- ScriptLogRateLimiter.LimitPerWindow. The ScriptLogTopicSink and
VirtualTagActor summaries now print the configured limit, not
DefaultLimitPerWindow. Tests assert "limit N/window" for a non-default
N.
- CalculationDriver.Dispose cancels, then takes _evalGate (bounded 2 s)
and disposes the gate and _evalCts. The pump and timer ticks enter the
gate through TryEnterEvalGateAsync, which stops cleanly once the
driver is disposed. Test: Dispose with a 6 s runaway run in flight
returns promptly, disposes both, and a late trigger is harmless.
- ScriptedAlarmEngine captures _shutdownToken once and disposes
_shutdownCts in Dispose when every drained task has completed. A task
stuck past the grace leaves the CTS to the GC. Lifecycle tests assert
the disposal.
- DraftValidator: CalculationNoEffectiveTrigger is skipped for a
change-triggered tag whose scriptId does not resolve. That case is
already CalculationScriptMissing or CalculationScriptNotFound, and
there are no reads to count. Both existing tests now assert the
absence (red before the change).
- docs/VirtualTags.md: System.Threading is denied as a whole namespace,
with an allow-list; the type list is now accurate (Unsafe,
RuntimeHelpers, and the ForbiddenMembers on System.Type); the resource
limits section covers the run guard and the allocation budget.
docs/ScriptEditor.md: accurate deny-list and a new "Runtime safety"
section covering timeout, refusal, quarantine after 3 timeouts,
allocation budget, lifting, and rate-limit summaries that appear only
on the source's next entry after a burst then quiet.
Refs #734
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
DependencyMuxActor retained the last value of every ref ever registered,
and never removed the entries. The continuous-historization recorder
registers every historized ref, so on a historizing node the map grew
with the historized address space and never shrank. The class remark
claimed a bound that did not hold.
- Retain only refs that at least one subscriber registered with
ReplayRetained: true names (VT actors, the Calculation mux adapter, the
scripted-alarm host). A non-opting subscriber is still delivered to but
retains nothing.
- When a ref's last replay-opting subscriber leaves, its value is kept
for a grace (default 2 min, Props(retentionGrace)) so a restart
(old adapter gone, new one not yet registered) still replays. A
periodic sweep then drops it along with the entry. Entries with no
subscriber and nothing retained are removed.
- New SourceRemoved(DriverInstanceId) evicts the values a removed driver
produced, so its last Good is never replayed. The mux records the
publishing driver per retained ref. No production sender exists yet:
DriverHostActor is outside this lane (follow-up).
- Remark rewritten. Tests: retention bounded to replay-opting refs,
release after grace (with an in-grace replay as the positive control),
SourceRemoved eviction, and the restart-replay scenario still green.
Refs #734
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
- I1 ScriptRunGuard: a run refused because the previous one is still
executing is a Bad publish plus otopcua.script.run_refused, and no longer
a quarantine strike. Only a timeout (and an allocation breach) counts;
a refusal neither adds to nor resets the timeout streak; a completed run
(value or throw) resets it. On a 1 Hz trigger with a 2 s budget a single
4 s overrun is one timeout plus two refusals and must not quarantine.
Tests updated across the guard, the alarm engine, the Calculation
evaluator and the VT evaluator, plus
Refusals_neither_count_toward_nor_reset_the_timeout_streak.
- I3 ScriptedAlarmEngine: the quality bucket is tracked only after the
predicate completes (or in the inputs-not-ready path), so the tracked
bucket is the last one annotated. A refused or quarantined predicate
used to re-track the input bucket Good before the attempt and then flip
it Bad, emitting QualityChanged on every push. The run-guard tests now
count emissions (exactly 1 across N pushes, refused and quarantined
cases), with a healthy sibling's dispatch count as the positive control
that every push was processed. Both were red before the fix.
Refs #734
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
- RunWriteAsync wraps the invoker call in WaitAsync(writeTimeout) (Props,
default 10 s = 2x the 5 s write cap): a token-ignoring hung write now
answers BadTimeout, releases its slot and tag, and its orphan outcome
is observed and discarded - later writes to that tag reach the device.
- WriteCompleted carries the launching incarnation (from the process-wide
generation source); a late completion from a previous incarnation after
a supervision restart is ignored instead of freeing the new
incarnation's slot/tag.
- Test: a hung token-ignoring tag-a write is abandoned and a later tag-a
write reaches the device while the abandoned one is still inside it.
Refs #731
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
- GatewayHistorianDataSource.ReadRawWindowAsync keeps the cap + 1 probe budget
(budgetCap) separate from the client's cap: a strict-ceiling or crowding
refusal now reports Limit = the server cap that applied and advises setting
NumValuesPerNode at or below it (it said "lower NumValuesPerNode" with
Limit = cap + 1 to a client that sent 0).
- Fuzz: the oracle-source over-cap assertion was vacuous (cap 0 never counts);
it now checks no reverse window reached the forward-only shape. Class docs
name the post-floor cap set (3 ... 1000) and distinguish NumValuesPerNode
1 / 2 from the smallest server cap.
- HistoryPaging.IsFullPage doc says it judges the REQUEST cap (page + ties +
lookahead), which is finite under any limit; AdvertiseMaxReturnDataValues
swallows any exception (returns false for the caller to log), as its doc
promised.
Refs #736
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
- Writes: a second write to a tag already inside the driver waits in the
queue behind it (_tagsInFlight) while other tags still run under the
cap of 4; queued writes are stamped and failed BadTimeout at dequeue
once older than the 8 s host Ask budget (Props queuedWriteBudget)
instead of being written late.
- Initialise attempts are bounded pessimistically (initializeTimeout,
default 30 s = 2x Tier C) on top of the invoker's token-only timeout:
an overrun is logged as abandoned, reported InitializeFailed so the
retry loop continues, and its late result is dropped by generation.
Generations come from a process-wide Interlocked counter so a prior
incarnation's late result cannot collide (F6).
- PostStop shares one shutdownTimeout budget across shutdown + dispose.
- TelemetryDialSupervisor cancels the establishment deadline on
StreamStopped; FleetDiagnosticsClient builds the ActorSelection inside
the try (a malformed node degrades to "unavailable"); the diagnostics
page labels the column "Last health publish".
- Tests: same-tag serialisation with a distinct-tag positive control;
stale queued write BadTimeout; token-ignoring hung init -> later
attempt connects; stopwatch assertion demoted to a ceiling.
Refs #731
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
- R02:H1 ScriptedAlarmHostActor gains a factory Props
(Func<(upstream, engine)>) so every incarnation builds and owns its own
engine; a supervision restart no longer re-creates the actor around a
disposed engine. The legacy instance-taking Props stays source-compatible
and is now restart-safe in the weaker sense (PreRestart marks the stop as
a restart, PostStop then detaches instead of disposing). DriverHostActor
still spawns through the legacy overload (not owned by this lane — F3).
- R02:H3 OnAlarmCommand runs every engine op under a 10 s token linked to
the actor's lifetime (DefaultCommandTimeout / Props commandTimeout) and
logs a Warning on timeout instead of suspending the mailbox on a stalled
store.
- R02:L3 DependencyMuxTagUpstreamSource.RetainOnly(loaded dep-ref union),
called after every successful load.
- R02:P6 VirtualTagActor's per-failure ScriptLogEntry is rate-limited per
tag (ScriptLogRateLimiter, 20/min + one summary); the Bad publish and the
metric are untouched.
- R07:H6 DependencyMuxActor retains the last (value, status, ts) per
ever-registered ref (through unregisters) and replays them in one batch to
a RegisterInterest(ReplayRetained: true) — VirtualTagActor, the Calculation
mux adapter and the alarm host opt in; the historization recorder does not
(a replay there would record a stale sample per deploy). CalculationDriver
records inputs regardless of _running so a replay landing before
InitializeAsync still satisfies the change-gate.
- R07:P4 CalculationEvaluator negative-caches compile failures by source
hash (one Roslyn attempt + one Warning per source until redeploy); the
driver's script-log entry fires on the Good→Bad transition or a change of
reason, matching the once-per-transition Bad publish.
- R07:H8 array results dedup structurally.
- R07:L2 ShutdownAsync drops the compiled scripts (collectible ALCs).
- R07:U5 DraftValidator rule CalculationNoEffectiveTrigger: a tag with no
timer whose change trigger is off or whose script has no literal
ctx.GetTag read can never evaluate.
Refs #734
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
- R05:1/12 ScriptedAlarmEngine: _valueCache is cleared in LoadAsync (it is
re-seeded for the referenced paths) so retired tags no longer accrete across
deploys; OnUpstreamChange no longer writes the cache after Dispose.
- R05:3 ScriptedAlarmEngine.Dispose drains in-flight work for at most 5 s
(DisposeDrainTimeout), then cancels it through a shutdown token every
DrainDirtyAsync/ShelvingCheckAsync now runs on, logs a Warning and gives
one second of grace — a stalled IAlarmStateStore.SaveAsync can no longer
hang host shutdown. A save that completes inside the bound is still drained
(positive control test).
- R05:6 ScriptedAlarmSource logs a throwing OnAlarmEvent subscriber at
Warning (naming the alarm) instead of swallowing it.
- R05:7 LocalDbStoreAndForwardSink keeps a cached dead-letter counter in step
with every dead-letter/revive/purge path and resyncs it with the queued
counter on the same cadence; GetStatus no longer runs a COUNT(*) scan.
- R05:9 ScriptLogRateLimiter (20 per source per minute, fixed window, one
summary entry naming the dropped count when the window rolls) behind
ScriptLogTopicSink (key = script|vtag|alarm) and ScriptLogCompanionSink
(key = script name).
Refs #734
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
- NodeManagerHistoryReadRawCapFuzzTests: 10k seeds (env OTOPCUA_PAGING_FUZZ_ITERATIONS)
through a real SDK node manager against wire-faithful fakes of SqlServer / QuestDB /
Gateway that enforce the backend half of the cap; random series with ties, random
windows (empty, on/past a tie, between samples, forward/reverse/end-only, bounds),
N in {0,1,2,small,huge}, cap in {off,3..1000}, tie budget {3,8,65536}. Pages must
concatenate to the cap-off one-shot answer (checked against the series), terminate
within values + 2 (+ one empty step per oversized boundary cluster), never exceed
the cap, never ask the backend for 0 / over-cap; refusals only past the budget.
- HistoryPaging.AdvertiseMaxReturnDataValues writes HistoryServerCapabilities/
MaxReturnDataValues (i=11273), read back through the SDK master node manager.
- MinMaxRawValuesPerRead raised to 3: at 2 a resumed page has no room (value + its
boundary tie + lookahead) and every value cost an empty page + CP (seed 15).
- RawPageLimit rows pin the default-cap arithmetic (9 999 first page, 9 998 resumed).
Fuzz findings recorded as follow-ups: a bounded read whose data fits one page
returns cap + 1 (end bound fitted against N, not the cap; node manager, F2);
the Gateway walk-back's cost on a sparse series under a tiny tie budget is
pre-existing (seed 320: 82 reads uncapped, 93 capped).
Refs #736
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
DriverInstanceDiagnostics.Name carries the string driver-instance id
(what /hosts, telemetry and the artifact key on) and DriverInstanceId
the DB row Guid; the wire record has no slot for the authored display
name. The write-cap test asserts entry order per slot pair instead of
completion order of two concurrent writes.
Refs #731
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
R05:10 — the namespace deny-list covered System.Threading.Tasks but not
System.Threading, so SemaphoreSlim / Monitor / SpinWait / Mutex /
EventWaitHandle could park a script's pool thread past its budget (or touch a
system-global kernel object); System.Type.GetType(string) / GetMethod* /
InvokeMember and System.Runtime.CompilerServices.RuntimeHelpers resolved and
reach a forbidden type without naming it syntactically.
ForbiddenTypeAnalyzer now denies the whole System.Threading namespace with a
type-granular allow-list (CancellationToken, Interlocked, Volatile — the
sync-free primitives), adds a member deny-list for System.Type's reflection
entry points (GetType/GetMethod(s)/InvokeMember/GetProperty(ies)/GetField(s)/
GetMember(s)/GetConstructor(s)/GetEvent(s)/GetDefaultMembers; instance
object.GetType() stays allowed) and puts RuntimeHelpers on the type deny-list.
Thread/ThreadPool/Timer leave the type list — the prefix rule reaches them.
R05:11 — the allocation budget landed with E1's ScriptRunGuard
(Scripting:MaxAllocBytesPerRun, default 64 MB): sampled around each run,
breach quarantines. It is observation after the fact; a pre-emptive OOM guard
still needs an out-of-process runner (follow-up issue in the lane report).
The Monaco editor shares the analyzer, so DiagnoseTests pins every new form
as an OTSCRIPT_FORBIDDEN marker and every allow-listed form as clean.
Refs #734
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
DriverHostActor wraps the health publisher it hands its children in a
ChildHealthLedger (last snapshot per driver id, forwarded to the real
publisher), so GetDiagnostics now answers with each child's row id,
authored name, last-published state, device counts (host statuses when
the driver probes hosts, else one device) and last-change time — instead
of Guid.Empty / "Spawned" / 0 / now. Entries are forgotten on StopChild
and operator Restart.
IFleetDiagnosticsClient gains its first consumer: the new
/fleet/diagnostics page (node selector + ?node= query, revision,
running-from-cache notice, per-driver table). FleetDiagnosticsClient
logs the degrade-to-empty path at Warning.
Review ref: 02/U1.
Refs #731
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
A timed-out script is abandoned, not stopped, and every seam re-ran it on the
next trigger, leaking one pool thread per trigger (R03:1.1, R05:2, R07:L1).
A shared ScriptRunGuard, keyed per script instance, now:
- refuses a run while that script's previous orphan is still executing
(Bad "previous evaluation still running" + otopcua.script.run_refused);
- quarantines after 3 consecutive non-completions or an allocation-budget
breach (sampled with GC.GetAllocatedBytesForCurrentThread; default 64 MB):
no further dispatch, Bad quality, one Error, otopcua.script.quarantined,
cleared on source change / redeploy / reset;
- starts the budget clock when the pool picks the run up, so starvation is
no longer charged to the script (R07:P5), and cancels the evaluator token
on timeout.
Wired into RoslynVirtualTagEvaluator, CalculationEvaluator (new async
EvaluateAsync; the driver's pump and timer ticks now await the run behind a
SemaphoreSlim gate) and ScriptedAlarmEngine (a non-completing predicate
holds state and annotates the condition BadInternalError). ScriptingOptions
(Scripting:MaxAllocBytesPerRun, Scripting:QuarantineAfterConsecutiveTimeouts)
carries the knobs; the Calculation driver config accepts the same two keys.
Tests: guard unit suite (incl. the 30-trigger runaway leaving one orphan with
a healthy sibling as positive control), per-seam refusal/quarantine/reset
tests. The S12 race test now uses one vtag id per loop: twelve concurrent
evaluations of ONE id is a shape production never produces and the guard
refuses by design.
Refs #734
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
CallTimeoutSeconds was bound, defaulted and documented but consumed
nowhere. TelemetryDialSupervisor now arms a per-generation deadline on
every dial: a dial that has delivered no event by the deadline is
cancelled and treated as a transport failure (reconnect with a failure
streak). A live node replays its snapshots on subscribe, so this bites
only a dial that never connects (a black-holed host, where the socket
connect has no timeout). An established stream is deliberately not
bounded — the wire has no heartbeat, keepalive pings own its liveness.
Review ref: 02/U2.
Refs #731
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
- DriverHostActor.StopChild removes the driver's _lastReprovisionUtc stamp
(and its deferred-reprovision timer): the map grew per removed id and a
re-added driver inherited a backoff it never earned (02/L2).
- Stale now registers explicit drops for AttributeValueBatchPublished,
AttributeAlarmPublished, ArtifactForApply and ApplyWedged instead of
letting them hit Unhandled (02/H5).
- DbHealthProbeActor runs its SELECT on the thread pool and pipes the
outcome back (single-flight), with a 2 s command timeout on relational
providers, so a hung SQL Server no longer pins the actor thread and the
cached GetStatus answer stays reachable (02/P7).
- TelemetryLocalHub eviction tombstones are timestamped and swept past a
10 min TTL on the next Evict; a TimeProvider ctor is the test seam (02/L4).
- Tests: ValuePublishes.Single helper replaces the per-value
AttributeValuePublished in CalculationDependencyFlowTests (02/U4, test
half; the production receive is owned by Lane E).
- R05/8 audit: PollGroupEngine.Unsubscribe has no production caller; every
driver already uses UnsubscribeAsync (no change).
Refs #731
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
WriteAttribute was a ReceiveAsync, suspending the child's mailbox for the
whole device round-trip (up to 5 s): writes serialised, the second of two
operator writes to a slow device missed the host's 8 s Ask and was
reverted although the device took it, and every data change queued behind
the write. Writes are now a synchronous Receive that launches the device
call on the thread pool (sender captured, reply from the task, slot freed
by a self-sent WriteCompleted) under a per-driver cap (default 4; excess
writes queue in order). Queued writes fail fast on every exit from
Connected. Subscribe/unsubscribe stay ReceiveAsync.
Review ref: 02/P2.
Refs #731
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
Review R08:1.1: an uncapped HistoryRead-Raw (NumValuesPerNode = 0) read a
tag's whole window into memory on every backend (SQL TOP(int.MaxValue),
QuestDB LIMIT, Gateway max_values = int.MaxValue + a second snapshot copy).
New ServerHistorian:MaxRawValuesPerRead (default 10 000; <= 0 unbounded with
a Validate() warning; 1 raised to 2). Each backend data source takes it,
reports it as IHistorianDataSource.MaxRawValuesPerRead (the Gateway: min
with a strict gateway's learned ceiling), so the node manager's existing
RawPageLimit paging serves N = 0 and N > cap as pages of at most the cap
with a continuation point. Independently, a backend raw read asking for 0
or more than the cap reads cap + 1 rows and is REFUSED
(HistoryReadLimitExceededException => BadTooManyOperations) when the window
holds more - never answered truncated, since the server's paging reads a
short answer as the last page. Bound through the Host registry, the
SqlServer/QuestDb providers and GatewayHistorian.CreateDataSource.
Tests: options (default/binding/warnings), provider binding, Gateway unit +
through a real SDK node manager (uncapped -> 999/998/998/605 + CPs), and a
conformance case for the SQL backends.
Refs #736
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
The Reconnecting retry timer started a new ShutdownAsync + InitializeAsync
pair on every tick whether or not the previous attempt had finished; the
generation token only discarded the older RESULT, so with an Initialize
bound longer than the cadence the teardown ran underneath an attempt still
inside the driver (the dispose-before-overwrite race). An _initInFlight
gate, cleared by the piped InitializeSucceeded/Failed, skips a tick while
an attempt is running; the pre-reconnect teardown is bounded by the
shutdown timeout; PostStop cancels an in-flight attempt before shutting
the driver down.
Review ref: 02/H2.
Refs #731
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
DriverInstanceActor.PostStop now bounds IDriver.ShutdownAsync by a
shutdownTimeout (default 5 s, logged on overrun) and then disposes the
driver (IAsyncDisposable preferred, else IDisposable) — but only on a
real stop. PreRestart flags the restart so the PostStop it triggers
skips the dispose, because a supervision restart re-uses the same
driver object (Props closure) and the host re-initialises it.
DiscoveryDriverBrowser disposes its throwaway capture/probe driver
after the bounded shutdown, including after a failed or timed-out one.
Review refs: 02/L1, 02/P4, 06/G-1 (host context), 07/L2.
Refs #731
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
The #687/F4 crowding re-read doubled its room up to 8 re-reads with no cap, so a pathological single-ms
cluster on a streaming gateway was streamed several times over for one page. The room is now capped at
ServerHistorian:MaxTieClusterOverfetch (plumbed into GatewayHistorianDataSource as maxPreWindowRows,
default 65536); past it, or once a read has already seen more, the read is BadTooManyOperations with
PreWindowRows set.
Item 1: IHistorianDataSource.MaxRawValuesPerRead (Gateway: learned ceiling - 16 = L; 0 elsewhere, guard-tested).
RawPageLimit plans every raw page on top of #692's lookahead: with L > 0 the read (page P + boundary ties k
+ lookahead) is <= L, P = min(N, L - k - 1) (uncapped: L - k - 1); no room => straight to the tie-cluster
over-fetch (never an uncapped or underflowing request). One re-plan + re-read when the read taught a new
limit or was refused for crowding pre-window rows (HistoryReadLimitExceededException.PreWindowRows): the
page shrinks by them. Over-fetch bound min(MaxTieClusterOverfetch, L - 1); slice size never 0.
Review fixes: F1 a window starting at/before the epoch counts AVEVA's synthetic row as pre-window (a
ceiling-truncated read was reported complete); F2 the page path disables ReverseRawReader's own re-run
(cold end-only ceiling 20/N=3000 cost 3,023 reads, now <= 40); F3 crowded look-back re-read around, not
refused; F4 the #687 crowding re-read room at least doubles (up to 8 re-reads), so a cluster of hundreds
just before a resume point no longer fails on a default gateway; a crowding refusal that leaves no room
is BadTooManyOperations, never a tick-by-tick cursor.
Item 2: ServerHistorian:EventReadHorizon (default 00:00:00 = exact, unchanged). When set, every fresh
HistoryReadEvents window's earlier bound is raised to now - horizon (both directions, all backends).
Lossy by design; documented.
Item 3 (native TimeAverage/Total re-check) stays blocked on historiangw#27.
A time inside a gap of a bursty tag costs a 64-row jump read landing in the next
burst plus a bisection back across the gap (~6 reads), so the 64 + 4/time cap
refused a 1 h/day 1 Hz tag asked at noon on 30/100/300 consecutive days
(186/606/1,806 reads) that AVEVA's own AtTime served. The cap is a runaway guard
(HistoryReadDeadline bounds wall clock): now 64 + 16 per distinct time.
Regression tests for x30/x100/x300 (each <= 7 reads a time, values checked).
Docs: DateTime-hinted nodes are stepped but keep the gateway's Double (the
Gateway never historizes DateTime nodes; the SQL backends return DateTime).
H1: the walk-back reset its width after a full segment and discarded a full
whole-remainder read, so a dense tag that stopped reporting weeks ago gave up
after 65 reads (BadTooManyOperations). It now gallops (x4, whole-remainder read
after two empties) and then BISECTS once any stored row is known below — a full
segment's (incl. a full whole-remainder read's) last row, or an earlier window
read's last row: (mid, hi] empty => hi = mid; full => known = its last row;
complete with rows => done; one density-aimed segment after a full read until an
aimed segment comes back empty; below 2 ms the whole stretch from the known row
(never a 100 ns step). Stopped 1 h..365 d with 5 y history: 6-18 reads at
1/min, 21-25 at 1 Hz, 25-31 at 10 Hz.
M1: a jump read asks for 64 rows (1,000 times over 10 y: ~66k rows, was ~1M).
L1: per-request read cap 64 + 4 x distinct times with a clear message; a strict
ceiling below 4 rows is refused naming the ceiling.
L2: DateTime hints are stepped. L3: under an integer hint a NaN/inf or
out-of-Int64-range value is unusable, never saturated Good.
L5: conformance Int64 AtTime asserts the type. L4: docs name the backend
differences. Nit: the window read end is clamped to now + 1 day.
Reviewer harnesses (Scratch693Fuzz/Cost, not committed): 0 differential diffs
over 2,400 cases.
F1 (pre-existing): SliceTieCluster continued a forward read while next <= endUtc, but the
forward window is end-exclusive; an oversized cluster one step below EndTime resumed AT
EndTime, the resume became a start == end point read and returned the EndTime samples as
data (microsecond: EndTime 8.1 us truncated to 8.0). Continue only while next is strictly
before EndTime truncated to the backend resolution.
Tests: A_tie_cluster_just_below_the_end_time_never_resumes_onto_the_end_time (native +
microsecond; both fail on the old rule) and
A_cursor_inside_a_tie_cluster_over_fetches_without_a_normal_read_first (pins the
WithinTieCluster shortcut by per-page read count; fails with the shortcut disabled).
Docs: the oversized-cluster exception to 'every page full / no lookahead => last' (F2),
and the N + skip + 1 strict-ceiling edge note referencing #694 (F4).
Review follow-up: on the Gateway every value is a Double (AVEVA stores a Boolean
as a 0/1 Int2), so the raw-evaluated AtTime interpolated a Boolean node to 0.5.
- IHistorianDataSource gains a default-interface overload
ReadAtTimeAsync(fullReference, timestamps, TypeCode? valueType, ct) that
forwards to the existing one (SqlServer/QuestDB/Null/fakes unchanged).
- OtOpcUaNodeManager.HistoryReadAtTime passes the node's scalar DataType
(AtTimeValueType: built-in type -> TypeCode; arrays/other types => null);
Raw and UNS NodeIds alike.
- GatewayAtTimeReader converts each raw row to the hinted kind BEFORE the shared
AtTimeEvaluator runs (Boolean = value != 0 => stepped; integers => Int64 =>
interpolated, rounded half away from zero, returned as the node's integer
type; floats Double), so the evaluator's own type branch decides.
- AtTimeEvaluator boxed every interpolated Int64 as a Double (`cond ? (long)x :
v` widens to double); its "keeping its type" test passed because Shouldly
ShouldBe compares numbers across types. Fixed (affects SqlServer/QuestDB too)
and pinned with ShouldBeOfType.
A resumed raw page asked the backend for only N rows from the boundary timestamp
(inclusive), then trimmed the boundary ties already emitted: it netted N - skip values,
and at N = 1 nothing — the empty "full" page was taken for a stalled tie cluster and a
MaxTieClusterOverfetch + 1 (65,537-row) over-fetch stepped one tick, returning an EMPTY
page with a continuation point between every value (8 values = 17 pages / 25 reads),
forward and reverse, with or without ReturnBounds, on every backend.
Each page's read now asks for N + boundarySkip + 1 rows: the ties it trims, the page and
one lookahead row. The lookahead row is the 'more data' signal, so an exact multiple ends
on its last full page (no trailing empty page). The over-fetch fires only when every row
past the trimmed ties is still on the boundary (a genuine cluster larger than the page);
a cursor left inside a cluster is flagged WithinTieCluster and over-fetches directly.
A page that never leaves the boundary adds the prior skip to its cursor.
Low items: BoundedReadHasAnythingAsync carries its walk hint and, when there is no data,
the end bound it found (HistoryEndBound.Resolved + DataExhausted), so the next page reads
nothing; HistoryBounds.IsPlaceholder is an explicit marker (ConditionalWeakTable over the
NotFound instances) instead of status+null shape, so a stored Bad_BoundNotFound row is data.
Tests: NodeManagerHistoryReadPageFillTests (N=1 every shape/direction/bounds, tie clusters
straddling boundaries at N=1/2/3, exact-multiple, carried end bound + walk hint, stored
placeholder-shaped row). Existing paging tests updated where they encoded the short pages.
Gateway HistoryRead-AtTime passed AVEVA's own interpolation through: live it
answered the previous value as Good at a stored NULL's own time, null + Bad at
a Good sample right after a NULL, a drifted 99.99999999944 for a stored 100,
and no Interpolated bit. It is now served from raw gateway reads and evaluated
with Sql.Common's AtTimeEvaluator, as the SQL backends do (Part 11 §6.5.4).
GatewayAtTimeReader: one <=1,024-row forward window read [first-1ms, last+1ms]
for the batch, a walk-back (density-seeded, x4 growth, whole-remainder shortcut,
bisects dense history) for the first time's prev, and an 18-row probe for the
last time's next; truncated window reads continue or jump with a density-sized
margin. All bounds whole ms; a row counts only strictly inside its request
(AVEVA's boundary row never a sample); Bad rows value-less (#690); never past
now + 1 day; strict-gateway ceiling learned (#691.3) without re-probing.
10 dense times = 1 read (exact) / 3 (interpolated); 10 hourly = 12.
Kill switch ServerHistorian:GatewayAtTimeFromRaw (default true; false = the
old AVEVA passthrough). Known limit: the wire carries no data type, so numeric
tags interpolate as Double (Boolean/integer nodes are not stepped/rounded as on
the SQL backends).
1. The at-or-after bound read on a forward-only backend (Gateway) ends at
now + ReverseRawReader.LookAhead instead of DateTime.MaxValue (the gateway
only checks start <= end, so a year-9999 end reached AVEVA); a bound beyond
the horizon is not found without a read. SqlServer/QuestDB keep MaxValue:
they bind it safely and may hold samples further ahead. The Gateway fake now
refuses far-future ends, so the missing-end-bound test is no longer vacuous.
3. No data and no bound found (whole read empty) => GoodNoData, no values —
the pre-bounds answer (6.5.3.2: success only if one or both bounds exist).
A one-value page whose start bound is missing first checks there is data or
a found end bound.
4. ServerHistorian:HonorReturnBounds (default true); false ignores ReturnBounds
as before #691, including the modified-read Bad_InvalidArgument.
The start bound is the stored prior sample at its own time (walked back), never
the synthetic boundary row stamped at the query start; a stored NULL is a Bad
bound; reverse end bound walks back too.
The node manager composes the start/end bounds from each backend's existing raw
reads (one authority, HistoryBounds): at-or-before = a capped reverse read
(native, or ReverseRawReader's walk-back on a forward-only backend — never
AVEVA's synthetic boundary row), at-or-after = a capped forward read. Bounds
count toward NumValuesPerNode, the start bound leads the first page, the end
bound ends the last (carried in the continuation point). Missing bound =
Bad_BoundNotFound (null, at the bound time; one-sided reads ±1 s from the
previous value, Table 1 footnotes a/b). A modified read with ReturnBounds is
Bad_InvalidArgument (Part 11 6.5.3.3).
The .NET SDK's ReadRawModifiedDetails defaults ReturnBounds to TRUE; the
existing tests built details without setting it and now set it false.
Oracle: every row of Part 11 Table 1 over three backend shapes, plus paging
concatenation, ties, Bad bounds, microsecond truncation; conformance pins the
lookup primitives on SqlServer + QuestDB.
A tie cluster's truncated read left the width at one tick; once the gap
above it was under two milliseconds nothing floored it, so segHi
stepped down one tick per read: 30 rows at one ms 0.3 s below hi with a
carried 1 s width took 10,006 identical reads (S8). (a) The top-anchored
width is floored at the granularity, Min kept; (b) a segment no wider
than the granularity is the unit that escalates to
MaxTieClusterOverfetch and then refuses - per millisecond, exact for the
ms-resolution Gateway (documented). Both are needed: the floor alone
loops on crowded reads with a small tie budget. S8 is a repo test
(4 shapes, reads <= 30, 0 repeated requests); random-data tests now
measure the refusal unit as rows in any 1 ms window. Reviewer harness,
5,000 seeds x default/MSONLY/CROWD: worst page 70 reads (default/MSONLY),
63 (CROWD) at M=65536, p99.9 27-37; no page over 500 reads at any tie
budget.
The null source has no history in either direction; reporting false
made the server walk an empty reverse events read back through three
empty forward reads. It now answers the reverse overload with the empty
result itself (guard test unchanged: it still declares both members).
Bisecting the gap above a truncated read halved below the 1 ms request
granularity (requests are ms-rounded, so it re-sent identical requests)
and bisected the WHOLE gap even when the burst ended right above the
row it saw: a 1,026-row burst ending 100 days ago took 46 reads. After
an empty top-anchored segment the walk now gallops up from the known
row ((known + d, top], d x4, following each truncated read), then
bisects the bracket, with halving floored at the granularity (the Min
kept; a crowded gallop falls back to top-anchored halving). Burst: 18
reads, 0 repeated requests; dense tag stopped 2 days ago: 26 (gallop
alone crawled: 94). Walk fuzzed at 4,000 seeds locally (400 in-tree).
Docs: measured counts; CLAUDE.md gateway prerequisites list
RuntimeDb:EventReadMaxRows.
Joseph Doherty