geonove opened a new issue, #457: URL: https://github.com/apache/datasketches-cpp/issues/457
## Proposal: Add DDSketch (Relative-Error Quantile Sketch) **Summary:** This issue proposes adding an implementation of [DDSketch](https://www.vldb.org/pvldb/vol12/p2195-masson.pdf), a mergeable quantile sketch with relative-error guarantees, to the `datasketches-cpp` library. ## Motivation Current quantile sketches in `datasketches-cpp` (KLL, REQ, t-digest) offer absolute-error guarantees. DDSketch fills a different use case: relative-error quantiles, which are more appropriate for latency percentiles and metrics with a wide dynamic range. Benefits: - Relative-error guarantees - Mergeability for distributed processing - Predictable memory usage - Used in production (Datadog, OpenTelemetry) ## References - VLDB 2019: [DDSketch Paper](https://www.vldb.org/pvldb/vol12/p2195-masson.pdf) - [Datadog's sketches-java repo](https://github.com/DataDog/sketches-java) ## Proposed Design - New class under `ddsketch.hpp` - Logarithmic mapping of input values to buckets using configurable relative accuracy - Compact, bounded memory footprint with optional bucket collapsing - Mergeable histogram-style structure - Serialization and deserialization support - Unit tests and benchmarks included ## Compatibility - No changes to existing APIs - Implementation will be self-contained - Optional: initial release could be marked experimental ## Next Steps If there is community interest, I’m happy to: 1. Share a detailed design document 2. Begin work on the implementation and submit a PR 3. Iterate based on feedback Would the maintainers be open to including DDSketch? Are there specific design or compatibility considerations I should address before proceeding? Thanks, Andrea Novellini (@geonove) -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
