End the "replicated XOR sharded" split: S shard groups, each a
replication group at RF with its own elected leader, leaders balanced
across nodes; any gateway hash-routes.
- One unified write surface: /items,/embeddings,/signals hash-route to
the owning shard group's leader (ShardRouter FNV-1a) AND replicate at
RF. x-tidal-ack/x-tidal-seq, quorum await, NotLeader/QuorumTimeout are
per-group; NotLeader names the group.
- Rebalance verbs (L3): POST /cluster/shards/{id}/transfer (fenced
leadership move) + /cluster/shards/{id}/replicas (add/remove replica).
A ?shard= selector threads through every per-shard admin verb and is
propagated on intra-group forwards (ShardReplica::admin_path). S=1 is
byte-for-byte (no selector, no shard in NotLeader body).
- Tier-3 exit gate (cluster_sharding.rs): 3 nodes × 3 shards × RF=3 over
real OS processes — SIGKILL a node under ack=quorum load → only its
shard-leaderships re-elect, reads never stop, zero acked loss across
random kill points; plus a rebalance-verb test. Harness:
MultiProcCluster::start_sharded.
- tidal-stress drives the single path (WritePath::Leader|Sharded gone),
spreading writes round-robin across gateways or pinning --leader-url.
- Throughput: local 3×3 sustains 3,000 quorum signal-writes/s @ 0% err,
~30% CPU, lag ~0 (generator-bound). ≥5,000/s + ≥2.5× scaling is Ref-A.
Known follow-up (tracked): per-group-aware node readiness and cross-node
read fan-out under PARTIAL placement.
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| .. | ||
| guides | ||
| ops | ||
| planning | ||
| profiling | ||
| research | ||
| reviews | ||
| runbooks | ||
| specs | ||
| content-strategy.md | ||
| personal-briefing-beachhead.md | ||
| README.md | ||
| roadmap-to-cluster.md | ||
tidalDB Engineering Docs
The engineering documentation home. Top-level product docs (VISION, USE_CASES, SEQUENCE, ARCHITECTURE, API, QUICKSTART, CODING_GUIDELINES, thoughts) live at the repository root; everything below is the deeper engineering record.
This and the repo root are the two canonical doc homes. There is intentionally no per-crate doc mirror (no
tidal/docs/). Edit the canonical file, never a copy.
Component specs — specs/
The authoritative component specifications (status: Implemented, M0–M8).
| # | Spec | # | Spec |
|---|---|---|---|
| 00 | Architecture overview | 08 | Query engine |
| 01 | Storage engine | 09 | Ranking & scoring |
| 02 | Entity model | 10 | Feedback loop |
| 03 | Signal system | 11 | Schema |
| 04 | Relationships | 12 | Cold start |
| 05 | Cohorts | 13 | Concurrency |
| 06 | Text retrieval | 14 | Scale architecture |
| 07 | Vector retrieval |
Planning — planning/
- ROADMAP.md — milestones M0–M11, phase status, known gaps
- roadmap-to-cluster.md — adopted M11 plan: gap analysis + phase specs taking the multi-process cluster from experimental to enterprise-grade (m11p1–p5 ✅; p6–p9 planned), grounded in the 2026-06-10 live stress-test baselines
- PRODUCT_ROADMAP.md · architecture-review.md · roadmap-cohort-analysis.md · site-cohort-analysis.md
- Per-milestone phase/task archive:
planning/milestone-0,1,2,3,5,7,8,9,10,11,p/
Code reviews — reviews/
- M0–M10 code review — 2026-06-07 — seven-dimension re-review, 88 verified findings
- M0–M10 code review — 2026-06-08 — seven-dimension review, 142 findings (latest pass)
- M0–M10 seven-dimension review — additional pass (2 BLOCKERs: signal-checkpoint trim, 30-day window)
Guides — guides/
Task-oriented, build-an-app docs (complements the root QUICKSTART.md and API.md):
- Build a feed app — end-to-end TikTok/Reels-style "For You" feed, embedded and over HTTP
- Embedding integration — wiring a real embedding model (OpenAI / Cohere / local) into the write + query paths
- Server deployment — running the
tidal-serverHTTP service: config, auth, the served OpenAPI spec, Docker - Ranking-profile reference: ai-lookup/services/ranking-profiles.md — all 25 built-in profiles
Operations — ops/ and runbooks/
- Monitoring · Prometheus alerts · Grafana dashboard · Capacity planning · Recovery
- Runbooks: Kubernetes · Cluster (experimental)
Research — research/
ANN (1, 2) · Tantivy (1, 2) · Signal ledger (1, 2) · WAL · Type system · Tooling & diagnostics · Enterprise-readiness risks
Profiling — profiling/
Hotspot analysis · Scale baselines · Signal memory · Signal rollup eval · Social scale · Tantivy merge tuning · USearch tuning