commit_txn issued an unconditional fsync per COMMIT, so N concurrent
writers serialized behind N disk syncs (p99 hit the 3s socket timeout
under 8 writers). Add Wal::sync_upto: committers queue on an fsync_gate,
the first one flushes the whole accumulated buffer, and waiters that find
committed_seq past their target return with zero I/O. N commits now cost
~1 fsync with the same durability guarantee.
Also fix a durability over-report: flush_pending stamped committed_seq
from the LIVE seq counter, so sequences taken by appenders that had not
yet buffered their bytes were reported durable. Track max_seq alongside
the pending buffer and advance committed_seq only to what was written.
Wire --wal-fsync-ms / --checkpoint-ms in cube-server (previously
hardcoded to defaults, so the documented knob did nothing).
Both regressions are mutation-verified: each test fails when its bug is
reintroduced.
- TenantRegistry gains a true single-store 'shared' mode so the legacy
--store PATH invocation (and stress.sh / old cubec) keeps serving one
global store, while still parsing HELLO frames.
- cube-server now holds an Arc<TenantRegistry>, resolves each connection to
its tenant's TenantSession, and stamps the client identity from
HELLO <tenant> <owner_local> [<owner_remote>].
- Add --tenant-dir DIR for real per-tenant disk isolation (opt-in).
- Add TenantIdentity + TenantRegistry::parse_hello and a shared-session
integration test.
TenantConfig::Disk opens each tenant's ConcurrentStore under its own
sanitized subdir of store_dir (path separators -> '_', no traversal escape),
reusing the durable WAL+checkpoint machinery (incl. 49698af delta-path fix).
Registry takes a config; get_or_provision returns io::Result so a disk
open failure surfaces instead of silently falling back to memory.
Tests: tenant_store_is_isolated_on_disk (separate dirs + survives reopen,
B still isolated) + tenant_id_cannot_traverse_store_dir. ./check green.
Add TenantId (from-str, normalized, non-empty) and TenantRegistry that
provisions one isolated TenantSession per tenant behind an RwLock<HashMap>.
In-memory store only for now; disk-backed per-tenant stores + daemon wiring
land in Tasks 2-3. 4 unit tests pass, ./check green.
CUBELinux-2