IFO4
Loading...The count of distinct values for a dimension, or for a combination of dimensions, in a metric or log series. Cardinality is the principal cost driver of observability backends: storage, query latency, and ingestion expense scale with the product of cardinalities across dimensions. The federation treats cardinality as a budgeted resource: each Tier-1 service must declare a cardinality envelope, and dimensions exceeding the envelope must be sampled, hashed, or removed. Uncontrolled cardinality is reported as an observability finding under UFMS-001:2.4.
Set-theory term in continuous use since the late nineteenth century; carried into observability through the database-engineering vocabulary of the 2010s.
Federation members must publish cardinality envelopes for each Tier-1 service and report breaches monthly. Persistent breach without remediation is reported under MEV-Annex:3.2.
@misc{ifo4_glossary_cardinality,
title = {{Cardinality}},
author = {{IFO4 Federation Editorial Board}},
howpublished = {{IFO4 Federation Glossary, slug \texttt{cardinality}}},
year = {2026},
url = {https://ifo4.org/glossary/cardinality},
note = {Category: Observability; key: Cardinality}
}Federation members and accredited practitioners may challenge any entry under TGS-002:1.7. Filed challenges are routed to the editorial board, triaged into the revision register, and resolved in writing on the public docket. The slug remains stable through any revision.