From 96f10372dea471bfb0a950ccae0a1095adb788af Mon Sep 17 00:00:00 2001
From: Joseph Doherty <dohejw01@gmail.com>
Date: Thu, 25 Jun 2026 01:06:03 -0400
Subject: [PATCH] feat(grpc): add RunRawQueryOnSession seam for handshake-reuse
 spike

---
 .../Grpc/HistorianGrpcReadOrchestrator.cs     | 20 +++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/src/AVEVA.Historian.Client/Grpc/HistorianGrpcReadOrchestrator.cs b/src/AVEVA.Historian.Client/Grpc/HistorianGrpcReadOrchestrator.cs
index 74d0bad..d59d7bb 100644
--- a/src/AVEVA.Historian.Client/Grpc/HistorianGrpcReadOrchestrator.cs
+++ b/src/AVEVA.Historian.Client/Grpc/HistorianGrpcReadOrchestrator.cs
@@ -102,12 +102,28 @@ internal sealed class HistorianGrpcReadOrchestrator
         }
     }
 
+    // Spike/Phase-1 seam (pending.md A1): run a raw query against an EXTERNALLY-supplied, already-
+    // authenticated connection + client handle — i.e. NO Create()/handshake here. RunRawChain delegates
+    // to this so the per-call path and the reuse path share one query implementation (DRY). The handshake
+    // reuse-probe test drives this directly to measure whether the server honors a reused session.
+    internal List<HistorianSample> RunRawQueryOnSession(
+        HistorianGrpcConnection connection,
+        uint clientHandle,
+        string tag,
+        DateTime startUtc,
+        DateTime endUtc,
+        int maxValues,
+        CancellationToken cancellationToken)
+    {
+        HistorianDataQueryRequest request = HistorianWcfReadOrchestrator.BuildDataQueryRequest(tag, startUtc, endUtc, maxValues);
+        return RunQuery(connection, clientHandle, request, maxValues, cancellationToken);
+    }
+
     private List<HistorianSample> RunRawChain(string tag, DateTime startUtc, DateTime endUtc, int maxValues, CancellationToken cancellationToken)
     {
         using HistorianGrpcConnection connection = HistorianGrpcChannelFactory.Create(_options);
         uint clientHandle = OpenAuthenticatedConnection(connection, cancellationToken);
-        HistorianDataQueryRequest request = HistorianWcfReadOrchestrator.BuildDataQueryRequest(tag, startUtc, endUtc, maxValues);
-        return RunQuery(connection, clientHandle, request, maxValues, cancellationToken);
+        return RunRawQueryOnSession(connection, clientHandle, tag, startUtc, endUtc, maxValues, cancellationToken);
     }
 
     private List<HistorianAggregateSample> RunAggregateChain(