Terms used by the cost-based sketch optimizer and its benchmarking pipeline.
Grouping labels:
PromQL GROUP BY labels that partition a metric stream into label groups; a
non-subpopulation sketch is instantiated once per distinct group.
Avoid: keying labels
Sketch key: The value or label tuple inserted into and queried from a keyed sketch such as HLL, CMS, or Hydra. Its distribution, cardinality, and encoded size may affect the measured atomic cost and accuracy. Avoid: grouping label, partition key
Benchmark profile: A reproducible description of the input trace slice used to measure an atomic-cost table for a sketch family and configuration.
Planner context: Query- and deployment-specific structural inputs, such as label-group count and retained-window count, that scale atomic costs into a plan cost.