chore(k305): release 3.8.0

[loki-gh-app]

🤖 I have created a release beep boop

3.8.0

3.8.0 (2026-05-04)

⚠ BREAKING CHANGES

• Remove support for BigTable/GCP storage backend (#21502)
• Remove deprecated Cassandra storage backend (#21574)
• Remove deprecated DynamoDB storage backend (#21601)
• Remove deprecated gRPC storage backend (#21638)
• Remove deprecated BoltDB storage backend for indexes (#21637)
• ksonnet: Remove boltdb-shipper specific flags from lib (#21656)

Features

• Add a metric that reports when goldfish racing is enabled (#21376) (b48a70c)
• Add caching node to dataobjscan node (#21246) (9ed2dd0)
• add metric loki_distributor_dataobj_tee_estimate_rate_bytes (#21441) (cae9486)
• add per-phase histogram metrics to engine worker pipeline (#21547) (c0a243b)
• add stats and postings index sections with encoding abstraction (#21442) (8553815)
• add time sharded estimate (#21463) (47e1e81)
• Avoid executing tasks for which we have cached empty results (#21437) (fb6abe5)
• Batch cache fetches in schedulers during task pruning (#21548) (f367374)
• ci: Include linux/riscv64 Loki build in releases (#21597) (76e65d7)
• clamp pointerscans to index start/end timeranges (#21534) (2e0a70d)
• dataobj-inspect: support more section types (#21269) (286bca7)
• dataobj: Add sort_schema config and feature flag (#21460) (30549ac)
• default loki-mixin dashboards to TSDB (#18732) (d5fa6f7)
• fluentd: bump version (#21337) (33fdfa1)
• handle context cancelation in memcached batching (#21625) (abc30f5)
• helm: Update charts for GEL (#21590) (733fb71)
• Introduce max-age option for index-builder (#21294) (4772bfc)
• lokitool: Rename rules lint to rules format (#21671) (01f2177)
• more accurate counts of max_inflight_bytes (#21611) (4965669)
• operator: migrate to thanos objstore backend (#20475) (ffcac2c)
• otlp: add event_name to OTLP log structured metadata (#21229) (c9a1785)
• query engine: Add workflow optimizer to clamp predicates on scan nodes (#21327) (4e187b1)
• query engine: Implement line_format and label_format with new engine (#20123) (7be7c9d)
• querytee: route v2-unsupported request types directly to v1 in SplittingHandler (#21450) (4515b4b)
• Remove Promtail support (#21245) (572df01)
• Remove task_pruning_cache_fetch_batch_size in favor of existing memcached batching (#21593) (24ca0e4)
• Resolve cached tasks in parent task (#21558) (904c963)
• return caching stats in new engine (#21369) (c32b57f)
• Use AppendOrdered strategy to avoid sorting and merging stripes (#21395) (bd7530f)
• use query logger on metastore workflow (#21511) (b68de56)
• WIP: Task level caching (#21160) (bd51fca)

Bug Fixes

• allow S3 test to pass regardless of AWS config (#21499) (5fda167)
• Bloom index gateway skipping chunks with 1 log line (#21237) (067d55d)
• Bump release please version. (#21319) (91e355e)
• clarify retention cutoff timestamp in compactor log (#21119) (581a9fd)
• columnar: Copy label values to avoid retaining memory (#21594) (8ca16c4)
• columnar: Don't release Arrow records (#21670) (9cdc29f)
• columnar: Fix two race conditions in pkg/engine (#21674) (4850f1b)
• compactor: prevent FD leak on partial compaction failure (#20913) (2b5d26d)
• correct Makefile issues (#21654) (6f6e86a)
• deps: update github.com/prometheus/prometheus digest to 9670de1 (main) (#21215) (2be356f)
• deps: update module charm.land/bubbles/v2 to v2.1.0 (main) (#21303) (8348756)
• deps: update module charm.land/bubbletea/v2 to v2.0.5 (main) (#21585) (9ead25b)
• deps: update module charm.land/bubbletea/v2 to v2.0.6 (main) (#21616) (ac49d83)
• deps: update module charm.land/lipgloss/v2 to v2.0.3 (main) (#21587) (573f5fe)
• deps: update module cloud.google.com/go/bigtable to v1.45.0 (main) (#21383) (62ecd74)
• deps: update module cloud.google.com/go/pubsub/v2 to v2.5.0 (main) (#21231) (66b7c06)
• deps: update module cloud.google.com/go/storage to v1.62.1 (main) (#21493) (289cf2b)
• deps: update module github.com/apache/cassandra-gocql-driver/v2 to v2.1.0 (main) (#21377) (e5e7e48)
• deps: update module github.com/aws/aws-sdk-go-v2/config to v1.32.14 (main) (#21315) (cbf0444)
• deps: Update module github.com/aws/aws-sdk-go-v2/config to v1.32.16 (main) (#21618) (b14e5b2)
• deps: update module github.com/aws/aws-sdk-go-v2/credentials to v1.19.15 (main) (#21634) (19f8688)
• deps: update module github.com/aws/aws-sdk-go-v2/service/dynamodb to v1.57.1 (main) (#21235) (dc15bfb)
• deps: update module github.com/aws/aws-sdk-go-v2/service/s3 to v1.98.0 (main) (#21283) (835fff4)
• deps: update module github.com/aws/aws-sdk-go-v2/service/s3 to v1.99.1 (main) (#21521) (13e2a5a)
• deps: update module github.com/aws/smithy-go to v1.24.3 (main) (#21416) (5ec9b00)
• deps: update module github.com/aws/smithy-go to v1.25.0 (main) (#21613) (88690fe)
• deps: update module github.com/baidubce/bce-sdk-go to v0.9.263 (main) (#21326) (6d2923b)
• deps: update module github.com/baidubce/bce-sdk-go to v0.9.264 (main) (#21513) (ad2a80e)
• deps: update module github.com/baidubce/bce-sdk-go to v0.9.265 (main) (#21629) (eb67f6d)
• deps: update module github.com/coder/quartz to v0.3.1 (main) (#21529) (c7455ae)
• deps: update module github.com/fatih/color to v1.19.0 (main) (#21234) (6769e67)
• deps: update module github.com/grafana/loki/pkg/push to v0.4.0 (main) (#21640) (0a0078d)
• deps: update module github.com/klauspost/compress to v1.18.5 (main) (#21226) (74d36e9)
• deps: update module github.com/minio/minio-go/v7 to v7.0.100 (main) (#21375) (edb6f56)
• deps: update module github.com/shirou/gopsutil/v4 to v4.26.3 (main) (#21350) (a2bc46e)
• deps: update module github.com/tjhop/slog-gokit to v0.2.0 (main) (#21565) (5ff0204)
• deps: update module github.com/twmb/franz-go/pkg/kmsg to v1.13.1 (main) (#21446) (c9417c4)
• deps: update module go.opentelemetry.io/collector/pdata to v1.54.0 (main) (#21216) (5f4b4ab)
• deps: update module go.opentelemetry.io/collector/pdata to v1.55.0 (main) (#21392) (afebbf7)
• deps: update module go.opentelemetry.io/collector/pdata to v1.56.0 (main) (#21572) (8fa464e)
• deps: update module go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc to v0.67.0 (main) (#21072) (07bd5dc)
• deps: update module go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc to v0.68.0 (main) (#21505) (8f24087)
• deps: update module go.opentelemetry.io/contrib/instrumentation/net/http/httptrace/otelhttptrace to v0.68.0 (main) (#21506) (c21805a)
• deps: update module go.opentelemetry.io/otel to v1.43.0 (main) (#21418) (148ec88)
• deps: update module go.opentelemetry.io/otel/sdk to v1.43.0 (main) (#21419) (e4c0bf6)
• deps: update module go.opentelemetry.io/otel/trace to v1.43.0 (main) (#21420) (08e2dac)
• deps: update module golang.org/x/tools to v0.44.0 (main) (#21532) (7e6feef)
• deps: update module google.golang.org/api to v0.273.0 (main) (#21309) (d403344)
• deps: update module google.golang.org/api to v0.274.0 (main) (#21408) (a90a776)
• deps: update module google.golang.org/api to v0.275.0 (main) (#21514) (8b3b432)
• deps: update module google.golang.org/api to v0.276.0 (main) (#21606) (8d0ef72)
• deps: update module google.golang.org/grpc to v1.79.3 [security] (main) (#21192) (606472c)
• deps: update module google.golang.org/grpc to v1.80.0 (main) (#21409) (7adda86)
• deps: update module k8s.io/apimachinery to v0.35.4 (main) (#21600) (b663ffb)
• do not spawn workers if ingesters are disabled (#21539) (0f29990)
• Fix assignment to entry in nil map in DataobjSectionDescriptor.Merge (#21268) (bb48b9c)
• Fix MatchNotRegexp misbehaving with the new query engine (#21544) (bb55364)
• Fix ruler panic related to unset validation scheme (#21400) (a5bd996)
• fluentd: support certificate chain files in mTLS client config (#21296) (e6ca622)
• grouping by non-existent label in v2 query engine (#21430) (e74e2a2)
• handle INIT from frontend in running scheduler which is not in shouldRun state (#19866) (6f81a0c)
• ibmcloud: prevent IsObjectNotFoundErr from crashing (#20668) (dce323d)
• Incorrect impl of ProduceSync (#21702) (9a9ba8d)
• index-builder: don't repeatedly build indexes for stale partitions (#21213) (4725e2b)
• logfmt: use debug logging instead of error similar to what json plugin does (#20885) (c10cc90)
• logql: Fix nil pointer dereference caused by data race during query blocking (#21726) (ed28b61)
• lokitool: correct rule-files help text for rules lint (#21592) (5f896b3)
• make the chunkFilter apply to new MultiIndex/s (#21187) (444462c)
• memory: fix off-by-one in Bitmap.Slice for byte-aligned ends (#21354) (93650c0)
• nix: update flake.lock (#21353) (567b579)
• operator: Fix RemoteWriteAuthType CEL validation in RulerConfig (#21677) (50e5873)
• operator: Replace local pkg/push dependency with published module (#21679) (752874f)
• operator: tidy go.mod (#21323) (119622b)
• operator: update latency alert to reflect ingester timeout (#21370) (91f0ce4)
• otel: update dskit version (#21343) (b1c6ac2)
• Preserve caching options after query split (#21320) (9bafc1e)
• preserve parsed labels with empty values in samples query response from thor engine (#21351) (399efb0)
• protobuf decoding for DetectedLabelsRequest (#21223) (277e439)
• querier: Add HTTP headers to volume response (#21598) (e10b92f)
• query-engine: Fix different error messages ending up in different streams (#21552) (f4f4bce)
• remove all unrelated AWS env vars from storage test (#21533) (98ab633)
• restore pipe '|' as a word boundary in level detection (#21428) (234da0c)
• restore single quote as word boundary in level detection (#21429) (7a6870c)
• return error for query parameter integer overflow (#21389) (928fec3)
• Revert "fix(deps): update module github.com/grafana/loki/pkg/push to v0.4.0 (main)" (#21666) (f5d391e)
• ruler: Fix broken structured logging for insight logs (#21728) (5fb2f48)
• ruler: Skip dotfiles when listing local rule files (#21519) (99c0b02)
• storage: attach SHA-256 checksum on PutObject for Object Lock buckets (#21649) (c83d748)
• storage: Respect AZURE_AUTHORITY_HOST environment variable in servicePrincipalTokenFromFederatedToken (#21554) (e923183)
• storage: Use correct protocol and suffix from Azure connection string for SAS URLs (#21555) (e98653f)
• the "empty ring" error in quick-start guide for docker-compose.yaml (#18006) (6c4807e)
• tsdb: delete empty streams from builder map in ToIndexFile (#21312) (744b04f)
• Use KafkaWriter in dataobj-tee (#21732) (d8f4d0f)
• Use newer Go in fluentbit and fix canary test (#21254) (0cfd943)
• Wire up default gRPC client config to ruler's query-frontend clients (#21549) (43d0784)

Performance Improvements

• avoid unnecessary shuffle sharding (#21344) (34e5cc9)
• blooms: return full slice to pool after use (#20981) (9d9c7af)
• short-circuit cache when over max cacheable size (#21277) (5f06abe)
• support shuffle shard by tenant to increase cache hits (#21357) (787276e)

Miscellaneous Chores

• ksonnet: Remove boltdb-shipper specific flags from lib (#21656) (6446e91)
• Remove deprecated BoltDB storage backend for indexes (#21637) (7bd0ca3)
• Remove deprecated Cassandra storage backend (#21574) (7c64707)
• Remove deprecated DynamoDB storage backend (#21601) (67bf1e6)
• Remove deprecated gRPC storage backend (#21638) (5291b3f)
• Remove support for BigTable/GCP storage backend (#21502) (1846a8f)

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Merging this PR will release the artifacts of d8f4d0f

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Note

Low Risk
Release bookkeeping only: updates version manifest and CHANGELOG.md without changing product code paths. Main risk is downstream consumers relying on deprecated backends called out as breaking changes in the notes.

Overview
Publishes the 3.8.0 release by updating .release-please-manifest.json and adding the 3.8.0 section to CHANGELOG.md (including the listed breaking changes, features, fixes, and perf notes).

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