perf(metric-engine)!: Replace mur3 with fxhash for faster TSID generation #7316
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perf(metric-engine): replace mur3 with fxhash for faster TSID generation - Switches from mur3::Hasher128 to fxhash::FxHasher for TSID hashing - Pre-computes label-name hash when no nulls are present, avoiding redundant work - Adds fast-path for rows without nulls; falls back to slow path otherwise - Updates Cargo.toml and lockfile to reflect dependency change Signed-off-by: Lei, HUANG <[email protected]>
fix: only check primary-key labels for null when re-using cached hash - Rename has_null() → has_null_labels() and restrict the check to the primary-key columns so that non-label NULLs do not force a full TSID re-computation. - Update expected hashes in tests to match the new logic. Signed-off-by: Lei, HUANG <[email protected]>
test: add comprehensive TSID generation tests for label ordering and null handling Signed-off-by: Lei, HUANG <[email protected]>
bench: add criterion benchmark for TSID generator - Compare original mur3 vs current fxhash fast/slow paths - Test 2, 5, 10 label sets plus null-value slow path - Add mur3 & criterion dev-deps; register bench target Signed-off-by: Lei, HUANG <[email protected]>
test: stabilize metric-engine tests by fixing non-deterministic row order - Add ORDER BY to SELECTs in TTL tests to ensure consistent output - Update expected __tsid values after hash function change - Swap expected OTLP metric rows to match new ordering Signed-off-by: Lei, HUANG <[email protected]>
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refactor: simplify Default impls and remove redundant code - Replace manual Default for TsidGenerator with derive - Remove unnecessary into_iter() call - Simplify Option::unwrap_or_else to unwrap_or Signed-off-by: Lei, HUANG <[email protected]>
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Copilot finished reviewing on behalf of
WenyXu
December 2, 2025 04:33
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Pull request overview
This PR replaces the mur3::Hasher128 with fxhash::FxHasher for TSID (Time Series ID) generation in the metric engine, achieving 5-6x performance improvement through both a faster hash algorithm and a smart fast-path optimization. The change is breaking as TSID values will differ, requiring comprehensive test updates to reflect new hash outputs and ensure deterministic ordering.
Key changes:
- Migrated from 128-bit mur3 hash to 64-bit fxhash for TSID generation
- Introduced fast-path optimization that pre-computes label name hashes when no nulls are present
- Added comprehensive test coverage for TSID generation edge cases and invariants
- Updated all affected tests with ORDER BY clauses and new expected TSID values
Reviewed changes
Copilot reviewed 11 out of 12 changed files in this pull request and generated 2 comments.
Show a summary per file
| File | Description |
|---|---|
src/metric-engine/src/row_modifier.rs |
Core implementation: replaced mur3::Hasher128 with fxhash::FxHasher, added fast/slow path logic, pre-computes label name hash in IterIndex, added comprehensive unit tests for TSID generation invariants |
src/metric-engine/benches/bench_tsid_generator.rs |
New benchmark suite comparing original mur3 vs current fxhash implementation across different label counts and null-handling scenarios |
src/metric-engine/src/engine/put.rs |
Updated test expectations with new TSID values resulting from hash algorithm change |
src/metric-engine/Cargo.toml |
Added fxhash dependency, moved mur3 to dev-dependencies for benchmarking, added benchmark configuration |
Cargo.lock |
Dependency lock file updates for fxhash and criterion additions |
tests/cases/standalone/common/ttl/metric_engine_ttl.sql |
Added ORDER BY clauses to queries for deterministic result ordering |
tests/cases/standalone/common/ttl/metric_engine_ttl.result |
Updated expected results with correct ordering and new TSID values |
tests/cases/standalone/common/ttl/database_ttl_with_metric_engine.sql |
Added ORDER BY clauses to queries for deterministic result ordering |
tests/cases/standalone/common/ttl/database_ttl_with_metric_engine.result |
Updated expected results with correct ordering and new TSID values |
tests/cases/standalone/common/insert/logical_metric_table.result |
Updated expected TSID values and result ordering to reflect new hash algorithm |
tests-integration/tests/region_migration.rs |
Added ORDER BY clauses to test queries for deterministic results |
tests-integration/tests/http.rs |
Updated expected result ordering in HTTP endpoint tests |
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WenyXu
approved these changes
Dec 2, 2025
evenyag
approved these changes
Dec 2, 2025
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What's changed and what's your intention?
Summary
This PR optimizes TSID (Time Series ID) generation in the metric engine by replacing
mur3::Hasher128withfxhash::FxHasherand introducing a fast-path optimization for rows without null values. The changes result in 5-6x performance improvement for typical use cases.Changes
Hash Algorithm Migration
mur3::Hasher128withfxhash::FxHasherfor TSID hashingmur3dependency, addedfxhashdependencyFast-Path Optimization
Performance Benchmarks
Performance Results
Benchmark results show significant performance improvements:
Technical Details
Fast Path Implementation
When a row has no null label values, the implementation:
Slow Path Implementation
When null values are detected:
Breaking Changes
PR Checklist
Please convert it to a draft if some of the following conditions are not met.