grafana/loki v4.0.0-rc.2 on GitHub

See CHANGELOG.md for the full list of changes.

4.0.0-rc.2 (2026-11-04)

Reverts

Disable Multipath TCP on listeners by default (#26237) (7637697)

4.0.0-rc.1 (2026-11-03)

⚠ BREAKING CHANGES

Upgrade Go module to github.com/grafana/loki/v4 (#25972)
querytee: Configure a primary and a secondary backend (#25552)
querytee: Remove the request splitting (#25496)
engine: Unplug the V2 query engine from the config and modules (#25353)
querytee: Remove the routing modes (#25487)
Rename remaining loki_boltdb_shipper_* metrics to loki_tsdb_shipper_* (#25345)
operator: Stop reconciliation of deprecated BoltDB schemas (#24990)
logql: Stop writing preserve_error as a label (#24877)
operator: Make schemas field required in storage spec (#24716)
logql: Let an error filter decide whether a metric query keeps errored samples (#24719)
logql: Apply grouping to an errored sample's labels (#24712)
Remove deprecated ruler_remote_write_* per-tenant limits (#22941)
frontend: Default frontend.encoding to protobuf (#23985)
Remove support for experimental LogQL variants() queries (#23823)
Remove row_shards from the schema configuration (#23683)
Remove the disable_broad_index_queries setting (#23679)
Remove unused period_config settings that are no longer used by TSDB index (#23665)
ruler: Remove deprecated remote-write 'client' setting (#23453)
Remove deprecated per_tenant_override_config and per_tenant_override_period (#22856)
ruler: Always wipe the remote-write WAL on startup (#22509)
storage: Use Thanos storage clients by default (#22676)
Remove targets for Simple Scalable Deployment (SSD) (#21481)
Remove index read cache and index cache validity settings (#22066)
Remove deprecated write dedupe cache (#22056)
Remove deprecated BoltDB Shipper storage backend (#21678)
Remove deprecated per-tenant setting unordered_writes (#21835)
Remove deprecated allow_deletes configuration option (#21808)
Rename metric loki_log_flushes (#21765)
Remove deprecated loki_log_messages_total metric (#21764)
ksonnet: Remove boltdb-shipper specific flags from lib (#21656)
Remove deprecated BoltDB storage backend for indexes (#21637)
Remove deprecated gRPC storage backend (#21638)
Remove deprecated DynamoDB storage backend (#21601)
Remove deprecated Cassandra storage backend (#21574)
Remove support for BigTable/GCP storage backend (#21502)

Features

Add a gauge for the max inflight bytes limit (#24209) (110923a)
Add a metric that reports when goldfish racing is enabled (#21376) (b48a70c)
Add a minimum number of shuffle shard size in index gateway client (#22573) (7d69c1c)
Add caching node to dataobjscan node (#21246) (9ed2dd0)
Add circuit breaker to drop traffic (#23157) (f9ed564)
Add flag to ignore missing chunks during deletion of logs with line filter (#24204) (22b28a7)
Add label based access control LBAC (#21266) (976379a)
Add limit for max inflight bytes (#23188) (7a5c93d)
Add limit on max buffered bytes in pattern-tee (#21855) (8c6c2ab)
add metric loki_distributor_dataobj_tee_estimate_rate_bytes (#21441) (cae9486)
Add more details to failed query usage logs (#25616) (b21487a)
Add per tenant max push size override (#24194) (443c975)
add per-phase histogram metrics to engine worker pipeline (#21547) (c0a243b)
Add policy to limits service and ratestore metrics (#25182) (16149f6)
Add q param to /config for scoped field access (#24230) (b645ac3)
add stats and postings index sections with encoding abstraction (#21442) (8553815)
Add support for otlp protocol to canary for continuous testing of otlp ingestion (#24985) (6abd850)
Add support for sharding nested streams by rate and time (#24476) (a832813)
add time sharded estimate (#21463) (47e1e81)
Add X-Loki-Backfill-Day header to label backfilled streams (#22628) (bb93c60)
alibaba oss: Alibaba oss ecs ram role (#21989) (5555ff9)
Align loki_querier_worker_inflight_queries metric betweek Frontend v1 and v2 (#23452) (48444ab)
Allow overriding rate limits per ingestion policy (#22435) (bd7c05d)
auth: Add no_auth_tenant config option for single-tenant mode (#21819) (7923fe1)
Avoid executing tasks for which we have cached empty results (#21437) (fb6abe5)
Batch cache fetches in schedulers during task pruning (#21548) (f367374)
canary: Implement support for path prefixes (#24534) (a8b5c92)
ci: Include linux/riscv64 Loki build in releases (#21597) (76e65d7)
clamp pointerscans to index start/end timeranges (#21534) (2e0a70d)
Collapse max request body size and decompressed size (#24076) (3dc5a8e)
compaction: Build index over compacted log objects in LogMerge (#23214) (eb93257)
compaction: Compact a configurable lookback of older windows (#23411) (4d0120c)
compaction: Implement merge for log objects (#23117) (b88aca5)
compaction: Log object compaction - contract changes (#23065) (d821f2b)
compaction: Merge unique label sets to one global ID during compaction (#24107) (48e7ae3)
compaction: Observability for log compaction (#23122) (aa5e221)
compaction: Track dataobj compaction artifacts via arrow record results (#23364) (47f6607)
compactor: Add new increase_generation_numbers endpoint (#22443) (4649720)
compactor: Improve dataobj compaction planner logging (#23752) (cf17501)
compactor: Reuse logsobj builder metrics (#22138) (bd6316d)
compactor: Take the LogMerge stream layout from the source objects (#25576) (859aea2)
dataobj-compactor: Add an IndexFilter compaction task (#25024) (1aac226)
dataobj-compactor: Add compaction dry-run flag with audit logging (#22308) (0b12196)
dataobj-compactor: Add CompactionMerge physical-plan node (#21844) (12c419b)
dataobj-compactor: Add compactor target skeleton, no-op coordinator stub (#21818) (4cd2cf1)
dataobj-compactor: Add dataobj-compactor-worker target scaffold (#21873) (3a3245b)
dataobj-compactor: Add metrics for duplicates & log-merge throughput (#24952) (fbafe9e)
dataobj-compactor: Bucket log compaction bytes by age (#25127) (0c70fcc)
dataobj-compactor: Calculate compaction runs/jobs (#21845) (3dd8056)
dataobj-compactor: Check index file reachability before log-merge (#25151) (1b30992)
dataobj-compactor: Compactor coordinator/planner main loop (#21973) (5790955)
dataobj-compactor: Index compaction metrics (#22087) (89ea0d4)
dataobj-compactor: IndexMerge executor over postings + stats sections (#22233) (030dd44)
dataobj-compactor: Introduce sized compaction levels (#24987) (4a7284a)
dataobj-compactor: Keep unmerged runs by filtering the source index (#25027) (a2a927d)
dataobj-compactor: Log compaction planning and scheduling (#23125) (6034cdc)
dataobj-compactor: Log merge executor planning (#23201) (03cf02a)
dataobj-compactor: Tighten Planner<>Worker result contract (#24796) (83669cd)
dataobj-compactor: Treat unfilled levels as Converged (#25000) (e1cbc94)
dataobj-inspect: support more section types (#21269) (286bca7)
dataobj/explorer: Decode indexpointers rows in inspect endpoint (#22276) (fe7529a)
dataobj/postings,stats: Add merge builders and row decoders (#22229) (03cd800)
dataobj: Add an indexer that builds one index object per data object (#24638) (c630246)
dataobj: Add bloom and regex pushdown predicates to dataset scans (#22551) (fa9c6f4)
dataobj: Add metadata cache mechanism for data object opens (#24553) (174912b)
dataobj: Add Metastore.SectionsStream() support (#25426) (4f8e001)
dataobj: Add postings Scanner with pushed-down selection (#22582) (71a5792)
dataobj: Add sort_schema config and feature flag (#21460) (30549ac)
dataobj: Add stream-first data-object query integration test (#24986) (e16bfc3)
dataobj: Back off idle compaction workers to spare object storage (#23372) (1c57d2c)
dataobj: Build single-tenant data objects and ToCs (#24791) (41a02c2)
dataobj: Decide data object routing in the query-frontend (#25117) (f006543)
dataobj: Enable lazy downloading of pages in batches when reading dataobj (#24041) (bf703b0)
dataobj: Export required builder replicas from the builder of partition 0 (#25198) (6731504)
dataobj: Filter streams by shard bucket range (#24594) (8522c1a)
dataobj: Flush the builders of a flush concurrently (#25164) (64465da)
dataobj: Implement sort schema (#21557) (a2c4884)
dataobj: Introduce per-tenant shard factor override (#25200) (7383d1a)
dataobj: Keep consuming records while the previous flush runs (#25375) (58b23c2)
dataobj: Match stream IDs in the streams row reader (#24592) (98def97)
dataobj: Persist shard bucket in index objects (#24010) (3b9130a)
dataobj: Plan reads as the metastore streams sections (#25500) (fdb6b7a)
dataobj: Plug the metadata cache into the querier (#25014) (804975b)
dataobj: Project columns in the logs row reader (#24585) (51a4cb1)
dataobj: Prune index rows by shard bucket range when resolving sections (#25138) (3fc344f)
dataobj: Read the stream layout only from the streams section (#25578) (a26d83b)
dataobj: Record index sizes (file + uncompressed logs) in the ToC (#23331) (0172979)
dataobj: Record the stream layout in the streams section (#25575) (4b85657)
dataobj: Reduce postings indexing allocations via observe/aggregate pattern (#21610) (96a0574)
dataobj: Schedule LogMerge via per-tenant IndexMerge/LogMerge flip-flop (#23316) (c70cfc5)
dataobj: Split per-tenant compaction into index and log toggles (#23371) (7a34f30)
dataobj: Write min/max shard buckets to index files (#24225) (8b80648)
default loki-mixin dashboards to TSDB (#18732) (d5fa6f7)
distributor: Add a configurable cap on ratestore based stream shard count (#25023) (0935e4b)
distributor: Add histogram metric for streams per push request (#24943) (fdb9de0)
distributor: Add live mode for limits-service stream sharding (#24788) (8181fd0)
distributor: Add OTLP parser config to defer resource and scope attribute expansion (#24818) (d54d3a3)
distributor: Add produce latency histogram to dataobj-tee (#22068) (047870d)
distributor: Compare shard counts against the ingest-limits service (#24687) (5f9c1fc)
distributor: Generalize backfill day to opaque shard and disable Loki time sharding for backfill (#23248) (d083dcd)
distributor: Skip reject_old_samples validation for backfill streams (#23723) (74c40cf)
Drop streams with special labels in pattern ingesters (#25362) (efa4300)
engine/physicalpb: Add IndexMerge node marshalling (#22231) (b3e9265)
engine/workflow: Add dormant taskTypeCompaction admission lane (#21813) (4e9a034)
engine: Name the unimplemented feature when the v2 engine falls back (#22365) (9967e80)
fluentd: bump version (#21337) (33fdfa1)
handle context cancelation in memcached batching (#21625) (abc30f5)
helm: Update charts for GEL (#21590) (733fb71)
Improve index builder performance by not holding the lock during the whole Calculate (#21632) (08820d7)
index-gateway: Add /sync-indexes endpoint for on-demand index sync (#22637) (cc1f4f4)
index-gateway: Cache expanded TSDB postings (#24453) (5592b35)
index-gateway: Reuse postings cache entries across fingerprint shards (#25038) (605cb65)
indexgateway: Add admission control to bound concurrent requests (#23932) (d8e1eaa)
ingester: Add /flush/tenant endpoint to flush a tenant and ship its index (#22499) (5da6fee)
ingester: Add stream-first sample order to the ingester (#24684) (9f86cc9)
ingester: Flush only chunks by default in /flush/tenant (#25201) (016176b)
ingester: Set chunk IngestedAt at flush for backfilled streams (#22812) (ba89e12)
Introduce max-age option for index-builder (#21294) (4772bfc)
Introduce per-tenant setting to allow rejecting partial pushes for policies (#25074) (de0378b)
Introduce tsdb.shipper.index-reader-mode feature flag (#23663) (828efbc)
iter: Add stream-first sample iterator merge (#24539) (77a72aa)
kafka: Add native histograms for Produce latency (#25069) (88b4d9b)
kafka: Kafka decoders support both formats (#24244) (52c7d20)
kafka: Kafka encoder for InternalPushRequest proto (#24412) (fd9742a)
kafka: Reject partial produces when the buffer is full (#22417) (1be4ce7)
lbac: Promote label-based access control to GA (#25231) (b13a0ab)
limits-service: Persist streamShardStore state (#24752) (0603711)
logcli: Return errors from library and handle fatal in CLI (#18778) (68171cf)
logline: Add correctness as a Loki target (#24799) (e5ca8ec)
logline: Add hint-time-range wire contracts (#24606) (b875553)
logline: Add v4 index version with 9-digit numeric n-grams (#24468) (7bea31c)
logline: Apply hint ranges in queriers (#24714) (2fc573e)
logline: Attach hint ranges instead of envelope fan-out (#24740) (febb425)
logline: Better regex literals selection (#24800) (e3ebecb)
logline: Carry hint ranges through query transport (#24607) (58d7fb6)
logline: Dry-run supported instant metric queries (#25507) (f5362e5)
logline: Dry-run supported range metric queries (#25214) (40286e6)
logline: Fork v3/v4 into in-development v5 (#24820) (4d5c2cf)
logline: Let the compactor write Elias-Fano postings (#25435) (2348cbd)
logline: Read Elias-Fano postings (#24859) (d795bca)
logline: Report Logline query stats on the metrics.go line (#24991) (864308d)
logline: Report Logline stats and outcome in data.stats.logline (#25082) (a351ab5)
logline: Report the hint wait time per query (#25251) (bad4df1)
logline: Route cache-miss hint lookups through queriers (#24678) (d041a69)
logline: Run the compaction scheduler and compactor as Loki targets (#25146) (1c0a52e)
logline: Run the index builder as a Loki target (#24480) (65a51cd)
logline: Split Logline filters into k gap-cut envelopes (#24475) (8853153)
logline: Wire logline filtering into the query frontend (#24727) (3105b2b)
logql: Add approx_count_distinct syntax and extractor (#24112) (e70b294)
logql: Add per-tenant query bytes counter metric (#23382) (3fd2d13)
logql: Add support to evaluate sum(count_over_time) in stream-first order (#24851) (404dfbf)
logql: Evaluate approx_count_distinct with HyperLogLog (#24114) (21d9d6b)
logql: Evaluate CountDistinctSketchExpr as mergeable HLL sketches (#24196) (79c7a7d)
logql: Evaluate sum of sum_over_time in stream-first order (#25438) (d459abd)
logql: Log stream-first and timestamp-first query counts in metrics.go (#25017) (c434fe9)
logql: Log the error on the query stats line (#25004) (46fec29)
logql: Report estimated_query_bytes from index-stats lookups (#21796) (35ca2f6)
logql: Shard and transport approx_count_distinct sketches (#24120) (3969791)
logql: Track stream-first query stats, add integration test (#24984) (d3faa49)
loki-canary: Support bearer token auth (#24533) (0473a09)
lokitool: Rename rules lint to rules format (#21671) (01f2177)
metastore: Add postings metrics (#22946) (35d5a2a)
metastore: Add read-path metrics and locality stats for postings index (#22493) (667368f)
metastore: Add TableOfContentsWriter.ReplaceIndexPointers method (#21932) (10fc249)
metastore: Drive stream selection through the postings Scanner (#22583) (e3b83f0)
metastore: Enable range stats for postings section columns (#23185) (0e298b6)
metastore: Open postings sections concurrently (#23187) (5a871e4)
more accurate counts of max_inflight_bytes (#21611) (4965669)
Move logline hintprovider and logline/v3 to Loki (#24440) (9c24b8d)
Move logline query-frontend and limits to Loki (#24455) (f25906d)
Move some logline packages to Loki (#24435) (d769a31)
On-disk serialization for postings and stats index sections (#21591) (deff86d)
operator: Add CPU and memory utilization ratio telemetry recording rules (#23379) (4cc1c43)
operator: Add LokiStack telemetry recording rules for OpenShift (#22505) (18ad527)
operator: Add passthrough-gateway component (#20382) (bf06e45)
operator: Add support for full TLS compliance for OCP 5.0 (#24216) (8ce415a)
operator: Allow custom certs to be used by the passthrough gateway tenancy (#23896) (abf69d1)
operator: Allow removal of expired schemas based on retention period (#24456) (16446f8)
operator: Enable flush_on_shutdown and increase ingester terminationGracePeriodSeconds (#24325) (90c3797)
operator: Enable multi-variant queries (#21009) (709e318)
operator: Introduce passthrough tenancy (#20573) (ca8aac8)
operator: Make schemas field required in storage spec (#24716) (071148c)
operator: migrate to thanos objstore backend (#20475) (ffcac2c)
operator: Produce metrics about managed LokiStacks (#21838) (2f0e0ba)
operator: Remove obsolete warning about old schema versions (#25155) (1d6f9e2)
operator: Stop reconciliation of deprecated BoltDB schemas (#24990) (4c138a9)
operator: Support private VPC S3 endpoints in endpoint validation (#22395) (394caef)
operator: Update Loki operand to 3.7.7 (#24448) (04417f4)
operator: Update Loki operand to 3.7.8 (#24743) (f1f1b23)
operator: Update Loki operand to v3.7.2 (#22075) (01499dc)
operator: Update Loki operand to v3.7.3 (#22645) (f64e9ac)
operator: Update ServiceMonitors to use serviceDiscoveryRole: EndpointSlice (#21731) (d3a12c7)
operator: Watch object storage Services for NetworkPolicy updates and surface ports in status (#22436) (12822d5)
otlp: add event_name to OTLP log structured metadata (#21229) (c9a1785)
otlp: Adds a reporter to view attributes expanded to structured metadata (#23637) (88a08ba)
pattern-ingester: Add a gRPC method that accepts InternalPushRequest (#25006) (f0dfaa0)
pattern: Make stream ownership pluggable for Kafka ingestion (#25408) (a3b624e)
pattern: Support both gRPC and Kafka ingestion (#25432) (ebd3000)
postings: Add postings data locality to xcap (#23070) (5de9bad)
querier: Add object-store and section resolution metrics to data-object queries (#25034) (e1f0dc3)
querier: Read metric queries from data objects (#24699) (d2d7405)
querier: Read stream-first metric queries from data objects (#24897) (b0fcdb8)
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)
querylimits: Allow TSDB sharding strategy overrides (#22332) (a0f24ce)
querytee: Add selection strategies for the secondary backend (#25615) (78990d2)
querytee: Add the data object flags and read only the limits from the Loki config (#25633) (8cd4007)
querytee: Compare the stats of the secondary backend with the primary's (#25623) (ed69fdc)
querytee: route v2-unsupported request types directly to v1 in SplittingHandler (#21450) (4515b4b)
Remove Promtail support (#21245) (572df01)
Remove support for experimental LogQL variants() queries (#23823) (132e5f9)
Remove task_pruning_cache_fetch_batch_size in favor of existing memcached batching (#21593) (24ca0e4)
Rendezvous shuffle sharding algorithm for data objects with opt in configuration (#22167) (60db1ba)
Resolve cached tasks in parent task (#21558) (904c963)
retention: Use chunk IngestedAt for retention decisions (#22819) (e16efe7)
return caching stats in new engine (#21369) (c32b57f)
ruler: Always wipe the remote-write WAL on startup (#22509) (636c007)
s3: Update thanos-io/objstore fork to add connection metrics (#25170) (89564d0)
storage: Add custom TLS CA certificate support for Azure Blob Storage connections (#23062) (3a68a80)
storage: Add stream-first sample order to the chunk store (#24562) (8eb103b)
Support more kafka producer options (#24402) (bd2cc6f)
Support per-policy stream sharding overrides (#22451) (8ee465e)
tools: Adds a CLI for measuring postings and logs locality (#23103) (61f1bb4)
tsdb: Add FormatV4 reader and writer foundation (#22370) (3b7142e)
Upgrade Go module to github.com/grafana/loki/v4 (#25972) (7af5f26)
Use AppendOrdered strategy to avoid sorting and merging stripes (#21395) (bd7530f)
use query logger on metastore workflow (#21511) (b68de56)
validation: Add inherit_limits flag to per-policy override limits (#23751) (bcc85b0)
WIP: Task level caching (#21160) (bd51fca)
Write all Kafka records at once (#21542) (fe7f43b)

Performance Improvements

Allocate capacity for fewer pattern samples up front (#23600) (0756067)
avoid unnecessary shuffle sharding (#21344) (34e5cc9)
blooms: return full slice to pool after use (#20981) (9d9c7af)
chunkenc: Remove the per-sample allocation from the dedup hash (#23821) (b3676fa)
compactor: Key TSDB builder streams by labels hash (#25593) (ba46804)
dataobj: Compile predicates once per read instead of once per row (#24982) (ffd778d)
dataobj: Flush the largest builder first (#25376) (0fbc71b)
dataobj: Memoize repeated stream ID lookups in the logs row reader (#25016) (9732690)
dataobj: Prefetch 64 KiB when Sections opens an index object (#25244) (d819053)
dataobj: Speed up index compaction (O(1) stats size, trim postings bitmaps) (#23274) (f3388e0)
engine: Short-circuit DataObjScan when logs predicate is unsatisfiable (#22162) (a7adf30)
Hold on to less memory by trimming results down to request limit (#24198) (8c1864a)
idx-gateway: Use the label values fast path when no matchers are given (#24831) (f3c840c)
index-gateway: Deduplicate concurrent postings cache lookups (#25039) (76a0ce2)
indexgateway: Avoid retaining chunk refs during shard sizing (#24723) (6e9c738)
indexgateway: Only calculate chunk groups if we're going to return them (#24113) (7325deb)
indexshipper: Open downloaded index files before taking the index set write lock (#24832) (df68cbc)
Lazy instantiation of drains for pattern ingesters (#23944) (3d6cc54)
logline: Compress postings blocks at zstd level 3 (#24824) (b6ffedf)
logline: Merge index shards concurrently (#24713) (a54ada3)
logline: Run pass-through intervals without waiting for the hint lookup (#25259) (d3b010f)
logql/log: Hash labels before building them, not after (#24933) (f32bf19)
logql: Add constant-label fast path for sample extraction (#24368) (eb837b0)
logql: Cap series accumulation at the max_query_series limit (#23123) (871ed63)
Optimise rendezvous shuffle sharding algorithm (#22269) (69822a3)
querier: Avoid expensive shuffle sharding when shardSize=0 (#22912) (f8aad8a)
querier: Evaluate the pushed line filter on the decoded column (#25233) (4c2cfd3)
querier: Narrow the dataobj read projection for a query that can error (#24853) (db94fd0)
querier: Push line filters into the data-object read (#25147) (f0a69b5)
querier: Run each pushed line filter once (#25189) (59878bf)
Read the streaming index window with pread (#24437) (417faee)
Replace drain prefix tree map with a slice (#23949) (d13b0b2)
short-circuit cache when over max cacheable size (#21277) (5f06abe)
support shuffle shard by tenant to increase cache hits (#21357) (787276e)
tsdb: Add defer closure missed from #20970 (#20978) (e9d724c)
tsdb: Merge postings lists with a loser tree (#25165) (e4a3b30)
tsdb: Only pool streaming postings list buffers of 256 bytes or more (#25508) (cf6ef69)
tsdb: Read a streaming postings lookup through one decbuf (#25368) (11568ef)