When the historian is reached through a port-forward whose local port differs
from the server's real service port, WCF's server-side AddressFilter rejects the
message (To = tunnel port != server port). ConnectViaAddress lets the channel
connect to the tunnel while addressing the SOAP To the real Host/Port endpoint.
Applied in HistorianWcfClientCredentialsHelper.Configure (the critical event
factories already call it). The C2 spike reads HISTORIAN_WCF_EVENT_VIA.
Claude-Session: https://claude.ai/code/session_012SDSQ3AcaXqPcBtDESBRii
The first live run used the wrong port (32568 direct vs the 42568 WCF tunnel) and
hardcoded RemoteTcpIntegrated; via the tunnel the error advanced from socket-RST
to ProtocolException (binding/security mismatch). Add HISTORIAN_WCF_EVENT_TRANSPORT
(certificate), _DNSID, _ALLOW_UNTRUSTED, and an opt-in _VERBOSE for live binding
diagnosis. Default output stays sanitized; still Windows-only, never fails the suite.
Claude-Session: https://claude.ai/code/session_012SDSQ3AcaXqPcBtDESBRii
The gRPC ReadEvents throws no longer advise "use the WCF transport for event
reads": that path is moot on 2023 R2 (net.tcp is reset at the framing layer,
live-disproven 2026-06-25). Messages now state event reads are auth-solved but
server-gated over gRPC and have no WCF fallback on 2023 R2, citing the two
evidence docs. WCF orchestrator remarks scoped to legacy 2020 historians; row
layout noted as decoded. String/comment only; throw behavior unchanged.
Claude-Session: https://claude.ai/code/session_012SDSQ3AcaXqPcBtDESBRii
WCF net.tcp (RemoteTcpIntegrated) against the live 2023 R2 historian is reset
at the socket-write/framing layer before any auth — both the event spike and a
basic Probe/ReadRaw throw the identical CommunicationException/SocketException
("forcibly closed by the remote host"). The 2023 R2 box does not serve the
legacy WCF transport; C2's "route via WCF" unblock is moot on this server class.
Sanitized: counts + native return codes + buffer lengths only.
Claude-Session: https://claude.ai/code/session_012SDSQ3AcaXqPcBtDESBRii
Int8/UInt8 analog tag-create + historical-value write encoders un-gated and
live-proven; golden-pinned. UInt1 attempted but re-gated — the historian stores a
degenerate UInt1 analog tag. 2023 R2 gRPC interface-version integers captured (C3a).
Claude-Session: https://claude.ai/code/session_012SDSQ3AcaXqPcBtDESBRii
Removes the stale UInt1 → UInt8(1) entry from the EncodeNativeValue layout
table (UInt1 is re-gated; the prose already said so). Int8/UInt8 layout note
updated from "pending" to live-proven.
Claude-Session: https://claude.ai/code/session_012SDSQ3AcaXqPcBtDESBRii
EnsureTagAsync + AddHistoricalValues now cover Int8/UInt8 (codes 0x19/0x39, native
LE int64/uint64 value). UInt1 documented as not-supported: the server stores a
degenerate analog tag (GetTagInfo stub, type byte 0x00).
Claude-Session: https://claude.ai/code/session_012SDSQ3AcaXqPcBtDESBRii
Live evidence: EnsureTags(UInt1) returns success but the server stores a
degenerate tag (descriptor type byte 0x00, no GUID/name), so GetTagInfo
truncates and writes fail. Not client-fixable on the analog path. Int8/UInt8
stay GREEN (live-proven). UInt1 reverts to ProtocolEvidenceMissingException
(fail-closed); golden rows removed; negative-gate tests added. Removed the
one-off capture diagnostic.
Claude-Session: https://claude.ai/code/session_012SDSQ3AcaXqPcBtDESBRii
Env-gated live evidence test reads History/Retrieval/Transaction/Status
GetInterfaceVersion over gRPC; integers recorded in grpc-interface-versions.md.
Stale not-yet-captured comment fixed; gate XML-doc notes live confirmation.
Claude-Session: https://claude.ai/code/session_012SDSQ3AcaXqPcBtDESBRii
New InlineData rows derived from the captured Double baselines (type-code /
value bytes swapped). Negative-gate tests retained for still-gated types.
Claude-Session: https://claude.ai/code/session_012SDSQ3AcaXqPcBtDESBRii
Track A (tag-client …OnSession seams + HistorianSession browse/metadata), the GREEN
event-session reuse spike (B0), and the HistorianEventSession primitive. Live-validated.
Claude-Session: https://claude.ai/code/session_012SDSQ3AcaXqPcBtDESBRii
The Q3 read-after-send probe (ReusedEventSession_ServesReadAfterSend_BestEffort)
long-polled GetNext to the no-data terminal with no tight bound and ran past the
5-min suite timeout on the live run. Bound it two ways: a read-only options copy
with a 5s RequestTimeout (so each GetNext RPC deadlines fast) and an 8s
CancellationToken passed as ct. Either fuse returns the method in ~10s; the
timeout/cancellation is logged as the expected C2-gated outcome (still no assert).
Other three spike methods unchanged.
Claude-Session: https://claude.ai/code/session_012SDSQ3AcaXqPcBtDESBRii
Extract SendEventOnSession (and best-effort RunEventQueryOnSession) so the B0b spike
can run multiple event ops on one already-opened v8 Event session. RegisterCmEventTag
made independently callable. Behaviour-preserving (pending.md A1 broadening, Stage B0).
Claude-Session: https://claude.ai/code/session_012SDSQ3AcaXqPcBtDESBRii
Item 3: the gRPC read-back against the live 2023 R2 server proves the SDK-sent
event PERSISTS (independently read back from event history), resolving the older
WCF/M2 caveat ("server accepts AddS2 but the local dev box does not persist to
v_AlarmEventHistory2") as an environment artifact, not an SDK gap. Also retire the
stale "fresh native capture (SendEvent gRPC framing)" next-step note — SendEvent
over gRPC is now shipped + live-validated.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B6mcaT2PjRFKcogzp9UkfC
Add SendEventAsync to the write surface: M2 event-send, now on both transports.
WCF runs Open2 event-mode -> CM_EVENT registration -> AddS2; gRPC runs v8 Event
OpenConnection -> registration -> HistoryService.AddStreamValues. Both carry the
same "OS" event VTQ buffer (no distinct event RPC, not the "ON" historical buffer);
gRPC path live-validated end-to-end. Only original events with string properties.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B6mcaT2PjRFKcogzp9UkfC
Tested the binary-dive "use deleteFromServer=true" hypothesis directly against
the native client (local 2020 WCF box, Capture-DeleteTagExtendedProperties.ps1
cross-session sync trick). Result: the native DeleteTagExtendedPropertiesByName
with deleteFromServer=true returns Success=true, but the property is re-fetchable
and re-deletable across repeated fresh sessions — it is NEVER durably removed.
So the native client itself only performs an optimistic client-side cache delete
the server does not durably honor (the HCAL cache-sync model the decompile shows).
This supersedes the earlier "code=1, prop survives" note (that was the same-session
sync-gate failure; with proper cross-session sync it returns Success yet still does
not durably delete). A managed DeleteTagExtendedPropertiesAsync would return a
misleading success, so it correctly stays unshipped. Handoff item 7 updated.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B6mcaT2PjRFKcogzp9UkfC
Captured the native 2023 R2 client's gRPC event send (new capture-send-event
harness scenario): it rides HistoryService.AddStreamValues with the SAME "OS"
(0x534F) storage-sample buffer the WCF path already uses (HistorianEventWrite-
Protocol) — confirming "no distinct RPC", and that it is NOT the historical
write's "ON" buffer. Diffed the write-enabled vs read-only v8 Event open: byte-
identical apart from per-session crypto, so the existing OpenSession event path
is reused unchanged.
So SendEvent-over-gRPC was pure assembly of proven parts:
- HistorianGrpcEventWriteOrchestrator = v8 Event open + CM_EVENT registration
(UpdC3/RegisterTags/EnsureTags) + AddStreamValues(OS buffer).
- HistorianClient.SendEventAsync now routes to it for RemoteGrpc (WCF otherwise).
Live-validated end-to-end against the 2023 R2 server: pure-managed SDK send →
AddStreamValues BSuccess=true → the event reads back from the server (markers
confirmed in returned event rows). The native gRPC RegisterTags(24B) +
EnsureTags(86B) byte-match our serializers (new GrpcEventSendProtocolTests
golden, closing the 83-vs-86 EnsureTags question). Gated live test
SendEventAsync_OverGrpc_AcceptsEvent (opt-in HISTORIAN_GRPC_EVENT_SEND=1).
331 offline tests pass.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B6mcaT2PjRFKcogzp9UkfC
Mined the full decompiled stock 2023 R2 managed client as the oracle for every
still-pending gRPC item. Governing fact: ArchestrA.HistorianAccess is a C++/CLI
shim into native HistorianClient; the managed Grpc*Client wrappers have zero
call sites, so buffer-building/dispatch for the pending items is native (absent
from the binaries). Sharpened verdicts into handoff.md:
- Items 4/5/6 + OpenStorageConnection: hard-confirmed walled, with real reasons
(SQL gated out client-side via IsManagedHistorian; no Revision RPC in the gRPC
contract; LoadBlocks response is a native blob behind the storage console handle).
- Items 3 (SendEvent) and 7 (DeleteTEP): moved from vague to precise, LOCAL-box
capturable targets (PackToVtq btValues / DeleteTagExtendedPropertiesByName
BtInput with deleteFromServer=true).
Also correct the HistorianGrpcRevisionProbe doc comment: it probes the
non-streamed ORIGINAL-insert path (AddNonStreamValues), a distinct capability
from revision EDITS (native AddRevisionValues trio, no gRPC RPC) — the prior
comment conflated them.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B6mcaT2PjRFKcogzp9UkfC
Bring the doc header current with the merged event-row parser fix: bump
"Last updated" to 2026-06-23 and correct the Build And Test known-good
result from 321/321 to the actual 328/328 (build clean 0/0), noting the
+7 are the HistorianEventRowProtocolTests golden + gated-capture coverage.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B6mcaT2PjRFKcogzp9UkfC
Docs-only. Updates handoff.md item 1 to reflect that all four next-session angles for the
gRPC event zero-rows are tested and ruled out (transport, metadata/cert, topology, data
store) and that the parse path is verified against the provided client with a latent
multi-row bug fixed. Corrects two historical event-row-layout skeletons that described
0x1E as a per-row marker (it is a one-time buffer header field; rows are markerless).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B6mcaT2PjRFKcogzp9UkfC
Updated the live-blocker item (1) to reflect that all four next-session angles for the
gRPC event zero-rows are now tested and ruled out (transport, metadata/cert, topology,
data store) and that the parse path is verified against the provided client with a latent
multi-row bug fixed. Corrected the two historical event-row-layout skeletons that wrongly
described 0x1E as a per-row marker: it is a one-time buffer header field and rows are
markerless (which is why the old parser returned only the first row of any multi-row
buffer, on WCF too).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B6mcaT2PjRFKcogzp9UkfC
Three steps verifying the gRPC event read against the provided 2023 R2 client:
- Decompiled the stock managed client (Archestra.Historian.GrpcClient, HistorianAccess):
confirms no hidden client-side difference. The stock client is gRPC-Web/HTTP-1.1 (same
transport as ours), m_metadata is gzip-only, the ClientInterceptor is a no-op, and it
presents no TLS client cert. The event-query orchestration lives in the native C++ core.
- Captured decrypted HTTP/1.1 frames of a native capture-event (50 rows) vs our SDK (0
rows) through a TLS-terminating tee proxy. Found the native splits services across 5
connections and runs the event query on a dedicated RetrievalService connection; tested
replicating that (HISTORIAN_GRPC_EVENT_SPLIT_CHANNEL) -> still 0 rows, so the server
correlates by session handle, not connection. Topology is not the gate.
- Verified the parse path against the provided client's real result buffer (50 events) and
fixed a latent bug: the event-row buffer is version + rowCount + a one-time 0x1E header
field then MARKERLESS rows; the parser wrongly treated 0x1E as a per-row marker and
decoded only the first row of any multi-row buffer. This also affected the shipped WCF
event read (identical v9 header). Fixed to a 10-byte header + markerless rows, accepting
version 9 (WCF) and 11 (gRPC). The real 50-row buffer now decodes to exactly 50 events.
Net: every client-side angle for the gRPC zero-rows is exhausted (payload, transport,
metadata/cert, topology, data store) -> the gate is a server-internal per-connection
retrieval working-set. The parse path is now verified against real 2023 R2 event data on
both transports, and WCF event reads now correctly return all rows of a multi-row buffer.
gRPC event-row retrieval stays auth-solved / parse-verified / retrieval-server-gated.
328 offline tests pass.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B6mcaT2PjRFKcogzp9UkfC
Used the provided stock client as an oracle to verify the event read path. The
capture-event harness returns 50 real events, and the instrument-grpc-nonstream rewrite
captured the exact GetNextEventQueryResultBuffer.result buffer (63,192 bytes, version
0x0B=11, rowCount 50 = 25 Alarm.Set + 25 Alarm.Clear). Feeding that real buffer through
HistorianEventRowProtocol.Parse exposed a latent parser bug.
The real buffer layout is: version(2) + rowCount(4) + headerField(4, =0x1E) followed by
MARKERLESS rows (rowFormat(2)=7 + filetime(8) + 8x u16 slots + compact-ascii type +
propCount + props). The parser wrongly treated the one-time 0x1E field as a per-row
marker and re-consumed [marker+format] for every row, so it decoded only the FIRST row
of any multi-row buffer and stopped. This is not gRPC-specific: the captured WCF v9
buffer has the identical 0900 <rowCount> 1E000000 0700 header, so the shipped WCF event
read had the same latent multi-row truncation.
Fix: read a 10-byte buffer header (skip the 0x1E field once) and parse markerless rows;
accept container version 9 (WCF) and 11 (gRPC), mirroring the interface-version gate that
accepts History 11 and 12.
Verified: the real 50-row buffer now decodes to exactly 50 events, ending cleanly at
end-of-buffer (Parse_RealStockClientCapture_DecodesAllEvents, gated on
HISTORIAN_EVENT_CAPTURE_NDJSON so it skips without the gitignored capture), plus a
synthetic v11 golden test. 328 offline tests pass.
The parse path is now verified against the provided client's real event data on both
transports; the only remaining gap for gRPC events is the server delivering rows to our
connection (the documented retrieval-server-gate).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B6mcaT2PjRFKcogzp9UkfC
Pursued hypothesis #3 (connection-frame capture). Built a TLS-terminating tee proxy
(artifacts/.../httpcap/, gitignored: self-signed server cert, forwards through the
loopback tunnel, logs decrypted HTTP/1.1 + gRPC-Web both directions) and ran a native
capture-event (returns 50 rows) and our SDK diagnostic (0 rows) through the SAME
proxy/upstream for a clean A/B.
Findings:
- The stock client is gRPC-Web/HTTP-1.1 (alpn empty), and clientCert=none on every
connection — confirming (with the decompile) that hypothesis #2 (TLS client cert) is
moot: the native presents no client cert.
- Connection topology differs: the native opens 5 TLS connections, one per service, and
runs the event query (StartEventQuery/GetNext/EndEventQuery) on a DEDICATED
RetrievalService connection, separate from the HistoryService connection that opened and
registered the session. Our SDK collapses every service onto one connection. (Matches the
decompile: the stock client has a separate GrpcClientBase per service.)
- Framing differs benignly: native uses content-length + Expect: 100-continue; SDK uses
transfer-encoding: chunked. The server accepts both (StartEventQuery returns a valid
handle), so framing is not the gate. No hidden header on either side.
Tested the topology hypothesis with a new env-gated switch
(HISTORIAN_GRPC_EVENT_SPLIT_CHANNEL=1): run StartEventQuery/GetNext/EndEventQuery on a
dedicated RetrievalService connection (no re-handshake, reusing the session handle —
mirroring native conn4), registration staying on the main connection. Result: still
0B00000000001E000000 (0 rows), QH=1063. Splitting the event query onto its own connection
does not make rows flow — the server correlates by session handle, not connection, so
topology is not the row-scoping gate.
Every angle is now exhausted (payload, transport, metadata/interceptor/cert, topology,
data store). The gate is a server-internal per-connection retrieval working-set in the
native HistorianClient C++ core, unreachable from a pure-managed client. Conclusion
unchanged: auth-solved / retrieval-server-gated; ReadEventsAsync over gRPC keeps the
no-row throw, event reads use WCF. 56 offline gRPC/event tests pass.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B6mcaT2PjRFKcogzp9UkfC
Closed the blind spot the zero-rows conclusion had leaned on: prior cycles used wire
capture (instrument-grpc-nonstream hooks only byte[] params), blind to gRPC metadata,
interceptors, channel options. Read the stock managed source directly
(histsdk-2023r2-analysis/decompiled/Archestra.Historian.GrpcClient + HistorianAccess;
the pure-managed assemblies decompile cleanly though mixed-mode aahClientManaged crashes
ILSpy).
Findings:
- GrpcClientBase.InitializeBase uses GrpcWebHandler (GrpcWebMode, HttpVersion 1.1) — the
stock client speaks gRPC-Web over HTTP/1.1, the SAME transport as our SDK. This corrects
the premise of hypothesis #1: there was never a native Grpc.Core HTTP/2 path to differ
from; the stock client returning 50 rows is itself gRPC-Web. The HTTP/2 disproof's
conclusion stands and is reinforced (identical transport on both sides).
- m_metadata on every RPC (incl. StartEventQuery/GetNextEventQueryResultBuffer) is only
grpc-internal-encoding-request: gzip — exactly our header set. The ClientInterceptor is
a no-op (empty LogCall). So the "invisible per-connection metadata/header" blind spot is
confirmed empty — no hidden client-side identity the byte[] capture missed.
- CreateEventQuery/StartQuery/MoveNext are not in managed code; the managed
GrpcRetrievalClient.StartEventQuery is a thin one-RPC stub. The query logic lives in the
native C++/CLI HistorianClient core — consistent with the working-set being native/server-side.
Every client-controllable layer is now confirmed identical by reading the stock source,
not just by wire match: request bytes, transport, channel options, gRPC metadata,
interceptor. The remaining difference is below the managed surface / server-side.
Conclusion unchanged: gRPC event-row retrieval is auth-solved / retrieval-server-gated.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B6mcaT2PjRFKcogzp9UkfC
Pursued the two server-side/connection hypotheses from grpc-event-query-capture.md
for the gRPC event zero-rows blocker:
- #1 transport (DISPROVEN): native HTTP/2 (no GrpcWebHandler) returns the byte-identical
version-11 rowCount-0 terminal as gRPC-Web; the full v8 chain (ExchangeKey auth,
CM_EVENT registration, StartEventQuery) runs end-to-end over both. Added
HistorianGrpcChannelFactory.CreateHttp2 + HISTORIAN_GRPC_EVENT_HTTP2 switch.
- #4 SQL ground truth (ANSWERED): the event store has no per-connection column; the
rich Events view is served live by the Historian engine via the INSQL OLE DB
provider. Same engine + same window: 71,332 events via INSQL vs 0 via gRPC for our
connection. The data is global/unscoped — the gate is the gRPC RetrievalService's
per-connection in-process execution state, not data scoping or transport.
Three independent angles now exhausted (client payload byte-identical, transport
HTTP/2 == gRPC-Web, data store global). gRPC event-row retrieval stands documented as
auth-solved / retrieval-server-gated; ReadEventsAsync over gRPC keeps the no-row throw
and event reads use WCF. 326 offline tests pass.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B6mcaT2PjRFKcogzp9UkfC
Pursued the server-side SQL angle for the gRPC event zero-rows. Built a read-only
SOCKS5-relay + Microsoft.Data.SqlClient probe (gitignored, artifacts/.../sqlschema/)
and dumped the live Runtime event schema. Findings:
- No per-connection / per-client / per-session column exists anywhere in the event
store. The only scoping-like columns on Events/EventHistory/snapshots are event
content (Source_* origin, User_* acker, Provider_NodeName, SourceServer replication).
- The rich Events view is not a relational table — it is served live by the Historian
engine via the INSQL OLE DB provider (linked servers INSQL/INSQLD; encrypted remote
view). The SQL EventHistory base table holds only 168 rows / 1 tag.
- Decisive: for the SAME -90d..now window the gRPC StartEventQuery diagnostic returned
0 rows, the Events view via INSQL returns 71,332 events (most recent Alarm.Set firing
seconds before the probe). Same engine, same window — INSQL serves the data, gRPC
withholds it from our connection.
So there is nothing in the data to scope by: the zero-row gate is the gRPC
RetrievalService's per-connection in-process execution state, not data scoping or
transport (the same class of wall as DeleteTagExtendedProperties). Combined with the
transport disproof, three independent angles are now exhausted — client payload
(byte-identical), transport (HTTP/2 == gRPC-Web), and data store (global, unscoped).
gRPC event-row retrieval stands documented as auth-solved / retrieval-server-gated;
ReadEventsAsync over gRPC keeps the no-row throw and event reads use WCF.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B6mcaT2PjRFKcogzp9UkfC
Tested grpc-event-query-capture.md's leading next-session hypothesis — that the
native client's Grpc.Core HTTP/2 transport (vs our Grpc.Net.Client + GrpcWebHandler
gRPC-Web) is why event reads return zero rows. Added HistorianGrpcChannelFactory
.CreateHttp2 (plain HTTP/2 over SocketsHttpHandler, no gRPC-Web wrap) and an
HISTORIAN_GRPC_EVENT_HTTP2 switch on the event orchestrator (event path only; reads
stay gRPC-Web).
Live side-by-side against the event-bearing 2023 R2 server, everything else held
constant: the full v8 chain (ExchangeKey auth, CM_EVENT RegisterTags/EnsureTags=True,
StartEventQuery with a valid handle) runs end-to-end over BOTH native HTTP/2 and
gRPC-Web, and the server returns the byte-identical version-11 rowCount-0 terminal
(0B00000000001E000000) on both transports. Transport choice makes no difference —
the leading hypothesis is disproven and the zero-row scoping sits above the gRPC
transport layer.
Also confirmed the native capture-event harness queries a 30-day historical window
(returns 50 rows), so the native read is connection-scoped historical retrieval,
not a live subscription.
CreateHttp2 + the env switch + the EventChannelMode diagnostic are retained for
further connection-level probing. 44 offline tests pass; orchestrator stays on the
no-row throw.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B6mcaT2PjRFKcogzp9UkfC
Joseph Doherty