YantrikDB

Interim point release between v0.6.6 (decoupled write path Phases 1-5) and v0.7.0 (still gated on Phase 4.3 SQL-off-foreground + Phase 7 soak ~80h combined). Lets yantrikdb-server consume the cluster RYW design refinements without waiting another 3 weeks.

Highlights

• DEFAULT_DELTA_MAX 1024 → 256 — write tput +70%, read p50 -53% (better than even v0.6.5 baseline). Smaller delta keeps per-search linear scans cheap and triggers compaction often enough that cold absorbs the working set.
• Cluster RYW design lock — all 4 cluster primitives accept Option<u64> seq + required namespace, bump visible_seq for snapshot-lag determinism on followers. Engine seq IS the openraft commit-log index.
• Lock-free RYW hot path — visible_seq refactored to DashMap<String, AtomicU64> so recall_with_seq reads no longer contend on a global mutex.
• Age-based compaction trigger — closes the idle-delta gap where a low-write namespace would never compact. Default 60s, tunable via YANTRIKDB_MAX_DIRTY_AGE_SECS.
• CONCURRENCY.md — 8 load-bearing invariants documented at repo root, each naming the failure mode if violated.

What's in this release vs v0.6.6 (6 commits)

```
84318c0 perf(delta_index): DEFAULT_DELTA_MAX 1024 → 256
8a92ae1 refactor(error): RyWaitTimeout fields → requested_seq /
observed_seq /
waited_ms
5102b6f feat(cluster): seq + namespace + visible_seq bump on
all 4 cluster primitives
dd2cfd3 perf(ryw): visible_seq → DashMap<String, AtomicU64>
a4df7bf feat(compactor): age-based compaction trigger for idle deltas
53bca81 docs(concurrency): add CONCURRENCY.md with 8 invariants
```

Breaking changes (pre-1.0)

These were pre-coordinated with yantrikdb-server before landing:

• `tombstone_with_rid` now takes `namespace: &str` before `reason`
• `delete_entity_edge_with_id` now takes `namespace: &str` after edge_id
• All four cluster primitives gained trailing `seq: Option`
• `Error::RyWaitTimeout` fields renamed: `min_seq` → `requested_seq`, `visible` → `observed_seq`, `timeout_ms` → `waited_ms`

Tests

1399 lib tests pass (was 1380 at v0.6.6). 5 new age-trigger tests + 4 new RYW seq tests covering snapshot-lag determinism on followers.

Still pending for v0.7.0

• Phase 4.3 — SQL writes off foreground (entity-link inserts) ~40h
• Phase 7 — Long-duration soak validation ~40h

Architecture

The v0.6.7 architecture is now diagrammed in README.md — two Mermaid diagrams covering the decoupled write path and cluster mode RYW. CONCURRENCY.md is the canonical reference for the engine concurrency invariants.