v0.3.0

Performance

Metrics engine

• Resident compact block index (columnar fields + dictionary labels), removing repeated directory
  decodes and label-string allocations.
• Series-partitioned parallelism for range-step queries across workers.
• Streamed exact path for dense-block queries; bulk read of the chunk section instead of one ReadAt per
  series.
• Binary block directory, byte-budgeted directory cache, range-step scratch reuse.
• Stats is now O(blocks) via manifest sample counts; catalog REGISTER records batched behind one commit
  wait.

Index / FTS

• Replaced roaring with sorted-slice bitmap sets (ULID keys shattered roaring containers).
• Posting-list FTS format replaces the radix snapshot (38MB to 5MB per segment).
• pread-backed token lookups, df==1 tokens in a flat hash section, arena-backed seal build state.

Storage / Query

• 512KiB blocks with footer v3 per-block time bounds to prune reverse-window scans.
• pread-based segment scans; shared readers no longer serialize.
• Bitmap prefilter for multi-value service/host/level filters; result-cache invalidation scoped to the
  ingest batch time range.

Durability and correctness

• Binary WAL with series/sample records and a flush gate against acked-sample loss.
• Fail-stop WAL/segment/catalog writers after fsync or partial-write errors; WAL CRC covers length and
  sequence.
• Recovery: truncate the uncheckpointed active segment to avoid replay duplication; heal orphan segments
  from the create/saveMeta crash window.
• Histogram sketches unified into the main store; crash-safe histogram compaction with marker recovery.

Features

• rate_range endpoint exposing per-step range rates for metrics.
• MemoryLimit option setting the Go soft memory limit at open.
• db.Flush durability barrier and data-dir locking.

Benchmarks

• New obsbench harness: datagen, ingest loadgen, memory sampler, preflight.
• Log scenarios Q1-Q4 and metrics scenarios QM1-QM4 (OTLP) with result-count equality gates.
• kill -9 durability-loss orchestration and queryable-count verification.

Other

• Documentation across all packages (model, storage, index, query, ingest, metricsengine, api/http,
  runtime).
• CI pipeline with static checks gating build and test.
• README updated with campaign medians; lint cleanup and go mod tidy.

v0.2.0

v0.2.0

Features

• Public embed API: amber.Open, Options, Cardinality, S3 config — stable surface for embedding amber into another binary.
• S3 segment tiering: SegmentStore interface with LocalStore and S3Store implementations, automatic upload on seal.
• Posting list index for trace_id — replaces bitmap for high-cardinality fields.
• Ribbon filter for segment-level pruning.
• Cardinality guard: caps attrs per entry, attr value length, and unique keys per service.
• Circuit breaker rejects writes after consecutive batch failures.
• Prometheus /metrics endpoint with ingest and WAL counters (hand-rolled exporter, no client_golang dependency).
• /readyz gate and per-request size limits on the HTTP API.
• Timing-safe API key comparison, gated pprof.

Performance

• Zero-copy block scan: ~100k allocations -> ~40 per segment scan.
• processBatch allocations halved via metric handles and zstd encoder reuse.

Bug fixes

• Segment header is now fsynced before WAL replay (fixes zero-byte segment after crash).
• WAL replay caps per-record size and surfaces corruption events.
• Writer state and activeSize correctly restored after restart.
• Atomic index writes; WAL checkpoint durability.
• Rotation no longer reopens readers; retention sort fixed; seal retry on failure.

Tests

• Real SIGKILL chaos test for WAL recovery (subprocess + atomic marker).
• Contract test for the public embed API (amber_example_test.go).
• White-box benchmarks for query, ingest, storage, and indexer paths.
• 10M-record self-tracking benchmark (loadbench) with write/memory/read metrics.
• Metrics exporter coverage: counters, escaping, exposition format.

Tooling

• loadbench, lokibench, vlbench, httpbench — apples-to-apples benchmarks against Loki and VictoriaLogs over HTTP.
• lefthook pre-commit and pre-push hooks (gofmt, govet, golangci-lint, tests).

v0.1.20

• fix stale segment metadata after retention cleanup
• return explicit overload failures when ingest queue is full
• improve OTLP/HTTP ingest rejection handling
• add regression tests for traces, ingest, and retention

v0.1.19

• alpha version amber