90",
  "configuration": {
    "flink": "2.2.1",
    "rows": {
      "legacy_collect": 200000,
      "legacy_array_agg_not_null": 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 source value isNULL. COLLECT ignoresNULL elements; ARRAY replaces them with0 viaCOALESCE, retaining aNOTNULL component type. Keys7mod8areallNULL source groups.",
    "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/legacy translation, submission, runtime row source, managed state, both row/Arrow transposes, released external-row conversion, collect transport and client iterator draining; cluster boot/schema setup excluded",
    "schedule": "alternating stock/native per JVM; separate JVMs per cardinality and phase; no concurrent tests, builds or benchmarks during measurements",
    "value_types": [
      "BIGINT COLLECT(v)",
      "BIGINT NOT NULL ARRAY_AGG(COALESCE(v,CAST(0 AS BIGINT)))"
    ],
    "array_length_note": "Arrays grow to781/782elements at64groups and12/13at4096; the8-value input domain doesnot cap length.",
    "source_value_type": "BIGINT",
    "consumer": "toRetractStream(query,Row.class).executeAndCollect(); all external insert/retract records drained inside timing"
  },
  "trials": [
    {
      "phase": "previous",
      "shape": "legacy_collect",
      "groups": 64,
      "stock_seconds": [
        1.3938062,
        1.381955024,
        1.374083853
      ],
      "native_seconds": [
        1.378298126,
        1.384468674,
        1.375485429
      ],
      "route": "stock fallback, asserted no native work"
    },
    {
      "phase": "previous",
      "shape": "legacy_collect",
      "groups": 4096,
      "stock_seconds": [
        1.376992998,
        1.366609521,
        1.336918337
      ],
      "native_seconds": [
        1.366876576,
        1.359903691,
        1.346664858
      ],
      "route": "stock fallback, asserted no native work"
    },
    {
      "phase": "previous",
      "shape": "legacy_array_agg_not_null",
      "groups": 64,
      "stock_seconds": [
        2.211109535,
        2.205891368,
        2.210781962
      ],
      "native_seconds": [
        2.183062483,
        2.201101186,
        2.189478518
      ],
      "route": "stock fallback, asserted no native work"
    },
    {
      "phase": "previous",
      "shape": "legacy_array_agg_not_null",
      "groups": 4096,
      "stock_seconds": [
        0.558263568,
        0.542521941,
        0.537402362
      ],
      "native_seconds": [
        0.59111651,
        0.554804816,
        0.553129004
      ],
      "route": "stock fallback, asserted no native work"
    },
    {
      "phase": "current",
      "shape": "legacy_collect",
      "groups": 64,
      "stock_seconds": [
        1.413310861,
        1.367508351,
        1.376736703
      ],
      "native_seconds": [
        1.347111778,
        1.347181974,
        1.333859874
      ],
      "route": "consumed NativeJvmGroup and both transposes"
    },
    {
      "phase": "current",
      "shape": "legacy_collect",
      "groups": 4096,
      "stock_seconds": [
        1.363647981,
        1.260053248,
        1.243484111
      ],
      "native_seconds": [
        1.307878934,
        1.243732133,
        1.210967246
      ],
      "route": "consumed NativeJvmGroup and both transposes"
    },
    {
      "phase": "current",
      "shape": "legacy_array_agg_not_null",
      "groups": 64,
      "stock_seconds": [
        2.103231919,
        2.204880277,
        2.099213718
      ],
      "native_seconds": [
        2.444054633,
        2.619671729,
        3.043646128
      ],
      "route": "consumed NativeJvmGroup and both transposes"
    },
    {
      "phase": "current",
      "shape": "legacy_array_agg_not_null",
      "groups": 4096,
      "stock_seconds": [
        0.573536895,
        0.549518939,
        0.537020267
      ],
      "native_seconds": [
        0.552483515,
        0.554459808,
        0.556154858
      ],
      "route": "consumed NativeJvmGroup and both transposes"
    }
  ],
  "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; capture repeated native-only complete jobs until8secondtarget, stopaftercurrentjob. Includesplanning,compilation,collecttransport/client andallJVMthreads. Profiledtimesexcludedfromtrialtable.",
    "captures": {
      "legacy_array_agg_not_null-keys64-native": {
        "total_samples": 24805,
        "inclusive_method_samples": {
          "NativeColumnarJvmGroupOperator.ingest": 8102,
          "NativeColumnarJvmGroupOperator.append": 7030,
          "GroupAggFunction.processElement": 7990,
          "CollectAggFunction.getValue": 0,
          "ArrayAggFunction.getValue": 733,
          "MapWriter.doWrite": 0,
          "ArrayWriter.doWrite": 508,
          "LinkedList.toArray": 734,
          "CollectResultIterator": 5666,
          "ArrayDataSerializer.copy": 165
        },
        "top_self_samples": {
          "java/io/DataOutputStream.writeLong_[i]": 5433,
          "java/io/DataInputStream.readUnsignedByte_[i]": 2714,
          "java/io/ByteArrayInputStream.read_[j]": 2406,
          "java/util/LinkedList.toArray_[i]": 731,
          "_raw_spin_unlock_irqrestore_[k]": 679,
          "java/util/Arrays.setAll_[j]": 416,
          "jbyte_disjoint_arraycopy": 281,
          "IndexSetIterator::advance_and_next": 272,
          "jlong_disjoint_arraycopy": 216,
          "/usr/lib/x86_64-linux-gnu/libc.so.6": 193
        }
      },
      "legacy_collect-keys4096-native": {
        "total_samples": 21768,
        "inclusive_method_samples": {
          "NativeColumnarJvmGroupOperator.ingest": 4116,
          "NativeColumnarJvmGroupOperator.append": 2702,
          "GroupAggFunction.processElement": 4012,
          "CollectAggFunction.getValue": 389,
          "ArrayAggFunction.getValue": 0,
          "MapWriter.doWrite": 296,
          "ArrayWriter.doWrite": 0,
          "LinkedList.toArray": 0,
          "CollectResultIterator": 2184,
          "ArrayDataSerializer.copy": 0
        },
        "top_self_samples": {
          "java/io/ByteArrayInputStream.read_[j]": 1537,
          "org/apache/flink/api/common/typeutils/base/MapSerializer.serialize_[i]": 775,
          "_raw_spin_unlock_irqrestore_[k]": 551,
          "do_syscall_64_[k]": 418,
          "java/util/HashMap.putVal_[i]": 392,
          "org/apache/flink/core/memory/MemorySegment.equalTo_[i]": 360,
          "read": 353,
          "G1ParScanThreadState::trim_queue_to_threshold": 350,
          "java/io/DataInputStream.readInt_[i]": 342,
          "IndexSetIterator::advance_and_next": 280
        }
      }
    },
    "limitations": "Inclusive counts overlap; append includes chained downstream work. Counts are not allocation counts or copied bytes."
  },
  "load_monitor": {
    "interval_seconds": 2,
    "external_workloads_observed_during_trials": 0,
    "external_workloads_observed_during_profiles": 0,
    "raw_matrix_observations": 2,
    "observation_note": "Both raw observations are this matrix ownMaven shell startup commands atphase launch, before firstwarmup/timing. Commands matched the matrix case/library/expectedroute settings. They are not concurrent foreign workloads.",
    "matrix_start_epoch_seconds": 1792864406.668328,
    "matrix_end_epoch_seconds": 1792864597.1962235,
    "phase_intervals": [
      {
        "phase": "current",
        "start_epoch_seconds": 1792864426.7359614,
        "end_epoch_seconds": 1792864512.9709573,
        "exit_code": 0
      },
      {
        "phase": "previous",
        "start_epoch_seconds": 1792864512.9709716,
        "end_epoch_seconds": 1792864597.1962173,
        "exit_code": 0
      }
    ]
  },
  "validation": {
    "flink2.2.1": {
      "passed": 267,
      "skipped": 0
    },
    "flink1.18.1": {
      "passed": 208,
      "skipped": 59
    },
    "agent": {
      "passed": 56,
      "skipped": 1
    },
    "scope_unit_tests": 6,
    "summary_unit_tests": 25,
    "upstream": {
      "method": "AggregateITCase#testUnboundedGroupByCollect",
      "flink2.2.1": {
        "passed": 7,
        "native": 2,
        "fallback": 5
      },
      "flink1.18.1": {
        "passed": 6,
        "native": 2,
        "fallback": 4
      },
      "scope_requirements": {
        "2.2": 115,
        "1.18": 95
      },
      "note": "Originalsource, assertions andfixtureconfiguration unchanged; bothnewscope subsets validate.1.18changelogfalse observed inlocalnativecases;conditionaltruefallbackretained incontracts.",
      "provenance": "Releasedupstream compiledbuild fromcanonicalCI virtualrevisionf7d71d1249a53846ec3ee293fb9e85218951ff07, replacedonlyStreamFusioncorewithproperlypackagedcandidateandnewagent. CIdebugnative libraryrequiresGLIBC2.38 unavailablelocally;correctnessusesverifiedlocalrelease/mimalloc/rocksdb librarywithidenticalproductionRust (onlybenchchanges sincefrozen source),developmentstampmodeenabled.",
      "observed_native_work_per_synchronous_backend_variant": {
        "NativeCalcOperator": 21,
        "NativeColumnarJvmGroupOperator": 21
      }
    },
    "coverage": [
      "four integer widths and direct verified collection-group input",
      "ordered external insert/retract rows, NULLs, DISTINCT andNOTNULL COALESCE elements",
      "NULLarray containers withIGNORENULLS, emptyglobal anddisabledruntime",
      "canonicalcharacter groupingkeys andparallelism1/3",
      "consumedgroup/nativecalc/transposes andmemoryrelease",
      "existing collection/typedJVMaggregate/cast/UNNEST/producer/sink regressions"
    ]
  },
  "scope": {
    "admitted": "2.2legacy row sinks with direct input accepted by existingintegerCOLLECT/ARRAY_AGG groupgate; capturehostproven keys andneedRetraction beforeArrow rewrite.1.18keeps its existingpreparedlegacy path.",
    "retained_fallback": [
      "finalCalc orotherunverified sensitiveproducer/consumer chains",
      "unverifiedelementtypes ornon-scalar aggregateinputs",
      "character aggregate results",
      "mini-batch/local-global/async-state and1.18changelog-state exclusions",
      "updating MAP/MULTISET retained payloads in#437"
    ],
    "not_applicable": "ARRAY_AGG absent onreleased1.18.1."
  },
  "conclusion": "COLLECT medians are lower than pairedstock/prior fallback; process controls drift and wide-group ranges overlap, so no sustainedacceleration claim. Growing NOTNULL ARRAY at64groups is slower thanstock/prior;4096group medians areclose. TwoCPUcaptures identifyserialization/clientcollection asmajor costs, with remaining state/snapshots/output work. No safe small change identified within the boundedpasses. Accepted collectiontradeoff; furtherperformance in#239."
}