Tag rename has no dedicated WCF op — the (old,new) name batch rides the
generic History StartJob (StJb) job buffer; the server returns a job id and
applies renames asynchronously. Handle is the uppercase storage-session GUID,
Open2 in write mode; reuses the write orchestrator's open+priming chain.
jobBuffer layout (decoded + server-validated): byte[7] zero prefix + uint32
pairCount + per pair (uint32 oldCharCount + UTF-16 oldName + uint32
newCharCount + UTF-16 newName), order (old,new). The raw instrument capture
mangles the final byte with MDAS chunk markers (the R1.1 lesson), so the golden
fixture pins the CLEAN byte[] the SDK handed the channel (dumped via
AVEVA_HISTORIAN_RENAME_DUMP) — the exact buffer the live server accepted and
renamed with.
Gated server-side by the AllowRenameTags system parameter (default 0): when
disabled the native client rejects pre-wire (err 132); the managed SDK surfaces
it as StartJob=false -> Accepted=false. Enabling needs a Historian config
reload, not just a storage-engine restart.
Shipped: HistorianClient.RenameTagAsync/RenameTagsAsync -> HistorianTagRenameResult;
HistorianTagRenameProtocol; orchestrator RenameTags/SendStartJobRename; golden
WcfTagRenameProtocolTests (4, pins server-accepted buffer); gated live test
RenameTagsAsync_AgainstLocalHistorian_RenamesSandboxTag (passed end-to-end).
Native-harness `rename` scenario + Capture-RenameTags.ps1 + decode-rename-capture.py.
Doc: docs/reverse-engineering/wcf-rename-tags.md. 213 tests green.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B6mcaT2PjRFKcogzp9UkfC
Version-control the planning docs alongside the code they describe:
- grpc-transport.md — 2023 R2 gRPC transport analysis (sanitized source path)
- hcal-capability-matrix.md — HistorianAccess surface x gRPC ops x histsdk status x feasibility tiers
- hcal-roadmap.md — ordered build plan M0-M4 + cross-cutting workstreams
- histevents.md — how a HistorianEvent reaches the DB (client->wire->server)
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Joseph Doherty