{ "date": "2026-10-15", "issue": 365, "source_base": "35b54e57771f92de9dfc649d8800f797b907fbd2", "production_source_sha256": { "native/engine/src/exchange.rs": "eb1caa45ff2486c81d6b42cd245a3fd0f7fa9ba6425236eff614fbdada3ce3c1", "native/engine/src/exchange/coalesce.rs": "967bb95dd3f6834e896ec53abf72e3abb706d3f15263fcf8e045d4a9a4856e27", "src/main/java/tech/streamfusion/operator/BatchCoalescer.java": "7fb66e354756e1a0dc6b7c9a20eb4f49b29aad70459675f5566879245e33fc3e" }, "native_library_sha256": { "baseline": "598e5373cd81e459a749e27a0fb2734e6ed40e3d6def8c093a935e13ca40cfb8", "fixed": "24cef157092f0564f6f6c70a1d0f3d92169dd4a4c6b6fffede564cc566e96e0c" }, "environment": { "flink": "2.2.1", "jdk": "17", "rustc": "rustc 1.94.0 (4a4ef493e 2026-03-02)", "cpu_model": "12th Gen Intel(R) Core(TM) i7-12650H", "parallelism": 1, "backend": "memory", "release": true, "features": [ "mimalloc", "rocksdb-state" ] }, "query": "SELECT k, SUM(v) AS v FROM (SELECT k, v FROM (SELECT s AS k, d AS v FROM src) s UNION ALL SELECT k, SUM(v) AS v FROM (SELECT s AS k, d AS v FROM src) s GROUP BY k) u GROUP BY k", "fixture": "BasicTypeBenchmark bounded RowData source: 991 distinct STRING values plus NULL, nullable DECIMAL(7,2); every seventh row has NULL key and value", "end_to_end_boundary": "Complete submitted row-source to rowwise blackhole jobs, including both transposes, JNI, native state, and Arrow IPC shuffle. Warmups execute before five retained runs; stock/native ordering alternates each trial.", "configuration": { "warmups": 2, "runs": 5, "mini_batch": false, "zero_copy_local": false, "transpose_rows": 1024, "coalesce_latency_ms": 50, "sf_test_forks": 1 }, "reproduce_fixed": "SF_BENCHMARK=true mvn test -Pbench -pl streamfusion-runtime -am -Dtest=MixedUnionBenchmark -Dsurefire.failIfNoSpecifiedTests=false -Dbasic.rows=2000000 -Dbasic.keys=991 -Dbasic.warmup=2 -Dbasic.runs=5 -Dbasic.miniBatch=false", "baseline_method": "Copied the same benchmark fixture into a worktree at source_base, retaining its unmodified production Java and Rust. Default coalescing failed at both sizes; baseline-control changes only coalesceRows to 1.", "limitations": [ "Default baseline returns incorrect sums in the four-row SQL regression and intermittently panics at both larger sizes; partial timings are retained but are not successful speed comparisons.", "The 200000-row jobs show substantial startup/JIT variability. These complete-job times do not isolate steady-state processing.", "The fixed-default and disabled-coalescing baseline controls have different coalescing settings; their timing difference is not a controlled optimization speedup.", "Criterion reports allocation requests and output buffer sharing, not copied-byte counts; JNI and Flink scheduling are outside its timed boundary." ], "correctness": { "flink22": [ { "suite": "tech.streamfusion.FlinkMixedUnionSqlHarnessTest", "tests": 22, "failures": 0, "errors": 0, "skipped": 0 }, { "suite": "tech.streamfusion.FlinkUnionSqlHarnessTest", "tests": 7, "failures": 0, "errors": 0, "skipped": 0 }, { "suite": "tech.streamfusion.operator.BatchCoalescerTest", "tests": 7, "failures": 0, "errors": 0, "skipped": 0 } ], "flink118": [ { "suite": "tech.streamfusion.FlinkMixedUnionSqlHarnessTest", "tests": 22, "failures": 0, "errors": 0, "skipped": 0 }, { "suite": "tech.streamfusion.FlinkUnionSqlHarnessTest", "tests": 7, "failures": 0, "errors": 0, "skipped": 0 }, { "suite": "tech.streamfusion.operator.BatchCoalescerTest", "tests": 7, "failures": 0, "errors": 0, "skipped": 0 } ], "canonical_baseline": { "tests": 16, "failures": 12, "errors": 0, "skipped": 0 } }, "rust_regressions": { "selected": 4, "passed": 4 }, "criterion": { "fixtures": 24, "sample_size": 20, "warmup_seconds": 1, "measurement_seconds": 1, "cases": [ { "case": "append/rows=1024/width=256", "median_ns": { "confidence_interval": { "confidence_level": 0.95, "lower_bound": 8981.58917273576, "upper_bound": 9081.736666666668 }, "point_estimate": 9008.920201058201, "standard_error": 21.577417734635038 }, "allocation_requests": 22, "requested_bytes": 491668, "shared_output_buffer_bytes": 0, "new_output_buffer_bytes": 490500 }, { "case": "append/rows=1024/width=8", "median_ns": { "confidence_interval": { "confidence_level": 0.95, "lower_bound": 1636.3117718570581, "upper_bound": 1660.0596570954422 }, "point_estimate": 1650.5871541044344, "standard_error": 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