F1: the driver's outage BadNoCommunication carried the last Good sample's
source timestamp. The recorder historizes SourceTimestampUtc ??
ServerTimestampUtc, so the Bad landed on the Good row's (TagId,
SourceTimeUtc) key and the insert-if-absent historian dropped it - no
outage marker until the host's watchdog marker ~95 s in, none at all for
a short blip. Now stamped with the detection time (source + server), as
the host's comms-loss fan does.
F2: after a same-session recovery the SDK delivered a missed notification
seconds late with an older source time and the node regressed. A
notification older than the newest Good upstream source time for its ref
(notification or recovery read) is dropped and counted
(stale_notification_dropped); equal timestamps pass; the outage Bad never
moves the comparison; a re-initialise resets it.
M1: a subscription that dies while the session lives (outage longer than
the subscription lifetime but shorter than the session timeout) used to
end Healthy with fresh keep-alive stamps and frozen values. PublishError
BadNoSubscription / BadSubscriptionIdInvalid naming a tracked
subscription, or a tracked subscription whose SDK PublishingStopped
persists one more keep-alive window + 5 s across good keep-alives, now
declares it lost: Degraded, outage published once, and nothing advances
LastSuccessfulRead until the session is released, so the #527 watchdog
re-initialises and re-subscribes. Both detectors wire-tested.
M2: in-place recovery is bound to the session whose keep-alive recovered;
one overtaken by a re-initialise no longer re-arms the new session's
outage latch or degrades its health (ReadCoreAsync expectedSession).
L1 CAS health updates; L2 re-check before each recovery publish; L3 skip
CloseSession on a lost session; L4 SDK log forwarding rate-limited
(20/min); L5 per-driver SDK LoggerFactory disposed with the driver.
Wire test asserts the read stamp stays frozen while the server is down.
A bad keep-alive now degrades health (LastSuccessfulRead preserved) and,
once per outage, publishes BadNoCommunication (value retained) for every
subscribed ref plus a quality-only annotation on subscribed alarm
conditions. Good keep-alives and data/event notifications advance
LastSuccessfulRead, so an idle-but-alive subscription never looks dead
to the #527 watchdog. A keep-alive that recovers on the same session
re-reads the Bad refs and republishes them Good; a session that does not
come back is recovered by the watchdog's ShutdownAsync + InitializeAsync
+ re-subscribe.
Deletes the SessionReconnectHandler wiring (it retried forever in SDK
1.5.378, cloned subscriptions the driver never re-tracked and kept health
Healthy), OnReconnectComplete, TryRearmReconnect and the reconnect_*
counters (new keepalive_recovered). Teardown of a lost session skips
wire deletes and bounds CloseSession. SDK warnings reach the driver log.
Wire test reworked: restart => Bad, then watchdog-style reinit => Good.
A SIGKILLed Primary stays an unreachable-but-not-downed member until
auto-down, and the redundancy singleton usually dies with it, so the
standby's cached snapshot kept naming it Primary and nobody captured for
~30 s. DriverHostActor now holds its own ReachabilityEvent (+MemberUp)
subscription, caches the last snapshot, and excludes unreachable peers
from the historization peer-is-Primary predicate only, republishing just
the capture verdict on a reachability change. Alarm drain and the Primary
data-plane verdict are unchanged. Gated by
ContinuousHistorization:CaptureWhilePrimaryUnreachable (default true).
Tests: message-driven cases with real ReachabilityEvents (incl. a
falsification control on the drain/data-plane verdicts) plus a real
two-node cluster crash test with downing disabled.
A capped events read now pages: the source's truncation flag triggers a
session-bound cursor (time inclusive + tie skip), oversized tie clusters
are paged within via a bounded half-open over-fetch, and release/unknown/
cross-kind points behave as for Raw.
- I-1: QuestDbConnection caps Npgsql Maximum Pool Size at 24 (DefaultMaxPoolSize)
when the connection string does not set it; an explicit value is kept. The
effective value is logged once at Information.
- M-1: QuestDbTagCatalog.EnsureAsync waits for the tag table's sequenced commits
and re-checks before inserting, so it no longer overwrites a provisioner row
(unit/description) that is committed but not yet applied. Integration test
reproduces the clobber against real QuestDB (falsified).
- M-3: the pre-1970 drop Warning is rate-limited per tag (once per 10 min);
DroppedPre1970 still counts every sample.
- M-5: QuestDbHistorianProvider is IAsyncDisposable/IDisposable and disposes the
shared Npgsql pool; Program.cs registers the provider through a factory and
every seam resolves it from the container, so DI disposes it at shutdown.
- M-8, M-9: docs fixes (HistoryUpdate transaction wording; folded duplicate
HistoryUpdate paragraph). Pool-size docs updated for the new default cap.
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
AtTime conformance stamps are the requested time (M3; identical on SQL Server). The
QuestDB test fixture prunes idle pooled connections after 1 s: undisposed per-test data
sources exhausted QuestDB's 64-connection PG-wire limit in a full run.
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
IHistorianDataSource.TimestampResolutionTicks (default 1; QuestDB 10). A drained tie
cluster now steps off T by the resolution, so a forward one-value-per-page read on a
microsecond backend no longer re-reads the same sample forever (C1). QuestDB AtTime
results carry the client's original request time (M3); regression for the NEXT seek
skipping a tombstone (M1). Conformance backend wires the real writer and updater.
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
QuestDbHistorianDataSource serves Raw (LIMIT $n, no continuation, R8), AtTime
(chunked LIMIT 1 neighbour seeks, <=50 times per statement), Events and
Processed (one statement per node, bucket = (cast(ts AS LONG)*10 - start)/interval,
shared BucketPlan/AggregateEvaluator/AtTimeEvaluator). Every sample read filters
NOT deleted; every row goes through StoredSample.FromStored; RC2 long.MinValue
read repair. QuestDbConformanceBackend (seed/read-back) for the conformance suite;
writer/updater factories are T7 placeholders.
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
Two Sql.Common tests close review finding I-1: an Uncertain NEXT neighbour makes an AtTime
interpolation Uncertain, and an Uncertain (non-Bad) sample in a bucket makes the aggregate
Uncertain. Each falsified with the reviewer's surviving mutation.
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
51 new test cases (34 methods) in Sql.Common.Tests covering AtTimeEvaluator, AggregateEvaluator
(hand-built tag-A bucket rows, ProcessedRead literals), BucketPlan, LiveWritePreparer and
HistoryUpdatePlanner (incl. resolutionTicks=10 truncate-before-dedup and the superseded-duplicate
outcome), plus EventContinuation, HistorianHealthCounters, ClampSeverity and StoredSample.FromStored.
Each was falsified by reverting the rule it pins (37 mutations, all red, all restored).
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
Moves the database-independent logic of the SQL Server historian backend into a new
shared library for the upcoming QuestDB backend (#666): status codes and bits, value/column
mapping, StoredSample + quality clamp, the AtTime and aggregate evaluators, BucketPlan,
LiveWritePreparer and HistoryUpdatePlanner (both with a resolutionTicks parameter, default 1),
tag-name rules, the bootstrap failure cache, health counters, alarm event ids, the event
continuation and severity clamp. The SQL Server backend now calls it; its T-SQL, TVP
builders, connection, bootstrapper and catalog stay.
Tests: StatusCodeOracleTests, ValueWriterPrepareTests, the column half of SampleRowMapperTests
and ProcessedReadTests.Every_enum_member_is_either_served_or_refused move to the new
Sql.Common.Tests under the same names. SqlServer integration tests get mechanical renames
only. Test-name set across the three projects is identical to the baseline (160 tests).
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
Joseph Doherty