I-1: a node whose in-memory trail is one short of the stored trail (it missed
a command the peer applied, whose entry then replicated in) silently dropped
its own next entry — in failover, the survivor's newest ack — because the
positional "past MAX(seq)" rule treated it as already stored.
SaveAsync now reconciles the last 16 in-memory entries against the stored
rows from that position on, by content (Kind/User/Text, timestamps within a
5-minute skew window; matched rows are consumed so repeats count). The peer's
copy of the same command is recognised and not re-appended; an unmatched
entry is inserted at its own ordinal when free, otherwise appended at
MAX(seq)+1 with a Warning — kept, never silent. Bounded read, constant write.
m1: MigrateInlineComments copies only — it no longer UPDATEs the condition
row (a fresh-HLC re-stamp could beat a newer peer ack under LWW); the next
save clears comments_json. m2: it returns unparseable alarm ids and OnReady
logs a Warning per id (+ an Information tally). m3/m4: documented in the
store remarks (Remove vs lagging peer; in-memory index == durable ordinal).
Tests: store-level failover sequence (missed command -> survivor's ack and
next entry persisted once, re-save writes 0 rows, one Warning) with the
dual-write positive control (peer copy present -> 0 rows, no Warning) and a
repeated-identical-comment case; a loopback pair failover test (link down,
survivor acks, rejoin -> both entries on both peers, held); migration
no-row-rewrite, partial fill and unparseable reporting; OnReady Warning.
Both failover tests fail against the round-0 store.
Refs #748
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
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
Joseph Doherty