Remove obsolete benchmarks and timing-only unit tests

[xiangfu0]

Summary

The benchmark module contains duplicate workloads, retired implementation experiments, and standalone runners that no longer produce useful measurements. Normal unit-test runs also include an ad hoc interner benchmark with about 737 million calls and a 400,000-segment retention test that only checks elapsed time.

Remove 10 obsolete benchmark classes, the unused LazyDataList helper, three unregistered off-heap ID-map methods, and five obsolete launcher entries. Add a README guide pointing to current workload benchmarks. Production behavior is unchanged.

Benchmark removals

Removed benchmark	Reason
BenchmarkSumQuery	Exact SUM workload duplicate of retained SumIntAggregationFunctionBenchmark, which also compares SUMINT.
StringDictionaryPerfTest	Deletes its segment after lookup, then attempts to reload it for the next measurement; retained JMH dictionary benchmarks cover lookup and reads.
RawIndexBenchmark	Reads STRING columns through numeric conversion and measures v1-style files although new segments default to v3; retain current raw reader/writer benchmarks.
ForwardIndexWriterBenchmark	Unfinished file-based size experiment with an unpopulated offsets array and no timing.
BenchmarkOffHeapDictionaryMemory	Standalone runner never initializes its memory manager; retain the working dictionary capacity/overflow benchmark.
BenchmarkQueryEngine	Hard-coded data-directory/table template with only COUNT and no teardown; use the configurable driver or current SSQE/MSQE workloads.
BenchmarkRoaringBitmapCreation	Measures benchmark-local copies of retired SoftReference cache implementations rather than the current index reader.
BenchmarkRoaringBitmapMapping	Requires external, unprovided fixtures and compares algorithms that discard different trailing results.
BenchmarkJsonKeyMap	Retired map/concatenation experiment; one variant fills a different map from the one it clears and returns.
BenchmarkGroovyExpressionEvaluation	Generic Java/Groovy comparison bypasses Pinot's evaluator, times input generation, and discards results.

Keep benchmarks for current query, index, dictionary, aggregation, JSON/MAP, ingestion, resource-accounting, and vector paths, including meaningful implementation and algorithm baselines. The removed experiments do not all have one-to-one replacements; current workload coverage remains.

Unit-test cleanup

• Remove those two timing-only tests and their unused helper code, plus the three disabled methods in VectorSearchBenchmark.
• Preserve the HDFS batch-deletion assertions while removing its elapsed-time threshold.
• Rename the ten-value ANY_VALUE test to describe its correctness coverage, and make the interner helper always assert equality.

The remaining correctness-test datasets and assertions are unchanged.

How to reproduce

On the base revision, run the interner benchmark through the normal unit-test runner:

./mvnw -pl pinot-common -am \
  '-Dtest=FALFInternerTest#benchmarkingTest' \
  -Dsurefire.failIfNoSpecifiedTests=false test

The selected method repeatedly interns values and prints timings without checking correctness. The cleanup removes that method while retaining testInterningByteBuffers and its assertions. The retention benchmark similarly checks only a 30-second threshold; existing retention tests continue to verify tracked-segment exclusion and deletion candidates.

Validation

Using JDK 25, 136 focused tests passed with no failures, errors, or skips:

./mvnw -pl pinot-common,pinot-core,pinot-controller,pinot-segment-local,pinot-plugins/pinot-file-system/pinot-hdfs -am \
  -Dtest=FALFInternerTest,RetentionManagerTest,AnyValueAggregationFunctionTest,HadoopPinotFSTest,IvfFlatVectorIndexTest,IvfFlatFilterAwareTest,ScalarQuantizerTest \
  -Dsurefire.failIfNoSpecifiedTests=false test

Spotless, Checkstyle, license formatting, and license validation passed for all five affected modules. Isolated javac -Xlint:all checks passed for all four modified test classes with no warnings on added lines. The additional reactor build with expanded deprecation checking hit the existing missing JetBrains NotNull annotation dependency in unchanged ZstandardDecompressor; the normal reactor build and tests passed.

For the benchmark module, all four style/license checks passed. The complete 64-module reactor package build passed:

./mvnw -pl pinot-perf -am -Ppinot-fastdev -DskipTests package

JMH discovery from the generated package lists 302 retained benchmark methods; removed benchmarks are absent. All 16 generated launcher scripts reference existing classes, and the five retired launchers are absent.

Forked smoke runs passed for the retained SUM and dictionary-lookup workloads. These runs validate execution only:

java @.mvn/jvm.config -cp 'pinot-perf/target/pinot-perf-pkg/lib/*' org.openjdk.jmh.Main \
  'SumIntAggregationFunctionBenchmark.testSumAggregation$' \
  -p _nullHandling=false -p _nullPeriod=16 -f 1 -wi 0 -i 1 -r 100ms -foe true
java @.mvn/jvm.config -cp 'pinot-perf/target/pinot-perf-pkg/lib/*' org.openjdk.jmh.Main \
  'BenchmarkDictionaryLookup.benchmarkPlainBinarySearch$' \
  -p _cardinality=100 -p _lookupPercentage=100 -f 1 -wi 0 -i 1 -r 100ms -foe true

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 67.73%. Comparing base (5771d6a) to head (92c10a6).

Additional details and impacted files

@@             Coverage Diff              @@
##             master   #19538      +/-   ##
============================================
+ Coverage     67.72%   67.73%   +0.01%     
  Complexity     1450     1450              
============================================
  Files          3490     3490              
  Lines        225032   225032              
  Branches      35527    35527              
============================================
+ Hits         152393   152418      +25     
+ Misses        60612    60580      -32     
- Partials      12027    12034       +7     

Flag	Coverage Δ
integration	100.00% <ø> (ø)
integration1	100.00% <ø> (ø)
integration2	0.00% <ø> (ø)
java-25	67.73% <ø> (+0.01%)	⬆️
lane-a	100.00% <ø> (ø)
lane-b	0.00% <ø> (ø)
temurin	67.73% <ø> (+0.01%)	⬆️
unittests	67.72% <ø> (+0.01%)	⬆️
unittests1	57.82% <ø> (+0.01%)	⬆️
unittests2	39.49% <ø> (+<0.01%)	⬆️

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