From f1a030717c1200d72e9f7ff2f9d3d55aa460963a Mon Sep 17 00:00:00 2001
From: Mike Minutillo <mike.minutillo@particular.net>
Date: Fri, 27 Mar 2026 14:43:51 +0800
Subject: [PATCH] Do not return negative throughput when queue table deleted

---
 .../QueueTableSnapshot.cs                             |  2 +-
 .../SqlServerQuery.cs                                 | 11 +++++++----
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/src/ServiceControl.Transports.SqlServer/QueueTableSnapshot.cs b/src/ServiceControl.Transports.SqlServer/QueueTableSnapshot.cs
index 74c9bd18c9..c575c26d42 100644
--- a/src/ServiceControl.Transports.SqlServer/QueueTableSnapshot.cs
+++ b/src/ServiceControl.Transports.SqlServer/QueueTableSnapshot.cs
@@ -2,5 +2,5 @@ namespace ServiceControl.Transports.SqlServer;
 
 public class BrokerQueueTableSnapshot(BrokerQueueTable details) : BrokerQueueTable(details.DatabaseDetails, details.Schema, details.Name)
 {
-    public long RowVersion { get; set; }
+    public long? RowVersion { get; set; }
 }
\ No newline at end of file
diff --git a/src/ServiceControl.Transports.SqlServer/SqlServerQuery.cs b/src/ServiceControl.Transports.SqlServer/SqlServerQuery.cs
index e84e58b8c4..ca742d146d 100644
--- a/src/ServiceControl.Transports.SqlServer/SqlServerQuery.cs
+++ b/src/ServiceControl.Transports.SqlServer/SqlServerQuery.cs
@@ -70,11 +70,14 @@ public override async IAsyncEnumerable<QueueThroughput> GetThroughputPerDay(IBro
             var endData =
                 await queueTableName.DatabaseDetails.GetSnapshot(queueTableName, cancellationToken);
 
-            yield return new QueueThroughput
+            if (endData.RowVersion.HasValue && startData.RowVersion.HasValue)
             {
-                DateUTC = DateOnly.FromDateTime(timeProvider.GetUtcNow().DateTime),
-                TotalThroughput = endData.RowVersion - startData.RowVersion
-            };
+                yield return new QueueThroughput
+                {
+                    DateUTC = DateOnly.FromDateTime(timeProvider.GetUtcNow().DateTime),
+                    TotalThroughput = endData.RowVersion.Value - startData.RowVersion.Value
+                };
+            }
 
             startData = endData;
         }