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
846c8d6335