issue-link js-issue-link" data-error-text="Failed to load title" data-id="2362930846" data-permission-text="Title is private" data-url="https://github.com/open-telemetry/opentelemetry-collector-contrib/issues/33661" data-hovercard-type="issue" data-hovercard-url="/open-telemetry/opentelemetry-collector-contrib/issues/33661/hovercard" href="https://github.com/open-telemetry/opentelemetry-collector-contrib/issues/33661">open-telemetry#33661 is still open; the prior attempt (open-telemetry#42606) was abandoned, closed unmerged over merge conflicts and self-described as "not fully implemented and ready for use." This is a fresh implementation rather than a revival of open-telemetry#42606, and differs on three points that matter for us: 1. Both write paths. open-telemetry#42606 only converted on the RW2 (writev2) path; the RW1 path it left untouched is the one our pipeline uses (protobuf_message: prometheus.WriteRequest). Here a shared helper feeds both RW1 and RW2. 2. Canonical encoding. open-telemetry#42606 hand-rolled span/delta encoding by repurposing the exponential-histogram layout code. This reuses Prometheus' own util/convertnhcb, so the wire output matches a server-side scrape conversion exactly and inherits its edge-case handling. 3. Dual-write. open-telemetry#42606 emitted NHCB instead of classic. keep_classic_histograms emits both at once, which is what makes migration safe: move dashboards and alerts to the native form on your own schedule while classic keeps flowing, roll back instantly, then drop classic to reclaim the cardinality. `convert_histograms_to_nhcb` produces NHCB (schema -53); `keep_classic_histograms` keeps the classic series alongside. Default-off, exposed as exporter config (unlike open-telemetry#42606's translator-only flag). See the chloggen entry and code comments for the user-facing summary and mechanics. Tests cover both paths: bucket-count round-trip, no-sum, no-bounds, stale markers, exemplars, dual-emit, classic-default, and conversion-error handling.

Commits

Commits on Jun 11, 2026

[exporter/prometheusremotewrite] Add classic→NHCB conversion with dual-write

Avoid negative buckets in translated histograms

Commits on Jun 16, 2026

Merge branch 'main' into sstrickland/nhcb-conversion

Fix lint and regenerate config schema