1 PersistNodeAck wrote a Failed ack's FailureReason unbounded; the column is
nvarchar(2048), so on SQL Server the write failed forever, the ack retried
forever, the deadline deferred forever and every later deploy was refused.
- One shared bound, Configuration.FailureReasons.Truncate (MaxLength 2048),
used by the coordinator and DriverHostActor.UpsertNodeDeploymentState
(exception messages and degraded reasons).
- A non-transient DbUpdateException (not concurrency, no transient
DbException / timeout / socket / IO underneath) is POISON: the ack is
counted from memory with an Error, never retried.
- Deadline deferral on unpersisted acks is capped at 10 x the retry ceiling;
past it the outcome is decided from the acks held in memory.
2 A node restarting in the outcome window boots the cached revision (cache is
written before the outcome) and never acks. Cache-booted revisions
(BootstrapFromCache / TryBootFromCache) are now marked unconfirmed, so a
re-dispatch re-applies and acks the real outcome instead of a clean
short-circuit. docs/Redundancy.md corrected (replay only on the ConfigDb boot
path).
3 A lost dispatch re-driven near its deadline now gets a FULL deadline (a node
needs its whole outcome timeout + margin = ApplyDeadline, so any shorter
remainder timed out nodes that applied). No dispatched-at column: a second
restart recomputes from CreatedAtUtc and closes it instead (documented).
4 docs/Redundancy.md upgrade note: do not deploy while the central pair is mid
rolling-upgrade across this change.
Tests (all fail on the previous code): oversized Failed reason truncated (on a
SaveChanges interceptor that enforces the column like SQL Server); rejected ack
write counted from memory; bounded deadline deferral; full deadline on a
near-deadline re-drive; cache-booted revision re-applies on re-dispatch;
oversized degraded reason truncated on the node's own row.
Claude-Session: https://claude.ai/code/session_01GT67AD99zQQqpLCVm3p7xk
Joseph Doherty
780c87eba3