tag

#promql

4 posts

SRE & DevOpsDeep Dive October 13, 2026 7 min read

Prometheus Staleness Semantics: Lookback, Disappearing Series, and Query-Time Evidence

Understand how Prometheus instant selectors, stale series, lookback, and absence functions affect dashboards and alerts without mistaking missing data for zero.

#prometheus#promql#observability

SRE & DevOpsDeep Dive October 3, 2026 6 min read

Prometheus Alert Rules: Evaluation, Pending State, and Notification Boundaries

Understand Prometheus rule-group timing, `for`, `keep_firing_for`, alert identity, missing data, and the separate Alertmanager delivery path.

#prometheus#alerting#promql

SRE & DevOpsDeep Dive October 3, 2026 8 min read

Prometheus Rule Tests: promtool Fixtures and Alert Coverage

Test PromQL and alert-rule behavior deterministically with promtool, including pending intervals, labels, missing series, group order, and CI validation.

#prometheus#promql#alerting

SRE & DevOpsDeep Dive August 27, 2026 6 min read

Prometheus Native Histograms: Sparse Buckets, Mergeable Resolution, and Migration

How native histograms store a distribution in one structured sample, how PromQL aggregates it, and how to migrate without breaking dashboards or remote write.

#prometheus#histograms#promql