{
  "date": "2026-10-16",
  "issue": 237,
  "source_commit": "84b9cc59830273021954d148c746a2b13713f642",
  "variant": "Primitive STRING hash index with full equality and borrowed probes",
  "rows": 1000000,
  "keys": 32768,
  "warmup_pairs": 2,
  "measured_pairs": 3,
  "native_udaf_input_rows": 5000000,
  "includes": [
    "generated JVM UDAF",
    "native builtin SUM Rust control"
  ],
  "timings_excluded": true,
  "external_cpu_s": 52.83,
  "external_observations": 30,
  "stacks": {
    "cpu": {
      "file": "jvm-aggregate-string-hash-index-cpu-2026-10-16.collapsed.gz",
      "sha256": "a892863261db734d6214a81d1afa7a72708b3756ebfe8e59064c46561948b0d3",
      "inclusive_ingest_total": 1521,
      "units": "samples",
      "inclusive_methods": {
        "stringEntry": 617,
        "JvmAccumulatorCache": 776,
        "LongObjectHashMap.get": 335,
        "BinaryRowDataKeySelector.getKey": 13
      },
      "leading_jvm_leaves": [
        [
          "org/apache/flink/shaded/netty4/io/netty/util/collection/LongObjectHashMap.toExternal_[i]",
          241
        ],
        [
          "tech/streamfusion/operator/JvmAccumulatorCache$CachedState.stringEntry_[i]",
          100
        ],
        [
          "org/apache/flink/shaded/netty4/io/netty/util/collection/LongObjectHashMap.indexOf_[i]",
          91
        ],
        [
          "org/apache/flink/table/data/RowData.lambda$createFieldGetter$245ca7d1$7_[i]",
          80
        ],
        [
          "org/apache/flink/core/memory/MemorySegment.getLong_[i]",
          71
        ],
        [
          "tech/streamfusion/operator/JvmAccumulatorCache$CachedState.keyFor_[i]",
          46
        ],
        [
          "tech/streamfusion/PortableSqlFixtures$Sum.getValue_[i]",
          41
        ],
        [
          "java/lang/Integer.rotateLeft_[i]",
          27
        ],
        [
          "org/apache/flink/core/memory/MemorySegment.get_[i]",
          23
        ],
        [
          "org/apache/flink/table/runtime/operators/aggregate/GroupAggFunction.processElement_[j]",
          21
        ],
        [
          "tech/streamfusion/operator/JvmAccumulatorCache$CachedState.update_[i]",
          21
        ],
        [
          "org/apache/flink/table/data/binary/MurmurHashUtils.mixH1_[i]",
          19
        ]
      ],
      "leading_rust_frames": [
        [
          "streamfusion::group_agg::GroupAggregator<S>::update",
          633
        ],
        [
          "streamfusion::group_agg::output_of",
          88
        ],
        [
          "streamfusion::group_agg::GroupChanges::push",
          33
        ],
        [
          "streamfusion::exchange::coalesce::coalesce_batches",
          21
        ],
        [
          "streamfusion::flink_key::write_value",
          19
        ],
        [
          "streamfusion::aggregates::scalars_to_array",
          17
        ],
        [
          "streamfusion::aggregates::ValueColumn::at",
          9
        ],
        [
          "streamfusion::flink_key::BinaryRowWriter::write_variable",
          9
        ]
      ]
    },
    "alloc": {
      "file": "jvm-aggregate-string-hash-index-alloc-2026-10-16.collapsed.gz",
      "sha256": "96554338bbb246b950a97a49c53630141397b031f4360a3dda11ea221ef78314",
      "inclusive_ingest_total": 4060086272,
      "units": "sampled allocation bytes",
      "inclusive_methods": {
        "JvmAccumulatorCache": 92274688,
        "BinaryRowDataKeySelector.getKey": 62914560
      },
      "leading_jvm_leaves": [
        [
          "java.lang.Object[]_[i]",
          611319808
        ],
        [
          "java.lang.Long_[i]",
          579862528
        ],
        [
          "org.apache.flink.table.data.GenericRowData_[i]",
          570425344
        ],
        [
          "org.apache.flink.core.memory.MemorySegment_[i]",
          533725184
        ],
        [
          "byte[]_[i]",
          363855872
        ],
        [
          "org.apache.flink.table.data.binary.BinaryStringData_[i]",
          341835776
        ],
        [
          "org.apache.flink.table.data.binary.BinarySection_[i]",
          331350016
        ],
        [
          "org.apache.flink.core.memory.MemorySegment[]_[i]",
          241172480
        ],
        [
          "tech.streamfusion.PortableSqlFixtures$SumState_[i]",
          180355072
        ],
        [
          "java.util.concurrent.atomic.AtomicBoolean_[i]",
          147849216
        ],
        [
          "org.apache.flink.streaming.runtime.streamrecord.StreamRecord_[i]",
          127926272
        ],
        [
          "tech.streamfusion.operator.JvmAccumulatorCache$Entry_[i]",
          8388608
        ]
      ],
      "leading_rust_frames": []
    }
  },
  "limitations": [
    "Process-scoped diagnostic profile under recorded external workload; no timing or causal before/after CPU claim",
    "Fixture v1 explains only native before timing; any throughput comparison requires the corrected symmetric-preflight fixture",
    "Inclusive native ingest counts include downstream output copying; allocation samples are not copied bytes or peak memory"
  ]
}