Every Part 9 transition used to re-serialize the alarm's whole comment trail
into alarm_condition_state.comments_json and replicate it to the pair peer:
O(n) per transition, O(n^2) over an alarm's life (measured: one ack at 10k
comments shipped 1,080,553 oplog bytes; now ~1.6 KB, the same as at 10).
- New replicated table alarm_condition_comment, PK (scripted_alarm_id, seq),
seq = the entry's ordinal in the trail. Ordinal (not content) keying makes
the two pair nodes' copies of one logical entry (each stamped by its own
clock, since both nodes apply every command) collapse to one row under LWW.
- LocalDbAlarmConditionStateStore.SaveAsync appends only entries past the
stored MAX(seq) (INSERT OR IGNORE, append-only) and upserts a fixed-size
condition row with comments_json = "[]", in one transaction. Remove drops
the trail with the row. Load merges the table with any inline trail.
- comments_json column kept (always "[]") so the condition table's shape and
replication digest are unchanged and old-shape rows still load exactly.
- AlarmConditionStateSchema.MigrateInlineComments: idempotent per-row move of
inline trails, run by LocalDbSetup.OnReady after RegisterReplicated so the
moved entries replicate. Comment table joins ReplicatedTables (now five).
Tests: constant transition payload at 10 vs 10k comments (+ instrument
positive control), old-shape back-compat load, migration idempotency /
partial re-run / lazy move, OnReady boot migration captured in the oplog,
and two loopback pair tests (A->B and B->A trail convergence; the shared
entry converges to one copy, with a distinct-alarm positive control).
Refs #748
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
LocalDbSetup.OnReady registered all four replicated tables unconditionally on
every driver node, replicating or not. That was not merely wasteful (an
unreplicated node paid two INSERTs plus a json_object of the whole row inside
every write transaction, for an oplog nothing ever drained) — it made
baselineExistingRows unusable, so enabling replication on a long-running
default-OFF node converged on SUBSEQUENT WRITES ONLY and the rows already in the
file stayed invisible to the peer, silently and forever.
Registration now follows one predicate, LocalDbSetup.ReplicationIsConfigured:
LocalDb:Replication:PeerAddress OR :ApiKey non-blank. The OR is load-bearing —
only the dialling half of a pair sets PeerAddress, so keying on it alone would
strip capture from every passive node and the pair would converge in one
direction only. SyncListenPort deliberately does not join it: the passive
endpoint is fail-closed on the key, so a port with no ApiKey syncs with nobody.
configured => RegisterReplicated(table, baselineExistingRows: true), per
table, in the unchanged load-bearing DDL->register order
unconfigured => DeregisterReplicated(table), an idempotent boot self-heal that
drops the capture triggers an earlier build left behind and
prunes that table's oplog/row-version rows. One Information
line, only when it actually cleaned something.
PAIR SYMMETRY: the sync handshake compares registered-table digests fail-closed,
so flipping either key is a both-nodes-together change — set it on both and
restart both. Documented in CLAUDE.md, docs/Configuration.md and the replication
runbook (which claimed "this repo never calls DeregisterReplicated").
Verified against the pinned LocalDb 0.2.1: RegisterReplicated(string, bool) and
DeregisterReplicated(string) -> bool both exist; baselining seeds
__localdb_row_version at HLC 0 and the deregister return value distinguishes
"cleaned" from "nothing to clean". No pin bump needed.
Tests: LocalDbSetupTests gains pins for both branches (configured via
PeerAddress alone and via ApiKey alone; unconfigured => no tables, zero
triggers; late-enable => an HLC-0 baseline ledger entry; the log line fires once
and only when something was cleaned) — four went red against the old
unconditional code, and all four go red again under a constant-true predicate.
LocalDbWiringTests splits its exact-set pin into a replicating graph and a
default-OFF one. LocalDbPairHarness and AlarmSfLegacyMigratorTests built their
database from LocalDb:Path alone while configuring the replication engine from a
second config — production reads one configuration, so the two are now aligned.
Host.IntegrationTests: 224 passed, 0 failed, 5 skipped.
Nullable ConfigDb factory; UpsertNodeDeploymentState no-ops when absent
(central persists acks from the ApplyAck); scripted-alarm condition state
served from the LocalDb store instead of the ConfigDb-backed Ef store.
Combines Phase-4 Tasks 4 + 6. Removes the interim dbFactory! cast.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Two driver nodes replicating the alarm buffer over the real loopback h2c
transport, through the real fail-closed interceptor. This is the test the
phase exists to pass: schema, registration, sink rewire and drain gate can
all be individually green while a pair still fails to share the undelivered
alarm history that is the whole point of moving the queue.
Rows are written through the production sink rather than hand-rolled
INSERTs, so the id derivation, column set and delete-on-ack semantics under
test are the ones production uses. The scenarios cover a buffered burst
converging with the oplog draining to zero, delivered rows being removed from
BOTH nodes as tombstones (the no-redeliver-after-failover property), writes
during a transport outage surviving the rejoin, and the same event accepted
on both nodes collapsing to one row.
The positive control found a weak assertion. With
RegisterReplicated("alarm_sf_events") commented out, three of the four went
red immediately -- but the same-event-on-both-nodes scenario still PASSED,
because with replication off each node trivially holds its own single copy
and "one row on each" is satisfied by two databases that never spoke. It now
also enqueues a distinct event on B and requires both nodes to hold two rows,
which cannot be satisfied without convergence; it goes red under the control
like the others. Control restored, all four green.
Also updates the second exact-set replicated-tables pin, in LocalDbWiringTests.
The plan predicted these pins would go red here, and that is them working:
one of them is asserted through the full driver DI graph rather than the
OnReady callback, so it catches a registration that exists in the callback
but never reaches a running host.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Builds a container from the same AddOtOpcUa* methods Program.cs's driver branch
calls (AddOtOpcUaLocalDb / AddGrpc / AddOtOpcUaHealth / AddOtOpcUaObservability) and
resolves through it - DI extensions have shipped inert three times in this family.
Does not boot the real host: WebApplicationFactory<Program> would start hosted
services (Akka, OPC UA server, ValidateOnStart) needing SQL + a mesh, per D-5. The
seam under test is DI resolution, so the container is built and resolved without
starting.
Five pins: ILocalDb singleton + exact replicated-table set; IDeploymentArtifactCache
-> concrete; default-OFF ISyncStatus; localdb-replication health check registered and
constructible; admin-only graph has NO ILocalDb and does not demand LocalDb:Path.
Joseph Doherty