IFO4
Loading...The exponential growth in stored time series, log indexes, or event partitions caused by labelling decisions that include high-cardinality attributes such as user identifiers, request paths with parameters, or random hashes. Cardinality explosion is both a cost problem and a query performance problem. The federation requires cardinality budgets per service with a documented owner, an alerting threshold, and a remediation playbook. Sustained cardinality breaches are reported as observability waste under UFMS-001:2.4(e) and remediated through label hygiene reviews.
A compound of cardinality, from medieval Latin cardinalis, principal, used in mathematics for set size, and explosion, from Latin explodere; the IT sense was settled by the Prometheus literature of the late 2010s.
Federation members publish cardinality budgets per service and report breaches in the FinOps inform report. Sustained breaches are remediated through label hygiene reviews under MEV-Annex:3.2. Cardinality controls are part of the observability maturity assessment.
@misc{ifo4_glossary_cardinality_explosion,
title = {{Cardinality Explosion}},
author = {{IFO4 Federation Editorial Board}},
howpublished = {{IFO4 Federation Glossary, slug \texttt{cardinality-explosion}}},
year = {2026},
url = {https://ifo4.org/glossary/cardinality-explosion},
note = {Category: Waste; key: CardinalityExplosion}
}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.