prometheus/prometheus v3.5.0 Release Notes

Published at: 2025-07-14T16:54:21Z

3.5 is a Long Term Support (LTS) release; see release https://prometheus.io/docs/introduction/release-cycle/ There are a number of new features, and no known breaking changes in this release:

[FEATURE] PromQL: Add experimental type and unit metadata labels, behind feature flag type-and-unit-labels. #16228 #16632 #16718 #16743
[FEATURE] PromQL: Add ts_of_(min|max|last)_over_time, behind feature flag experimental-promql-functions. #16722 #16733
[FEATURE] Scraping: Add global option always_scrape_classic_histograms to scrape a classic histogram even if it is also exposed as native. #16452
[FEATURE] OTLP: New config options promote_all_resource_attributes and ignore_resource_attributes. #16426
[FEATURE] Discovery: New service discovery for STACKIT Cloud. #16401
[ENHANCEMENT] Hetzner SD: Add label_selector to filter servers. #16512
[ENHANCEMENT] PromQL: support non-constant parameter in aggregations like quantile and topk. #16404
[ENHANCEMENT] UI: Better total target count display when using keep_dropped_targets option. #16604
[ENHANCEMENT] UI: Add simple filtering on the /rules page. #16605
[ENHANCEMENT] UI: Display query stats in hover tooltip over table query tab. #16723
[ENHANCEMENT] UI: Clear search field on /targets page. #16567
[ENHANCEMENT] Rules: Check that rules parse without error earlier at startup. #16601
[ENHANCEMENT] Promtool: Optional fuzzy float64 comparison in rules unittests. #16395
[PERF] PromQL: Reuse histogramStatsIterator where possible. #16686
[PERF] PromQL: Reuse storage for custom bucket values for native histograms. #16565
[PERF] UI: Optimize memoization and search debouncing on /targets page. #16589
[PERF] UI: Fix full-page re-rendering when opening status nav menu. #16590
[PERF] Kubernetes SD: use service cache.Indexer to achieve better performance. #16365
[PERF] TSDB: Optionally use Direct IO for chunks writing. #15365
[PERF] TSDB: When fetching label values, stop work earlier if the limit is reached. #16158
[PERF] Labels: Simpler/faster stringlabels encoding. #16069
[PERF] Scraping: Reload scrape pools concurrently. #16595 #16783
[BUGFIX] Top-level: Update GOGC before loading TSDB. #16491
[BUGFIX] Config: Respect GOGC environment variable if no “runtime” block exists. #16558
[BUGFIX] PromQL: Fix native histogram last_over_time. #16744
[BUGFIX] PromQL: Fix reported parser position range in errors for aggregations wrapped in ParenExpr #16041 #16754
[BUGFIX] PromQL: Don’t emit a value from histogram_fraction or histogram_quantile if classic and native histograms are present at the same timestamp. #16552
[BUGFIX] PromQL: Incorrect rounding of [1001ms] to [1s] and similar. #16478
[BUGFIX] PromQL: Fix inconsistent / sometimes negative histogram_count and histogram_sum. #16682
[BUGFIX] PromQL: Improve handling of NaNs in native histograms. #16724
[BUGFIX] PromQL: Fix unary operator precedence in duration expressions. #16713
[BUGFIX] PromQL: Improve consistency of avg aggregation and avg_over_time. #16569 #16773
[BUGFIX] UI: Add query warnings and info to graph view. #16753 #16759
[BUGFIX] API: Add HTTP Vary: Origin header to responses to avoid cache poisoning. #16008
[BUGFIX] Discovery: Avoid deadlocks by taking locks in consistent order. #16587
[BUGFIX] Remote-write: For Azure AD auth, allow empty client_id to suppport system assigned managed identity. #16421
[BUGFIX] Scraping: Fix rare memory corruption bug. #16623
[BUGFIX] Scraping: continue handling custom-bucket histograms after an exponential histogram is encountered. #16720
[BUGFIX] OTLP: Default config not respected when otlp: block is unset. #16693

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